View allAll Photos Tagged Absorption
The absorption of the ancient kingdom of Strathclyde into the new kingdom of Scotland was a gradual process, with the Scots heir apparent often acting as ruler of Strathclyde. When Malcolm II died in 1034, his grandson, Duncan of Strathclyde ascended the throne as King Duncan I (only to be killed in battle by MacBeth in 1040). In 1113, Prince David, later King David I, governed southern Scotland, including Strathclyde, while his elder brother, Alexander I, ruled as King of Scots. Quite what purpose Dumbarton served during this time, is not known, but eventually, owing to a new threat in the west, it must have become necessary to fortify it again.
The new threat came about because in 1098, King Edgar was forced to concede Argyll and the Hebrides to the King of Norway, which meant that Dumbarton was only ten miles from the Norwegian border! While this would suggest Dumbarton was re-fortified, there is no mention of a stronghold until 1222, when King Alexander II's foundation charter for the burgh of Dumbarton mentions the 'new castle' here.
By this date, relations between Scotland and Norway were extremely strained. Alexander had recently led an expedition into Argyll to try to reclaim it. Haakon IV of Norway retaliated in 1230 by sending a fleet into the Clyde. Haakon himself led another armada in 1263, which ended in tactical stalemate (but strategic Scottish victory) at the Battle of Largs. Three years later, Haakon's successor King Magnus, and Alexander III of Scotland, signed the Treaty of Perth, that returned the Hebrides to Scotland. Dumbarton was a frontier post no more.
The Hague
March 2012
The Netherlands
Urban life in the Netherlands
Ricoh GRD IV
Please do not reproduce or use this picture without my explicit permission.
If you ask nicely i will probably say yes, just ask me first!
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Size: 70 * 138 cm.
Colour: White with Gold Flecks
Weight: 313 g for pack of 10
Type: Half-Sized Xuan Paper
Materials: 灯心草 Juncus effusus rushes and 硬质早熟禾 Poa sphondylodes Trin.
Suitable for all types of paintings and calligraphy.
Finish: the paper is half-sized and the absorption rate is lower than raw Xuan Paper but higher than sized Xuan Paper.
Handmade with traditional recipe.
Price is for one pack of 10 sheets 70 * 138 cm half-sized xuan papers.
Shrimp is a good source of vitamin D. Vitamin D regulates the absorption of calcium and phosphorus, which is essential for having a strong teeth and bones.
Had a pair of broadband diffuser/absorption acoustic panels built. Combined with a set of heavy, lined velvet curtains to cover the big glass doors out to the deck, the improvement in room sonics is incredible.
Also known as lingonberries.
I was able to return home in time to pick cranberries. Best time to pick them is after the first frost.
Here is some additional information about these berries:
Lingonberries are an excellent source of antioxidants. Antioxidants are a group of biochemicals shown to be an important part of the human diet partially due to their ability to effect the aging pro- cess.
Researchers use the oxygen radical absorption capacity test (ORAC) to measure levels of antioxi- dants in foods. Lingonberries scored a 203. Any score above 40 is considered very high.
A self- portrait done for fun, using the computer cam (so not high resolution, but useful as a thumbnail for my Flickr icon) - Done whilst studying the Nikon manual. The idea was to try to catch that quizzical, enigmatic expression we all seem to wear when studying a manual.
The Hague
June 2012
The Netherlands
Candid shots in and around the Public Transport in The Netherlands
Ricoh GRD IV
Please do not reproduce or use this picture without my explicit permission.
If you ask nicely I will probably say yes, just ask me first!
If you happen to be in one of my frames and have any objections to this.
Please contact me!
Please no glossy awards, scripted comments and big thumbnails back to your own work.
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All rights reserved
The dominant sky colouring processes are:
1. Rayleigh scattering
2. Aerosol (Mie) scattering
3. Water vapour absorption
4. Ozone absorption
The first two make the clouds (reflected sunlight) red rather than purple.
The third removes some of the deep red light.
The fourth removes most of the orange and yellow and some of the green light form the entire scene (blue sky and clouds). Without the ozone, the colour palette would be very markedly different with a strong orange cast and less saturated colours.
Note: replaced on 19 Dec with a version processed using a 'daylight' rather than an 'auto' white balance
Credit: Trish Fosbury for noticing the sunset happening!
Its been a while but yesterday the sun was shining so out came the Infra Red cameras and Claire and i went for a stroll around Saltwell Park in Gateshead. The trees are all pretty much bare so i wasnt really feeling inspired and didnt take any shots but pulled off a sneaky detour to the Angel on the way home.... The Angel looked great soaking up the rays so i walked down one on the small gully's and took this 2 shot vertorama with my Sony F717 as the lens isnt wide enough to cram in the whole thing. I had my Hoya R72 & Hoya ND8 stacked on the camera which was in the Nightshot mode. This flips the IR Cut Filter (Hot Mirror) out of the way meaning with the right filter you get IR shots without any modding...
The weather seems to have turned and it was a pleasant sight seeing sunlight and a cracking orb like red sun drop just before... Come on Spring, i want to use these cameras more!! :D
Scheveningen/The Hague
May 2012
The Netherlands
Beachlife in the Netherlands
Ricoh GRD IV
Please do not reproduce or use this picture without my explicit permission.
If you ask nicely I will probably say yes, just ask me first!
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Please no glossy awards, scripted comments and big thumbnails back to your own work.
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Following the absorption of Fylde Borough's Blue Bus Fleet, this Atlantean has been painted into Blackpool Transport livery.
BTS depot yard, 6th July 1999
Leiden
March 2012
The Netherlands
Urban life in the Netherlands
Ricoh GRD IV
Please do not reproduce or use this picture without my explicit permission.
If you ask nicely i will probably say yes, just ask me first!
If you happen to be in one of my frames and have any objections to this.
Please contact me!
All rights reserved
The Hague
The Netherlands
2013
Candid shots in and around the Public Transport in The Netherlands
Ricoh GRD IV
This plot shows the changes in brightness and colour of the Sun as it approaches the horizon at sunset. The labels on the sequence of observations in the plot show the colour temperature of the sunlight through the sequence (eg 4150K for the first one). This can be compared with the CT value of the LED lamps you buy to illuminate your home.
The individual spectra can be mathematically modelled to give some information about the state and and content of the atmosphere.
Some more technical details are given in what follows.
+++++++++++++++++++++++
These measurements were made in Bath, UK on the evening of 22 March 2020. The conditions were clear with little haze but with some very light patches of high cloud.
The instrument used was a Sekonic C-7000 SpectroMaster fitted with a tubular shade over the cosine corrector that restricted the field-of-view to a diameter of 10.8° (full illumination) ramping down to zero at 21.2°.
The spectral irradiance was measured at the following apparent (refraction-corrected) solar altitudes calculated from the "NOAA_Solar Calculations_day" spreadsheet ( www.esrl.noaa.gov/gmd/grad/solcalc/calcdetails.html ) using the UTC time and the Latitude and Longitude of the location in Bath.
Observation sequence number__Apparent Solar Altitude (deg)
086_______________________10.3
087_______________________5.2
088 ______________________3.9
089_______________________2.6
090_______________________2.2
091_______________________1.8
They covered a range of Air Masses (AM) of 5.4 to 20.6 (calculated from the formula given in: Kasten, F., and A. T. Young. 1989. "Revised optical air mass tables and approximation formula" Applied Optics 28:4735–4738.
The graphic shows the measurements (thick coloured lines) on a logarithmic scale of spectral irradiance. The thin grey line show the Solar spectrum outside the atmosphere (peaking at 2 W/m^2/nm) and two extinction models with air masses corresponding to the apparent solar altitudes of observations 086 (pale green) and 089 (violet).
The extinction model incorporates Rayleigh scattering, aerosol scattering (with a default power-law slope (spectral index) of -1.3) and ozone absorption in the Hartley, Huggins and Chappuis bands. The fits are made using modest adjustments to the default values of the aerosol spectral index, the aerosol column density wrt to a 'standard atmosphere' (Allen, Astrophysical Quantities, 3rd edition, 1973) and the Ozone STP atmospheric depth of 3mm.
Note that other significant telluric (Earth atmosphere) absorptions are not included in this model, notably water vapour, molecular oxygen, the O2*O2 dimer (or Collisionally Induced Absorption, CIA) and nitrogen dioxide absorption in the blue part of the spectrum. The water and oxygen account for the three strong absorption bands longward of 670nm.
An interesting feature of the sequence is the increasing strength of the absorption band at ~570nm in the yellow part of the spectrum. This is due to the oxygen dimer (CIA) absorption which is dependent on both the oxygen column density AND the pressure — since two oxygens need to interact. Most of these absorptions therefore occur in the low atmosphere where the pressure is highest. There is also a weaker CIA band close to 630nm associated with, but broader than, the molecular oxygen absorption at that wavelength. (See the comment below).
The extinction model spectrum (thin violet line) starts to fall well below the observed spectrum (#089) below 450nm. This indicates the presence of significant multiple scattering in long paths through the low atmosphere, especially from aerosols. My simple model assumes single scattering.
For this gentle and relaxing photowalk in my district, Lyon, France, I brought along my French TLR SEMFLEX Standard 3.5 camera (see below for details) loaded with a never-tried yet film Svema FOTO 100 made in Ukraine. The backing paper is black with white numbering and signaling symbols are easy to read across the small red window of my SEMFLEX.
For all the frames, my SEMFLEX was equipped with the original SEMFLEX squared shade hood a SEMFLEX yellow filter x2. The film was exposed for 50 ISO to compensate the light absorption of the yellow filter. Metering was done using a Minolta Autometer III equipped with a 10° finder for selective measures privileging the shadow areas or an opale dome for incident light integration.
View n° 10: 1/100s f/8 focusing @ 50 m, SEMFLEX Yellow filter x2
Rue Bleton (Ecole Providence des Trinitaires), May 10, 2025
69004 Lyon
France
After the view #12 exposed, the film was fully rolled to the taking spool and was developed in a Paterson tank with a spiral adapted to the 120-format film. 500 mL of Adox Adonal (Agfa Rodinal) developer were prepared at the dilution 1+25 and the film processed for 7 min at 20°C. The first view was shifted by about two frames leading to only 10 views on the film. This is clearly due to a quality problem. The backing paper was improperly positioned during the spooling of the film.
Digitizing of the remaining 10 frames, was made using a Sony A7 camera (ILCE-7, 24MP) held on a Minolta vertical macro stative device and adapted to a Minolta MD Macro lens 1:3.5 f=50mm. The light source was a LED panel (approx. 4x5') CineStill Cine-lite fitted with film holder "Lobster" to maintain flat the 70mm films.
The RAW files obtained were inverted within LR and edited to the final jpeg pictures without intermediate file. They are presented either as printed files with frame or the full size JPEG together with some documentary smartphone pictures..
About the camera and lenses :
My French Semflex TLR year 1959-1960 is equipped with triplet 1/3.5 f=75mm SOM Berthiot lenses as descripted bellow.
The SEM company ("Société des Etablissements Modernes de Mécanique") was founded in France by Paul Royet in 1946, in the small city of Aurec near Saint-Etienne (Loire). The SEM camera's was known essentially for the TLR Semflex that were a great commercial success in France until the 70's. The camera's are constructed around an injected aluminum alloy chassis, very resistant and rigid permitting precise optical alignments. The focusing mechanism is made of a cam system like the Rolleiflex giving an accurate and smooth focusing. SEM constructed their own shutters called Orec with 5 leaves capable of the 1/400s to 1s with B.
Semflex received in majority French optics Berthiot with 3 or 4 lenses (Tessar type). Some camera's were also mounted with Angénieux lenses.
Semflex were trusted TLR camera's used by amateurs and for professional purposes. From 1949 to 1976, 171.000 Semflex were produced in many different types and versions.
My Semflex in a middle grade version Standard 3.5 type-10 (1959-1960). It was the last version mounted with the 3-lens SOM Berthiot 1:3.5 f=75mm. I got the camera with set of accessories and several documents including the user manual of the Semflex Standard 4.5 versions. The accessories include a leather SEM ever-ready bag, a Semflex push-on shade hood, a Semflex push-on yellow filter x2 in its original box, and close-focusing lenses. The 1D one is constructed with a prism for the finder lens that compensates the parallax in the zone 1m to 0.5m.
The decorative ring around each lenses can also receive push-on accessories in 36mm diameter as the FOCA or Leitz 36mm filter series. I adapted two protective lens caps from Kodak film canister snapped covers.
New to Truronian 4/2001 and remained so until absorption into the First Group.
Here she is heading down Station Road, having come off working the 924 college service St Austell - Truro.
The Hague
March 2012
The Netherlands
The obligatory derelict bike shot..
(can't escape them here in The Netherlands)
Urban life in the Netherlands
Ricoh GRD IV
Please do not reproduce or use this picture without my explicit permission.
If you ask nicely i will probably say yes, just ask me first!
If you happen to be in one of my frames and have any objections to this.
Please contact me!
All rights reserved
Once wore the green of Dundee Corporation but seen here shortly after absorption by Tayside Regional Council.
Ultimecia uses her ability to compress time to try and become omnipotent through the absorption of all time, space, and existence. She can invade and control an individual's body and mind both internally and externally. Ultimecia can reach into a person's mind to steal or give life to thoughts, knowledge, and magic.
A short series of 6 photographs taken at the Centre Pompidou.
Une petite série de 6 photos prises au Centre Pompidou.
If you recognise yourself in these photos and prefer they are not here, just let me know (or if you would like a copy of the photo).
Si vous vous reconnaissez dans cette photo et préfériez que la photo ne soit pas publiée, dites le moi (ou bien si vous aimeriez en avoir une copie).
Amsterdam
The Netherlands
2012
Candid shots in and around the Public Transport in The Netherlands
Ricoh GRD IV
Once a bracket for a bird feeder. Now it feeds a hungry Live Oak tree. No rescue, no freedom, no release. And no chance of parole...
The black-crowned sparrow-lark (Eremopterix nigriceps) is well-suited to desert environments due to a variety of physiological, behavioral, and morphological adaptations. Here are some key reasons why this bird thrives in arid conditions:
1. Camouflage and Heat Reflection
Plumage Adaptation: The bird's light-colored underparts reflect sunlight, reducing heat absorption, while its darker upper parts help it blend into the desert terrain, providing camouflage from predators.
2. Water Conservation
Efficient Water Use: Black-crowned sparrow-larks can survive on minimal water, obtaining most of their hydration from the food they consume, such as seeds and insects.
Concentrated Waste: Their kidneys are adapted to excrete highly concentrated uric acid, minimizing water loss.
3. Diet
Flexible Feeding Habits: The diet consists of seeds and insects, which are abundant in deserts during certain seasons. Insects provide both energy and moisture.
4. Thermoregulatory Behavior
Activity Timing: These larks are most active during the cooler parts of the day, such as early morning and late evening, to avoid the extreme heat of midday.
Shade Seeking: They rest in shaded areas during the hottest parts of the day to reduce heat stress.
5. Efficient Locomotion
Ground Adaptation: They are adept at walking and running, minimizing energy expenditure compared to flying long distances in the heat.
6. Breeding Adaptations
Nesting in Shade: Their nests are often placed in shaded spots or depressions in the ground, providing some protection from the sun.
Egg Adaptation: The eggs are resistant to dehydration and can withstand high temperatures.
7. Social and Communication Skills
Group Living: These birds often live in small flocks, which can help them locate resources more efficiently in the sparse desert environment.
Vocal Communication: They use calls to communicate over long distances, reducing the need to expend energy searching for others.
The Hague
May 2012
The Netherlands
A rather idyllic church garden, not very well known to the general public, although it has been busier in the last few years. Used to be a preferred spot for junkies and dealers for hustling and using. Now its a place for lunch, conversation and the occasional joint.
Urban life in the Netherlands
Ricoh GRD IV
Please do not reproduce or use this picture without my explicit permission.
If you ask nicely I will probably say yes, just ask me first!
If you happen to be in one of my frames and have any objections to this.
Please contact me!
Please no glossy awards, scripted comments and big thumbnails back to your own work.
I will remove them...
Improved insole; premium, 3x better moisture absorption, 100% better energy absorption
•Standard: EN ISO 20345:2011 S5 CI SRC
•Resistance: minerals, animal and plant oils and fats, disinfectants, fertilizer, solvents, various chemicals
•Lining; antibacterially treated, recognisable Dunlop red
A Sri Lankan girl drawing at an arts exhibition.
"Every child is an artist. The problem is how to remain an artist once we grow up." - Pablo Picasso.
This is an unusually rich view of the Earth's telluric absorption spectrum obtained using the addition of many spectra of the underside of a dark thundercloud obtained in Munich in August 2014. More details of these observations can be seen at:
www.flickr.com/photos/bob_81667/49778550932/in/album-7215...
The Solar altitude at the time was 45° and so the normal telluric spectrum of the sky would be weak and rather unimpressive. In this case however, the light reaching the spectrometer had experienced a long path through the towering cloud and had scattered many times from water drops, other aerosols and air molecules with much of the path happening at low altitudes where the pressure is highest.
Such a random walk through the cloud can accumulate a long pathlength's worth of travel through a medium that will contain a high proportion of absorbers and scatterers such as water that predominate at low altitudes.
One species that will be under-represented is ozone (O_3) because this gas is only present in any quantity above about 12km — although some will be produced locally by lightning flashes.
Another oxygen 'molecule' however will be over-represented since its density depends on the square of the gas pressure. This is tetra-oxygen (O_4) which is a transitory (very short-lived) association of two oxygen molecules that allows the formation of spectral bands from normally electric dipole forbidden transitions. These O_4 bands are called Collisional Induced Absorptions (CIA). The short lifetime of these collision interactions results — basically because of Heisenberg's Uncertainty Principle — in spectral lines being substantially broadened. This process was only discovered in the mid-20th century and the full quantum-mechanical explanation has only recently been explored by Tijs Karman and co-workers in the Netherlands (Karman, T., Koenis, M.A.J., Banerjee, A. et al. Publisher Correction: O2−O2 and O2−N2 collision-induced absorption mechanisms unravelled. Nature Chem 10, 573 (2018). doi.org/10.1038/s41557-018-0063-2).
These distinctive absorption bands were seen by the 19th century observers such as Ångström and others at sunset and sunrise but, although they realised that the bands behaved differently from those due to water vapour and the normal O_2 molecule, they were not able to identify them.
The green and violet lines in the plot show processed versions of the observed cloud spectra which have been normalised by a process described in the previous posts referred to above. This results in a flat continuum which is free from all of the absorptions in the Sun's atmosphere: the Fraunhofer lines have gone.
The thin violet spectrum contains all of the telluric features including the complex spectrum of nitrogen dioxide (NO_2) which occupies the blue and green part of the spectrum only. The thick green line has the NO_2 spectrum removed assuming a column density of 2.5e17/cm2. This rather high density is probably predominantly the result of the formation of NO_2 in lightning flashes and not necessarily by vehicle exhaust pollution. Cross-section data for NO_2 can be obtained from:
www.frontiersin.org/articles/10.3389/fenvs.2019.00118/full
A model of the computed O_4 spectrum corresponding to a column of 2e44 cm^5 molecule^-2 using the HITRAN database ( www.sciencedirect.com/science/article/pii/S0022407311003773 ) is shown as the dashed red line.
In this case the telluric spectrum is dominated by the the bands of water vapour whose strength increases towards the infrared. These are overtones (harmonics) of the fundamental vibrations of the water molecule that include symmetric and asymmetric stretch of the two hydrogen atoms with respect to the central oxygen, the oscillation of angular separation of the hydrogens around a mean angle of about 105° and librations around three axes (see: www1.lsbu.ac.uk/water/water_vibrational_spectrum.html ). These higher harmonics cause depths of a metre or so of clear water to appear blue. See my discussion of water spectra at: www.flickr.com/photos/bob_81667/6309336354
The spectra also include emission from some lightning flashes (the spectra were selected to avoid strong lightning flashes) which have not been marked but can be identified by looking at:
www.flickr.com/photos/bob_81667/4951867947/
Note that there is no visible sign of ozone which only dominates the spectrum near twilight.
I have included on the plot overlays of two of the maps of the atmospheric spectrum made by Ångström. The top one, made by Ångström and Thalén is taken from the book "Spectrum Analysis" by H. Schellen published in 1872 and reproduced by the Scholarly Publication Office of the University of Michigan University Library (which I gratefully acknowledge as the source) as part of Plate VI.
The second map (left-right mirrored) is from the same volume as Fig. 95. While these two maps are very similar, there is a significant change in the position of the blue absorption band marked as Greek(lambda) in the lower map. What is apparently the same band appears shifted some 14nm to the blue. This band, which appears strongly in my cloud spectrum at a wavelength consistent with the lower map, is hard to see in a visual spectroscope (I have yet to observe it!) and one can perhaps excuse Ångström — who is renowned for his exquisite precision — for getting it wrong the first (?) time. Remember that he did not have access to the digital manipulation of spectra that I have now! He had to disentangle the telluric spectrum from that of the sun by eye, a task that is considerably easier in the red than in the blue.
Since all of these telluric features result from transitions in molecules, they tend to be more frequent and stronger towards longer wavelengths, leaving the visible and ultraviolet spectrum dominated by atomic processes. It is perhaps remarkable that some of the most obvious features to our eyes are due to the somewhat esoteric and only lately understood process of CIA. Indeed, the yellow/orange part of the spectrum seen through a spectroscope is dominated by an almost transparent region between about 580 and 590nm that is bounded on the blue side by the strongest O4 band at 576nm and, on the red side, by "The Rainband" of water from 590 to just over 600nm. This leaves what almost appears as a yellow/orange emission band in the region of the spectrum to which our eyes are most sensitive.
Another interesting telluric spectral feature can be see at the violet end of this spectrum, again enhanced in the cloud spectrum due to the long high pressure pathlength of the light. The majority of scatterings of photons by molecules or aerosols in the atmosphere are 'elastic', ie. do not involve a change of wavelength between the incident and the scattered photon. A small fraction are however 'inelastic', meaning that some energy is transferred from the photon to produce internal vibrations in the molecule. [Note that this process can happen in reverse but that is very rare and most of the outgoing photons are redder that the original one.]
In the case of the solar spectrum scattered in the Earth's atmosphere, especially in clouds, a small fraction of the photons at each wavelength will be Raman scattered towards longer wavelengths. If the Solar spectrum was perfectly flat, this would make little difference. When there are strong, deep absorption lines however, more light will be scattered into an absorption line than out of it. This will result the spectrum of skylight having slightly shallower lines than the Fraunhofer absorption lines in in the Sun. See the discussion of the phenomenon in:
www.researchgate.net/publication/253321609_The_Ring_Eect_...
This process, called Raman scattering after the Indian Nobel Laureate in physics (1930) who discovered it with his student K. S. Krishnan, is now very widely used in science, technology and forensics to study and identify materials of many sorts. When we remove the Solar lines by dividing our cloud spectrum by the Sun, we can see the strong lines appearing in apparent 'emission'. The Ca II H & K lines, being the strongest is the spectrum, offer the best chance of seeing the effect appearing in our plot.
This nice example of a telluric spectrum gives an idea of the kind of spectrum that we might hope or expect to see from an exoplanet in the 'habitable zone' orbiting another sun-like star when our instruments allow us the capability to see this level of detail (which may take a while!)
Squid are cephalopods in the superorder Decapodiformes with elongated bodies, large eyes, eight arms and two tentacles. Like all other cephalopods, squid have a distinct head, bilateral symmetry, and a mantle. They are mainly soft-bodied, like octopuses, but have a small internal skeleton in the form of a rod-like gladius or pen, made of chitin.
Squid diverged from other cephalopods during the Jurassic and occupy a similar role to teleost fish as open water predators of similar size and behaviour. They play an important role in the open water food web. The two long tentacles are used to grab prey and the eight arms to hold and control it. The beak then cuts the food into suitable size chunks for swallowing. Squid are rapid swimmers, moving by jet propulsion, and largely locate their prey by sight. They are among the most intelligent of invertebrates, with groups of Humboldt squid having been observed hunting cooperatively. They are preyed on by sharks, other fish, sea birds, seals and cetaceans, particularly sperm whales.
Squid can change colour for camouflage and signalling. Some species are bioluminescent, using their light for counter-illumination camouflage, while many species can eject a cloud of ink to distract predators.
Squid are used for human consumption with commercial fisheries in Japan, the Mediterranean, the southwestern Atlantic, the eastern Pacific and elsewhere. They are used in cuisines around the world, often known as "calamari". Squid have featured in literature since classical times, especially in tales of giant squid and sea monsters.
TAXONOMY AND PHYLOGENY
Squid are members of the class Cephalopoda, subclass Coleoidea. The squid orders Myopsida and Oegopsida are in the superorder Decapodiformes (from the Greek for "ten-legged"). Two other orders of decapodiform cephalopods are also called squid, although they are taxonomically distinct from squids and differ recognizably in their gross anatomical features. They are the bobtail squid of order Sepiolida and the ram's horn squid of the monotypic order Spirulida. The vampire squid, however, is more closely related to the octopuses than to any squid.
The cladogram, not fully resolved, is based on Sanchez et al, 2018. Their molecular phylogeny used mitochondrial and nuclear DNA marker sequences; they comment that a robust phylogeny "has proven very challenging to obtain". If it is accepted that Sepiidae cuttlefish are a kind of squid, then the squids, excluding the vampire squid, form a clade as illustrated. Orders are shown in boldface; all the families not included in those orders, except Sepiadariidae and Sepiidae are in the paraphyletic order "Sepiida", are in the paraphyletic order "Oegopsida".
EVOLUTION
Crown coleoids (the ancestors of octopuses and squid) diverged at the end of the Paleozoic, in the Permian. Squid diverged during the Jurassic, but many squid families appeared in or after the Cretaceous. Both the coleoids and the teleost fish were involved in much adaptive radiation at this time, and the two modern groups resemble each other in size, ecology, habitat, morphology and behaviour, however some fish moved into fresh water while the coleoids remained in marine environments.
The ancestral coleoid was probably nautiloid-like with a strait septate shell that became immersed in the mantle and was used for buoyancy control. Four lines diverged from this, Spirulida (with one living member), the cuttlefishes, the squids and the octopuses. Squid have differentiated from the ancestral mollusc such that the body plan has been condensed antero-posteriorly and extended dorso-ventrally. What may have been the foot of the ancestor is modified into a complex set of appendages around the mouth. The sense organs are highly developed and include advanced eyes similar to those of vertebrates.
The ancestral shell has been lost, with only an internal gladius, or pen, remaining. The pen, made of a chitin-like material, is a feather-shaped internal structure that supports the squid's mantle and serves as a site for muscle attachment. The cuttlebone or sepion of the Sepiidae is calcareous and appears to have evolved afresh in the Tertiary
DESCIPTION
Squid are soft-bodied molluscs whose forms evolved to adopt an active predatory lifestyle. The head and foot of the squid are at one end of a long body, and this end is functionally anterior, leading the animal as it moves through the water. A set of eight arms and two distinctive tentacles surround the mouth; each appendage takes the form of a muscular hydrostat and is flexible and prehensile, usually bearing disc-like suckers.
The suckers may lie directly on the arm or be stalked. Their rims are stiffened with chitin and may contain minute toothlike denticles. These features, as well as strong musculature, and a small ganglion beneath each sucker to allow individual control, provide a very powerful adhesion to grip prey. Hooks are present on the arms and tentacles in some species, but their function is unclear. The two tentacles are much longer than the arms and are retractile. Suckers are limited to the spatulate tip of the tentacle, known as the manus.
In the mature male, the outer half of one of the left arms is hectocotylised – and ends in a copulatory pad rather than suckers. This is used for depositing a spermatophore inside the mantle cavity of a female. A ventral part of the foot has been converted into a funnel through which water exits the mantle cavity.
The main body mass is enclosed in the mantle, which has a swimming fin along each side. These fins are not the main source of locomotion in most species. The mantle wall is heavily muscled and internal. The visceral mass, which is covered by a thin, membranous epidermis, forms a cone-shaped posterior region known as the "visceral hump". The mollusc shell is reduced to an internal, longitudinal chitinous "pen" in the functionally dorsal part of the animal; the pen acts to stiffen the squid and provides attachments for muscles.
On the functionally ventral part of the body is an opening to the mantle cavity, which contains the gills (ctenidia) and openings from the excretory, digestive and reproductive systems. An inhalant siphon behind the funnel draws water into the mantel cavity via a valve. The squid uses the funnel for locomotion via precise jet propulsion. In this form of locomotion, water is sucked into the mantle cavity and expelled out of the funnel in a fast, strong jet. The direction of travel is varied by the orientation of the funnel. Squid are strong swimmers and certain species can "fly" for short distances out of the water.
CAMOUFLAGE
Squid make use of different kinds of camouflage, namely active camouflage for background matching (in shallow water) and counter-illumination. This helps to protect them from their predators and allows them to approach their prey.
The skin is covered in controllable chromatophores of different colours, enabling the squid to match its coloration to its surroundings. The play of colours may in addition distract prey from the squid's approaching tentacles. The skin also contains light reflectors called iridophores and leucophores that, when activated, in milliseconds create changeable skin patterns of polarized light. Such skin camouflage may serve various functions, such as communication with nearby squid, prey detection, navigation, and orientation during hunting or seeking shelter. Neural control of the iridophores enabling rapid changes in skin iridescence appears to be regulated by a cholinergic process affecting reflectin proteins.
Some mesopelagic squid such as the firefly squid (Watasenia scintillans) and the midwater squid (Abralia veranyi) use counter-illumination camouflage, generating light to match the downwelling light from the ocean surface. This creates the effect of countershading, making the underside lighter than the upperside.
Counter-illumination is also used by the Hawaiian bobtail squid (Euprymna scolopes), which has symbiotic bacteria (Aliivibrio fischeri) that produce light to help the squid avoid nocturnal predators. This light shines through the squid's skin on its underside and is generated by a large and complex two-lobed light organ inside the squid's mantle cavity. From there, it escapes downwards, some of it travelling directly, some coming off a reflector at the top of the organ (dorsal side). Below there is a kind of iris, which has branches (diverticula) of its ink sac, with a lens below that; both the reflector and lens are derived from mesoderm. The squid controls light production by changing the shape of its iris or adjusting the strength of yellow filters on its underside, which presumably change the balance of wavelengths emitted. Light production shows a correlation with intensity of down-welling light, but it is about one third as bright; the squid can track repeated changes in brightness. Because the Hawaiian bobtail squid hides in sand during the day to avoid predators, it does not use counter-illumination during daylight
PREDATOR DISTRACTION WITH INK
Squid distract attacking predators by ejecting a cloud of ink, giving themselves an opportunity to escape. The ink gland and its associated ink sac empties into the rectum close to the anus, allowing the squid to rapidly discharge black ink into the mantle cavity and surrounding water. The ink is a suspension of melanin particles and quickly disperses to form a dark cloud that obscures the escape manoeuvres of the squid. Predatory fish may also be deterred by the alkaloid nature of the discharge which may interfere with their chemoreceptors.
NERVOUS SYSTEM AND SENSE ORGANS
Cephalopods have the most highly developed nervous systems among invertebrates. Squids have a complex brain in the form of a nerve ring encircling the oesophagus, enclosed in a cartilaginous cranium. Paired cerebral ganglia above the oesophagus receive sensory information from the eyes and statocysts, and further ganglia below control the muscles of the mouth, foot, mantle and viscera. Giant axons up to 1 mm in diameter convey nerve messages with great rapidity to the circular muscles of the mantle wall, allowing a synchronous, powerful contraction and maximum speed in the jet propulsion system.
The paired eyes, on either side of the head, are housed in capsules fused to the cranium. Their structure is very similar to that of a fish eye, with a globular lens that has a depth of focus from 3 cm to infinity. The image is focused by changing the position of the lens, as in a camera or telescope, rather than changing the shape of the lens, as in the human eye. Squid adjust to changes in light intensity by expanding and contracting the slit-shaped pupil. Deep sea squids in the family Histioteuthidae have eyes of two different types and orientation. The large left eye is tubular in shape and looks upwards, presumably searching for the silhouettes of animals higher in the water column. The normally-shaped right eye points forwards and downwards to detect prey.
The statocysts are involved in maintaining balance and are analogous to the inner ear of fish. They are housed in cartilaginous capsules on either side of the cranium. They provide the squid with information on its body position in relation to gravity, its orientation, acceleration and rotation, and are able to perceive incoming vibrations. Without the statocysts, the squid cannot maintain equilibrium. Squid appear to have limited hearing, but the head and arms bear lines of hair-cells that are weakly sensitive to water movements and changes in pressure, and are analogous in function to the lateral line system of fish.
REPRODUCTIVE SYSTEM
The sexes are separate in squid, there being a single gonad in the posterior part of the body with fertilisation being external, and usually taking place in the mantle cavity of the female. The male has a testis from which sperm pass into a single gonoduct where they are rolled together into a long bundle, or spermatophore. The gonoduct is elongated into a "penis" that extends into the mantle cavity and through which spermatophores are ejected. In shallow water species, the penis is short, and the spermatophore is removed from the mantle cavity by a tentacle of the male, which is specially adapted for the purpose and known as a hectocotylus, and placed inside the mantle cavity of the female during mating.The female has a large translucent ovary, situated towards the posterior of the visceral mass. From here, eggs travel along the gonocoel, where there are a pair of white nidamental glands, which lie anterior to the gills. Also present are red-spotted accessory nidamental glands containing symbiotic bacteria; both organs are associated with nutrient manufacture and forming shells for the eggs. The gonocoel enters the mantle cavity at the gonopore, and in some species, receptacles for storing spermatophores are located nearby, in the mantle wall. In shallow-water species of the continental shelf and epipelagic or mesopelagic zones, it is frequently one or both of arm pair IV of males that are modified into hectocotyli. However, most deep-sea squid lack hectocotyl arms and have longer penises; Ancistrocheiridae and Cranchiinae are exceptions. Giant squid of the genus Architeuthis are unusual in that they possess both a large penis and modified arm tips, although whether the latter are used for spermatophore transfer is uncertain. Penis elongation has been observed in the deep-water species Onykia ingens; when erect, the penis may be as long as the mantle, head, and arms combined. As such, deep-water squid have the greatest known penis length relative to body size of all mobile animals, second in the entire animal kingdom only to certain sessile barnacles.
DIGESTIVE SYSTEM
Like all cephalopods, squids are predators and have complex digestive systems. The mouth is equipped with a sharp, horny beak mainly made of chitin and cross-linked proteins, which is used to kill and tear prey into manageable pieces. The beak is very robust, but does not contain minerals, unlike the teeth and jaws of many other organisms; the cross-linked proteins are histidine- and glycine-rich and give the beak a stiffness and hardness greater than most equivalent synthetic organic materials. The stomachs of captured whales often have indigestible squid beaks inside. The mouth contains the radula, the rough tongue common to all molluscs except bivalvia, which is equipped with multiple rows of teeth.[6] In some species, toxic saliva helps to control large prey; when subdued, the food can be torn in pieces by the beak, moved to the oesophagus by the radula, and swallowed.
The food bolus is moved along the gut by waves of muscular contractions (peristalsis). The long oesophagus leads to a muscular stomach roughly in the middle of the visceral mass. The digestive gland, which is equivalent to a vertebrate liver, diverticulates here, as does the pancreas, and both of these empty into the caecum, a pouch-shaped sac where most of the absorption of nutrients takes place. Indigestible food can be passed directly from the stomach to the rectum where it joins the flow from the caecum and is voided through the anus into the mantle cavity. Cephalopods are short-lived, and in mature squid, priority is given to reproduction; the female Onychoteuthis banksii for example, sheds its feeding tentacles on reaching maturity, and becomes flaccid and weak after spawning.
CARDIOVASCULAR AND EXCRETORY SYSTEMS
The squid mantle cavity is a seawater-filled sac containing three hearts and other organs supporting circulation, respiration, and excretion. Squid have a main systemic heart that pumps blood around the body as part of the general circulatory system, and two branchial hearts. The systemic heart consists of three chambers, a lower ventricle and two upper atria, all of which can contract to propel the blood. The branchial hearts pump blood specifically to the gills for oxygenation, before returning it to the systemic heart. The blood contains the copper-rich protein hemocyanin, which is used for oxygen transport at low ocean temperatures and low oxygen concentrations, and makes the oxygenated blood a deep, blue color. As systemic blood returns via two vena cavae to the branchial hearts, excretion of urine, carbon dioxide, and waste solutes occurs through outpockets (called nephridial appendages) in the vena cavae walls that enable gas exchange and excretion via the mantle cavity seawater.
BUOYANCY
Unlike nautiloids which have gas-filled chambers inside their shells which provide buoyancy, and octopuses which live near and rest on the seabed and do not require to be buoyant, many squid have a fluid-filled receptacle, equivalent to the swim bladder of a fish, in the coelom or connective tissue. This reservoir acts as a chemical buoyancy chamber, with the heavy metallic cations typical of seawater replaced by low molecular-weight ammonium ions, a product of excretion. The small difference in density provides a small contribution to buoyancy per unit volume, so the mechanism requires a large buoyancy chamber to be effective. Since the chamber is filled with liquid, it has the advantage over a swim bladder of not changing significantly in volume with pressure. Glass squids in the family Cranchiidae for example, have an enormous transparent coelom containing ammonium ions and occupying about two-thirds the volume of the animal, allowing it to float at the required depth. About half of the 28 families of squid use this mechanism to solve their buoyancy issues.
LARGEST AND SMALLEST
The majority of squid are no more than 60 cm long, although the giant squid may reach 13 m. The smallest species are probably the benthic pygmy squids Idiosepius, which grow to a mantle length of 10 to 18 mm, and have short bodies and stubby arms.
In 1978, sharp, curved claws on the suction cups of squid tentacles cut up the rubber coating on the hull of the USS Stein. The size suggested the largest squid known at the time.
In 2003, a large specimen of an abundant but poorly understood species, Mesonychoteuthis hamiltoni (the colossal squid), was discovered. This species may grow to 10 m in length, making it the largest invertebrate. In February 2007, a New Zealand fishing vessel caught the largest squid ever documented, weighing 495 kg and measuring around 10 m off the coast of Antarctica. Dissection showed that the eyes, used to detect prey in the deep Southern Ocean, exceeded the size of footballs; these may be among the largest eyes ever to exist in the animal kingdom.
DEVELOPMENT
The eggs of squid are large for a mollusc, containing a large amount of yolk to nourish the embryo as it develops directly, without an intervening veliger larval stage. The embryo grows as a disc of cells on top of the yolk. During the gastrulation stage, the margins of the disc grow to surround the yolk, forming a yolk sac, which eventually forms part of the animal's gut. The dorsal side of the disc grows upwards and forms the embryo, with a shell gland on its dorsal surface, gills, mantle and eyes. The arms and funnel develop as part of the foot on the ventral side of the disc. The arms later migrate upwards, coming to form a ring around the funnel and mouth. The yolk is gradually absorbed as the embryo grows. Some juvenile squid live higher in the water column than do adults. Squids tend to be short-lived; Loligo for example lives from one to three years according to species, typically dying soon after spawning.
n a well-studied bioluminescent species, the Hawaiian bobtail squid, a special light organ in the squid's mantle is rapidly colonized with Aliivibrio fischeri bacteria within hours of hatching. This light-organ colonization requires this particular bacterial species for a symbiotic relationship; no colonization occurs in the absence of A. fischeri. Colonization occurs in a horizontal manner, such that the hosts acquires its bacterial partners from the environment. The symbiosis is obligate for the squid, but facultative for the bacteria. Once the bacteria enter the squid, they colonize interior epithelial cells in the light organ, living in crypts with complex microvilli protrusions. The bacteria also interact with hemocytes, macrophage-like blood cells that migrate between epithelial cells, but the mechanism and function of this process is not well understood. Bioluminescence reaches its highest levels during the early evening hours and bottoms out before dawn; this occurs because at the end of each day, the contents of the squid's crypts are expelled into the surrounding environment. About 95% of the bacteria are voided each morning before the bacterial population builds up again by nightfall.
BEHAVIOUR
LOCOMOTION
Squid can move about in several different ways. Slow movement is achieved by a gentle undulation of the muscular lateral fins on either side of the trunk which drives the animal forward. A more common means of locomotion providing sustained movement is achieved using jetting, during which contraction of the muscular wall of the mantle cavity provides jet propulsion.
Slow jetting is used for ordinary locomotion, and ventilation of the gills is achieved at the same time. The circular muscles in the mantle wall contract; this causes the inhalant valve to close, the exhalant valve to open and the mantle edge to lock tightly around the head. Water is forced out through the funnel which is pointed in the opposite direction to the required direction of travel. The inhalant phase is initiated by the relaxation of the circular muscles causes them to stretch, the connective tissue in the mantle wall recoils elastically, the mantle cavity expands causing the inhalant valve to open, the exhalant valve to close and water to flow into the cavity. This cycle of exhalation and inhalation is repeated to provide continuous locomotion.
Fast jetting is an escape response. In this form of locomotion, radial muscles in the mantle wall are involved as well as circular ones, making it possible to hyper-inflate the mantle cavity with a larger volume of water than during slow jetting. On contraction, water flows out with great force, the funnel always being pointed anteriorly, and travel is backwards. During this means of locomotion, some squid exit the water in a similar way to flying fish, gliding through the air for up to 50 m, and occasionally ending up on the decks of ships.
FEEDING
Squid are carnivores, and, with their strong arms and suckers, can overwhelm relatively large animals efficiently. Prey is identified by sight or by touch, grabbed by the tentacles which can be shot out with great rapidity, brought back to within reach of the arms, and held by the hooks and suckers on their surface. In some species, the squid's saliva contains toxins which act to subdue the prey. These are injected into its bloodstream when the prey is bitten, along with vasodilators and chemicals to stimulate the heart, and quickly circulate to all parts of its body. The deep sea squid Taningia danae has been filmed releasing blinding flashes of light from large photophores on its arms to illuminate and disorientate potential prey.
Although squid can catch large prey, the mouth is relatively small, and the food must be cut into pieces by the chitinous beak with its powerful muscles before being swallowed. The radula is located in the buccal cavity and has multiple rows of tiny teeth that draw the food backwards and grind it in pieces. The deep sea squid Mastigoteuthis has the whole length of its whip-like tentacles covered with tiny suckers; it probably catches small organisms in the same way that flypaper traps flies. The tentacles of some bathypelagic squids bear photophores which may bring food within its reach by attracting prey.
Squid are among the most intelligent invertebrates. For example, groups of Humboldt squid hunt cooperatively, spiralling up through the water at night and coordinating their vertical and horizontal movements while foraging.
REPRODUCTION
Courtship in squid takes place in the open water and involves the male selecting a female, the female responding, and the transfer by the male of spermatophores to the female. In many instances, the male may display to identify himself to the female and drive off any potential competitors.[46] Elaborate changes in body patterning take place in some species in both agonistic and courtship behaviour. The Caribbean reef squid (Sepioteuthis sepioidea), for example, employs a complex array of colour changes during courtship and social interactions and has a range of about 16 body patterns in its repertoire.
The pair adopt a head-to-head position, and "jaw locking" may take place, in a similar manner to that adopted by some cichlid fish. The heterodactylus of the male is used to transfer the spermatophore and deposit it in the female's mantle cavity in the position appropriate for the species; this may be adjacent to the gonopore or in a seminal receptacle.
The sperm may be used immediately or may be stored. As the eggs pass down the oviduct, they are wrapped in a gelatinous coating, before continuing to the mantle cavity, where they are fertilised. In Loligo, further coatings are added by the nidimental glands in the walls of the cavity and the eggs leave through a funnel formed by the arms. The female attaches them to the substrate in strings or groups, the coating layers swelling and hardening after contact with sea water. Loligo sometimes forms breeding aggregations which may create a "community pile" of egg strings. Some pelagic and deep sea squid do not attach their egg masses, which float freely.
ECOLOGY
Squid mostly have an annual life cycle, growing fast and dying soon after spawning. The diet changes as they grow but mostly consists of large zooplankton and small nekton. In Antarctica for example, krill is the main constituent of the diet, with other food items being amphipods, other small crustaceans, and large arrow worms. Fish are also eaten, and some squid are cannibalistic.
As well as occupying a key role in the food chain, squid are an important prey for predators including sharks, sea birds, seals and whales. Juvenile squid provide part of the diet for worms and small fish. When researchers studied the contents of the stomachs of elephant seals in South Georgia, they found 96% squid by weight. In a single day, a sperm whale can eat 700 to 800 squid, and a Risso's dolphin entangled in a net in the Mediterranean was found to have eaten angel clubhook squid, umbrella squid, reverse jewel squid and European flying squid, all identifiable from their indigestible beaks. Ornithoteuthis volatilis, a common squid from the tropical Indo-Pacific, is predated by yellowfin tuna, longnose lancetfish, common dolphinfish and swordfish, the tiger shark, the scalloped hammerhead shark and the smooth hammerhead shark. Sperm whales also hunt this species extensively as does the brown fur seal. In the Southern Ocean, penguins and wandering albatrosses are major predators of Gonatus antarcticus.
HUMAN USES
IN LITERATUR AND ART
Giant squid have featured as monsters of the deep since classical times. Giant squid were described by Aristotle (4th century BC) in his History of Animals and Pliny the Elder (1st century AD) in his Natural History. The Gorgon of Greek mythology may have been inspired by squid or octopus, the animal itself representing the severed head of Medusa, the beak as the protruding tongue and fangs, and its tentacles as the snakes. The six-headed sea monster of the Odyssey, Scylla, may have had a similar origin. The Nordic legend of the kraken may also have derived from sightings of large cephalopods.
In literature, H. G. Wells' short story "The Sea Raiders" featured a man-eating squid species Haploteuthis ferox.[59] The science fiction writer Jules Verne told a tale of a kraken-like monster in his 1870 novel Twenty Thousand Leagues Under the Sea.
AS FOOD
Squid form a major food resource and are used in cuisines around the world, notably in Japan where it is eaten as ika sōmen, sliced into vermicelli-like strips; as sashimi; and as tempura. Three species of Loligo are used in large quantities, L. vulgaris in the Mediterranean (known as Calamar in Spanish, Calamaro in Italian); L. forbesii in the Northeast Atlantic; and L. pealei on the American East Coast. Among the Ommastrephidae, Todarodes pacificus is the main commercial species, harvested in large quantities across the North Pacific in Canada, Japan and China.
In English-speaking countries, squid as food is often called calamari, adopted from Italian into English in the 17th century. Squid are found abundantly in certain areas, and provide large catches for fisheries. The body can be stuffed whole, cut into flat pieces, or sliced into rings. The arms, tentacles, and ink are also edible; the only parts not eaten are the beak and gladius (pen). Squid is a good food source for zinc and manganese, and high in copper, selenium, vitamin B12, and riboflavin.
COMMERCIAL FISHING
According to the FAO, the cephalopod catch for 2002 was 3,173,272 tonnes. Of this, 2,189,206 tonnes, or 75.8 percent, was squid. The following table lists squid species fishery catches that exceeded 10,000 tonnes in 2002.
IN BIOMIMICRY
Prototype chromatophores that mimic the squid's adaptive camouflage, have been made by Bristol University researchers using an electroactive dielectric elastomer, a flexible "smart" material that changes its colour and texture in response to electrical signals. The researchers state that their goal is to create an artificial skin that provides rapid active camouflage.
The squid giant axon inspired Otto Schmitt to develop a comparator circuit with hysteresis now called the Schmitt trigger, replicating the axon's propagation of nerve impulses.
WIKIPEDIA
Alexander bodied X reg Dennis Dominator, beautifully restored internally and wearing a commemorative livery celebrating Doncaster Corporation's undertakings prior to South Yorkshire PTE's absorption.
Metro
Beijing, China
July 2012
Candid shots in and around Public Transport
Ricoh GRD IV
Please do not reproduce or use this picture without my explicit permission.
If you ask nicely I will probably say yes, just ask me first!
If you happen to be in one of my frames and have any objections to this.
Please contact me!
Please no glossy awards, scripted comments and big thumbnails back to your own work.
I will remove them...
Backlit Beauties in Ophiuchus
Credit: Giuseppe Donatiello
A dark nebula or absorption nebula is a type of interstellar cloud, particularly molecular clouds, that is so dense that it obscures the visible wavelengths of light from objects behind it, such as background stars and emission or reflection nebulae.
Dark clouds appear so because of sub-micrometre-sized dust particles, coated with frozen carbon monoxide and nitrogen, which effectively block the passage of light at visible wavelengths.
The main molecular clouds are annotated according to SIMBAD.
Square crop of a wider field obtained with the Tair-3S array (300mm f/4.5) during the 2023 astronomical camp.
- sports car
- street-level parking lot
- artificially colored mulch
- plastic tarp preventing absorption of rain water
gimme a break.
Amsterdam
June 2012
The Netherlands
Urban life in the Netherlands
Ricoh GRD IV
Please do not reproduce or use this picture without my explicit permission.
If you ask nicely I will probably say yes, just ask me first!
If you happen to be in one of my frames and have any objections to this.
Please contact me!
Please no glossy awards, scripted comments and big thumbnails back to your own work.
I will remove them..
Two versions of a sketch of the visual spectrum of the setting Sun showing the prominent telluric lines towards the red end.
The bottom spectrum shows lines in black and diffuse bands in grey as they would appear in the spectroscope.
In the top spectrum, the telluric features are coded in blue (for water vapour absorption), red (for diatomic oxygen) and brown (for tetra-oxygen).
A few of the strong Solar Fraunhofer lines are shown in black and marked with their designations (C – h) in black letters.
Greek(alpha) marks the combination of ordinary diatomic oxygen absorption and a broader contribution from the collisionally induced transition in the transitory association of two oxygen molecules called tetra-oxygen. Greek(delta) marks the strongest visible tetra-oxygen absorption at ~576nm.
'r' marks the water absorption that was known in the late nineteenth century as The Rainband since there were attempts to use it as a predictor of rain.
These three features along with the water band that encompasses the H-alpha line 'Fraunhofer C' are the most visually prominent telluric features.
I find it interesting that two of these features are associated with an absorption process that was not identified until 1949 ( en.wikipedia.org/wiki/Collision-induced_absorption_and_em... ).
The 19th century scientists had appreciated that these two bands behaved differently from the water absorptions and became stronger more rapidly as the Sun approached the horizon. However, they had no idea what caused them.
The yellow gap between r and delta appears as a very prominent structure in the visible spectrum of the daytime sky, particularly at dusk and dawn.. The yellow almost looks as if it is an emission band superimposed on the Solar spectrum!
The coloured background spectrum in these illustrations is derived from my own photograph, taken with a full-spectrum digital camera, of a dispersed quartz-halogen lamp using a slit and a 60° glass prism.
The word Allah
The Semitic language which is spoken in the celestial spheres, is the language in which the angels and God address each other. Adam Safi-Allah spoke the same language in paradise. Adam and eve then came into the world and settled in Arabia. Their children also spoke the same language. Then as a result of the descendants of Adam spreading in the world, this language passed from Arabic, Persian, Latin and into English and God was then known by different names in the different languages. As Adam lived in Arabia, there are many words of the Semitic language which are still found in the Arabic language. God addressed the Prophets, Adam as Adam Safi-Allah, Noah as Nuh Nabi-Allah, Abraham as Ibraheem Khalil-Allah, Moses as Musa Kalim-Allah, Jesus as I’sa Ruh-Allah and Mohammed Rasul-Allah. All these titles, in the Semitic language were written on the Tablet before the arrival of the Prophets. This is why the Prophet Mohammed said: “I was a Prophet even before I came in to this world.”
Many people believe that the word Allah is a name given by Muslims, this is not so.
The Prophet Mohammed’s fathers name was Abd-Allah, at a time when Islam did not exist. Prior to the advent of Islam the Name Allah was announced with the title of every Prophet. When the souls were created, the first Name on their tongue was Allah and when the soul entered the body of Adam, it said, Ya-Allah, and only then it entered the body. Many religions understand this enigma and chant the Name Allah and many others because of doubt are deprived of the Name.
Any name which is used to point towards God is worthy of respect.
In other words, which points towards God. The mystical effect of the Name of God has been diversified due to the different names. Every letter of the alphabet has a separate numeric value. This is also a celestial knowledge. All the numeric values are connected with all of the human race. Occasionally the numeric values do not agree with the astronomical calculations as a result of which people become afflicted. Many people go to astrologers and experts of this knowledge and have charts prepared based on the stars. They name their children on this basis.
Just as the letters (a, b, j, d,) (1, 2, 3, 4) when added have the numerical value of ten. Similarly every name has a separate numeric value. As God has been given so many different names, this has caused a conflict between the numeric value of the different names. If all the people called upon God by the same name, then despite the fact that they would all have separate religions, they would all be united inwardly. They too, like Nanak Sahib and Baba Farid would then say:
“All the souls have been created by the light of God, even though their environment and communities are separate.”
The angels that are assigned tasks in the world are also taught the languages of the people of the world.
It is important for the people of every Prophet that they recite, chant and affirm the Title of their Prophet which was granted by God to the Prophet at his time, for the recognition, spiritual grace and purification of his people. The recital and affirmation should be in the same method and in the language of their Prophet.
The entry of any individual into any religion is subject to the condition that the individual accepts and affirms the Title of the Prophet of that religion. Just as the affirmation and the verbal vows are a condition of any marriage.
Entry into the heavens has been made subject to the acceptance and affirmation of the Titles of the Prophets. In the western world many Muslims and Christians have no knowledge of their Prophet’s Title furthermore many do not even know their Prophets original name (in the original language of the Prophet.)
People who only verbalize the affirmation of their Prophet’s Title rely upon their good deeds. Those that reject and do not affirm their Prophet’s Title are refused entry to paradise. Those individuals in whose hearts the affirmation of their Prophet’s Title has descended (entered) they will enter paradise without any accountability.
The revealed celestial Scriptures, whichever language they are in so long as they are in the original form, are a means to finding God. Where the texts and the translations that have been adulterated, just as adulterated flour is harmful for the stomach, the adulterated books have become harmful and people of the same religion and the same of Prophet have divided into so many sects.
To be sure of the straight and guided path it is better that you are guided by the Light (of God) also.
The method of producing light.
In prehistoric times stones would be rubbed together to make fire. Whereas a spark can also be produced by rubbing two metals together. In a similar way electricity is made from water. Similarly by the friction of the blood inside the human body, in other words electric energy is produced by the vibrating heartbeat. In every human being there is present, approximately one and a half volts of electricity due to which the body is energetic. As the heartbeat slows in old age, this reduces the electricity in the body and this in turn also causes a reduction of the energy level in the body.
Firstly, the heartbeat has to be made vibrant and pronounced. Some do this by dancing, some by sports and exercise and some people try to do this by meditating and chanting the Name of God Allah.
When the heartbeat becomes vibrant and pronounced then by chanting the Name Allah try to synchronize it with every heartbeat. Alternatively try to synchronize Allah with one heartbeat and Hu with the other. Some time by placing your hand on the heart and when you feel your heartbeat, again try to synchronize the Name Allah by chanting it with the rythm of the heartbeat and imagine that the Name Allah is entering the heart.
The chanting of Allah Hu is better and more effective but if anyone has an objection, or a fear of chanting Hu, then instead of being deprived one should solely use the Name Allah, repetitively in the chanting. It is beneficial for people who chant and practice this discipline and who read mantras to physically remain as clean as possible as the:
“disrespectful are unfulfilled and the respectful are fulfilled.”
The first method for producing light.
Write Allah on a paper in black ink, and do this exercise for as long as you wish on a daily basis. Soon thereafter, the Word Allah will be transported from the paper and hover over the eyes. Then with one-pointed concentration, attempt to transport the word from the eyes to the heart.
The second method for producing light.
Write Allah on a zero watt bulb, in yellow. Whilst you are awake or just before sleep, concentrate and try to absorb it into the eyes. When it appears on the eyes then try to transport it to the heart.
The third method for producing light.
This method is for those people who have perfect spiritual guides and teachers and who due to their spiritual connection are spiritually assisted by them.
Sit alone and imagine that your index finger is a pen. Using your finger and with your concentration, attempt to write Allah on your heart. Call upon your spiritual teacher (spiritually), so that he too may, hold your finger, and write Allah on your heart. Continue to do this exercise everyday, until you see Allah written on your heart.
By the first and second method, the Name Allah becomes inscribed on the heart, just as it was written and seen by you but when it becomes synchronized with the heartbeat, then it slowly starts to shine. In the synchronized method, the assistance of the spiritual teacher is provided and for this reason it is seen shining and well written on the heart right from the beginning.
Many Prophets and Saints have come into the world, and just for the sake of testing this, if you feel it appropriate, concentrate or call upon all of them when you are practicing your meditation.
Whilst concentrating on any Prophet or Saint, during your meditating practice, if the rhythm of your heartbeat increases, in its vibration or you feel an improvement then this means that your destiny (spiritual fruits) lies with that Prophet or Saint.
Thereafter it is beneficial to concentrate on that same person whenever you practice your meditation as spiritual grace is transferred in this way, because every Saint is spiritually connected to a Prophet, even if that Prophet is not physically living.
The spiritual fruit (grace) of every illuminated person is in the hands of one Saint or another. It is essential that the Saint is living. Sometimes a very fortunate person is gifted with celestial spiritual grace by a perfect Saint who is not living, but this is very rare. However Saints not living in our human realm can provide worldly spiritual grace and assistance to people from their tombs. This is known as Owaisi spiritual grace.
The recipients of such spiritual grace often get entangled in their spiritual insights, visions and dreams because the spiritual guide providing the assistance is in the spiritual realm and so too is Satan and the recognition of the two becomes difficult.
Along with the spiritual grace it is important to have knowledge, for which a living Saint is more appropriate. If a person (Saint) possesses spiritual grace but is without knowledge, that person is known as a Majzoob (Godly but abstracted due to the complete absorption into the Essence of God and who is not in full control of his faculties).
A person (Saint) having spiritual grace and knowledge is known as a Mehboob (literally, loved one). Such people (Saints) as a result of their knowledge provide worldly spiritual assistance as well as spiritual grace and benefit. Whereas the Majzoobs are known to provide worldly spiritual assistance to people by their unusual but accepted practices of shouting obscenities and poking people with their wooden sticks.
If any (Prophet or Saint) appears but does not help or assist you then put Gohar Shahi to the test.
You may belong to any religion, there is no condition in this respect as long as the individual is not eternally ill-fated.
Many people have received the spiritual grace of Qalb meditation from the Moon. This is obtained when there is a full Moon from the East. Look at it with concentration and when you see the image of Gohar Shahi on it say Allah, Allah, Allah three times and you will be blessed with this spiritual grace. Thereafter without any fear or reservation practice the meditation as described.
Believe (the fact) that the image on the Moon has spoken to many people in many different languages. You can try looking and speaking to it also.
About Muraqba
(transcendental meditation)
(Literally. journey. Meditation in which the soul leaves the human body)
Many people without having acquired the illumination of the spiritual entities (‘Lata’if/Shaktian’) and without attaining spiritual strength and prowess try to engage in this meditation. They either fail to reach the meditative state or become the subject of Satanic interference. This type of meditation is for illuminated people, whose spiritual entity of the self has been purified and the Qalb has been cleansed. The practice or attempt at this type of meditation is foolish no matter what type of physical worship is used to achieve this. To collect and gather the strength of the soul and the spiritual entities and then to travel to a place is what is known as meditation.
Sainthood is the one fourtieth part of Prophecy.
Every dream, meditative journey, inspiration or revelation of a Prophet is accurate and authentic and does not need verification. Only fourty out of a hundred dreams, meditative journeys, inspirations and revelations of Saints are accurate the remaining sixty percent are inaccurate.
God cannot be understood without knowledge
The lowest type of meditative journey is started only after the illumination and awakening of the spiritual entity of the Qalb. This is impossible without first achieving the meditation of the Qalb (meditation with the vibrating heartbeat synchronized with the Name Allah). It takes one jerk or shake to bring the person out of this meditative state and back to consciousness. The faculty of the augury (foretelling the future by reading verses or looking into designated books) is also connected to the Qalb.
The next stage is the meditative journey of the soul. It takes three jerks or shakes to return a person back to normality from this meditative state.
The third stage of the meditative journey is done by the spiritual entity, Anna and the soul together. The soul travels along with the spiritual entity Anna, to the realm of souls just as the Archangel Gabriel accompanied the Prophet Mohammed to the realm of souls.
People who are in this meditative state are sometimes even taken to be buried in their graves and they are unaware of this happening to them. Such a meditative state and journey was taken by the “Companions of the Cave” as a result of which they remained asleep in the cave for more than three hundred years.
When this meditative state and journey was undertaken by the Sheikh, Abdul-Qadir al-Jilani, in the jungle, the occupants of the jungle would regard the Sheikh as dead and would take him to a grave for burial but the meditative journey would break just before the burial (the Sheikh would return to consciousness).
How to recognize a special inspiration and revelation from God.
When a person has awakened and illuminated the spiritual entities in the chest and is worthy of receiving the rays of the Grace of God, then at that point God communicates with that person. God is All-Powerful and can do as he pleases and thus communicate with the human being in any way fit, but he has made a special method for his recognition so that his friends can be saved from the deception of Satan.
Firstly, text in the Semitic language appears on the seekers heart and its translation is seen in the language of the seekers mother-tongue. The text is white and shiny and the eyes close automatically and look at the text (internally). The text then passes the Qalb and moves towards the spiritual entity Sirri as a result of which it shines even more. Then the text moves towards the spiritual entity, Akhfa and from here it shines more and then moves onto the tongue. The voice then spontaneously starts to repeat that text.
If this inspiration is from Satan then an illuminated heart will dull the text and if the text is strong and prominent then the spiritual entities Sirri or Akhfa destroy that text. Further if due to the weakness of the spiritual entities the text does arrive at the tongue, then the voice will prevent it from being spoken into words.
This type of inspiration is for special types of Saints, whereas in respect of ordinary Saints, God sends messages to them through the angels or other spiritual entities. When the Archangel Gabriel accompanies the special and inspired text, this is known as revelation which is confined to the Prophets.
For more detail visit www.goharshahi.org or visit asipk.com and for videos visit HH rags
Infrared converted Sony A6000 with Tokina AT-X 116 Pro DX lens. HDR AEB +/-2 total of 3 exposures at F8, 11mm, manual focus and processed with Photomatix HDR software.
High Dynamic Range (HDR)
High-dynamic-range imaging (HDRI) is a high dynamic range (HDR) technique used in imaging and photography to reproduce a greater dynamic range of luminosity than is possible with standard digital imaging or photographic techniques. The aim is to present a similar range of luminance to that experienced through the human visual system. The human eye, through adaptation of the iris and other methods, adjusts constantly to adapt to a broad range of luminance present in the environment. The brain continuously interprets this information so that a viewer can see in a wide range of light conditions.
HDR images can represent a greater range of luminance levels than can be achieved using more 'traditional' methods, such as many real-world scenes containing very bright, direct sunlight to extreme shade, or very faint nebulae. This is often achieved by capturing and then combining several different, narrower range, exposures of the same subject matter. Non-HDR cameras take photographs with a limited exposure range, referred to as LDR, resulting in the loss of detail in highlights or shadows.
The two primary types of HDR images are computer renderings and images resulting from merging multiple low-dynamic-range (LDR) or standard-dynamic-range (SDR) photographs. HDR images can also be acquired using special image sensors, such as an oversampled binary image sensor.
Due to the limitations of printing and display contrast, the extended luminosity range of an HDR image has to be compressed to be made visible. The method of rendering an HDR image to a standard monitor or printing device is called tone mapping. This method reduces the overall contrast of an HDR image to facilitate display on devices or printouts with lower dynamic range, and can be applied to produce images with preserved local contrast (or exaggerated for artistic effect).
In photography, dynamic range is measured in exposure value (EV) differences (known as stops). An increase of one EV, or 'one stop', represents a doubling of the amount of light. Conversely, a decrease of one EV represents a halving of the amount of light. Therefore, revealing detail in the darkest of shadows requires high exposures, while preserving detail in very bright situations requires very low exposures. Most cameras cannot provide this range of exposure values within a single exposure, due to their low dynamic range. High-dynamic-range photographs are generally achieved by capturing multiple standard-exposure images, often using exposure bracketing, and then later merging them into a single HDR image, usually within a photo manipulation program). Digital images are often encoded in a camera's raw image format, because 8-bit JPEG encoding does not offer a wide enough range of values to allow fine transitions (and regarding HDR, later introduces undesirable effects due to lossy compression).
Any camera that allows manual exposure control can make images for HDR work, although one equipped with auto exposure bracketing (AEB) is far better suited. Images from film cameras are less suitable as they often must first be digitized, so that they can later be processed using software HDR methods.
In most imaging devices, the degree of exposure to light applied to the active element (be it film or CCD) can be altered in one of two ways: by either increasing/decreasing the size of the aperture or by increasing/decreasing the time of each exposure. Exposure variation in an HDR set is only done by altering the exposure time and not the aperture size; this is because altering the aperture size also affects the depth of field and so the resultant multiple images would be quite different, preventing their final combination into a single HDR image.
An important limitation for HDR photography is that any movement between successive images will impede or prevent success in combining them afterwards. Also, as one must create several images (often three or five and sometimes more) to obtain the desired luminance range, such a full 'set' of images takes extra time. HDR photographers have developed calculation methods and techniques to partially overcome these problems, but the use of a sturdy tripod is, at least, advised.
Some cameras have an auto exposure bracketing (AEB) feature with a far greater dynamic range than others, from the 3 EV of the Canon EOS 40D, to the 18 EV of the Canon EOS-1D Mark II. As the popularity of this imaging method grows, several camera manufactures are now offering built-in HDR features. For example, the Pentax K-7 DSLR has an HDR mode that captures an HDR image and outputs (only) a tone mapped JPEG file. The Canon PowerShot G12, Canon PowerShot S95 and Canon PowerShot S100 offer similar features in a smaller format.. Nikon's approach is called 'Active D-Lighting' which applies exposure compensation and tone mapping to the image as it comes from the sensor, with the accent being on retaing a realistic effect . Some smartphones provide HDR modes, and most mobile platforms have apps that provide HDR picture taking.
Camera characteristics such as gamma curves, sensor resolution, noise, photometric calibration and color calibration affect resulting high-dynamic-range images.
Color film negatives and slides consist of multiple film layers that respond to light differently. As a consequence, transparent originals (especially positive slides) feature a very high dynamic range
Tone mapping
Tone mapping reduces the dynamic range, or contrast ratio, of an entire image while retaining localized contrast. Although it is a distinct operation, tone mapping is often applied to HDRI files by the same software package.
Several software applications are available on the PC, Mac and Linux platforms for producing HDR files and tone mapped images. Notable titles include
Adobe Photoshop
Aurora HDR
Dynamic Photo HDR
HDR Efex Pro
HDR PhotoStudio
Luminance HDR
MagicRaw
Oloneo PhotoEngine
Photomatix Pro
PTGui
Information stored in high-dynamic-range images typically corresponds to the physical values of luminance or radiance that can be observed in the real world. This is different from traditional digital images, which represent colors as they should appear on a monitor or a paper print. Therefore, HDR image formats are often called scene-referred, in contrast to traditional digital images, which are device-referred or output-referred. Furthermore, traditional images are usually encoded for the human visual system (maximizing the visual information stored in the fixed number of bits), which is usually called gamma encoding or gamma correction. The values stored for HDR images are often gamma compressed (power law) or logarithmically encoded, or floating-point linear values, since fixed-point linear encodings are increasingly inefficient over higher dynamic ranges.
HDR images often don't use fixed ranges per color channel—other than traditional images—to represent many more colors over a much wider dynamic range. For that purpose, they don't use integer values to represent the single color channels (e.g., 0-255 in an 8 bit per pixel interval for red, green and blue) but instead use a floating point representation. Common are 16-bit (half precision) or 32-bit floating point numbers to represent HDR pixels. However, when the appropriate transfer function is used, HDR pixels for some applications can be represented with a color depth that has as few as 10–12 bits for luminance and 8 bits for chrominance without introducing any visible quantization artifacts.
History of HDR photography
The idea of using several exposures to adequately reproduce a too-extreme range of luminance was pioneered as early as the 1850s by Gustave Le Gray to render seascapes showing both the sky and the sea. Such rendering was impossible at the time using standard methods, as the luminosity range was too extreme. Le Gray used one negative for the sky, and another one with a longer exposure for the sea, and combined the two into one picture in positive.
Mid 20th century
Manual tone mapping was accomplished by dodging and burning – selectively increasing or decreasing the exposure of regions of the photograph to yield better tonality reproduction. This was effective because the dynamic range of the negative is significantly higher than would be available on the finished positive paper print when that is exposed via the negative in a uniform manner. An excellent example is the photograph Schweitzer at the Lamp by W. Eugene Smith, from his 1954 photo essay A Man of Mercy on Dr. Albert Schweitzer and his humanitarian work in French Equatorial Africa. The image took 5 days to reproduce the tonal range of the scene, which ranges from a bright lamp (relative to the scene) to a dark shadow.
Ansel Adams elevated dodging and burning to an art form. Many of his famous prints were manipulated in the darkroom with these two methods. Adams wrote a comprehensive book on producing prints called The Print, which prominently features dodging and burning, in the context of his Zone System.
With the advent of color photography, tone mapping in the darkroom was no longer possible due to the specific timing needed during the developing process of color film. Photographers looked to film manufacturers to design new film stocks with improved response, or continued to shoot in black and white to use tone mapping methods.
Color film capable of directly recording high-dynamic-range images was developed by Charles Wyckoff and EG&G "in the course of a contract with the Department of the Air Force". This XR film had three emulsion layers, an upper layer having an ASA speed rating of 400, a middle layer with an intermediate rating, and a lower layer with an ASA rating of 0.004. The film was processed in a manner similar to color films, and each layer produced a different color. The dynamic range of this extended range film has been estimated as 1:108. It has been used to photograph nuclear explosions, for astronomical photography, for spectrographic research, and for medical imaging. Wyckoff's detailed pictures of nuclear explosions appeared on the cover of Life magazine in the mid-1950s.
Late 20th century
Georges Cornuéjols and licensees of his patents (Brdi, Hymatom) introduced the principle of HDR video image, in 1986, by interposing a matricial LCD screen in front of the camera's image sensor, increasing the sensors dynamic by five stops. The concept of neighborhood tone mapping was applied to video cameras by a group from the Technion in Israel led by Dr. Oliver Hilsenrath and Prof. Y.Y.Zeevi who filed for a patent on this concept in 1988.
In February and April 1990, Georges Cornuéjols introduced the first real-time HDR camera that combined two images captured by a sensor3435 or simultaneously3637 by two sensors of the camera. This process is known as bracketing used for a video stream.
In 1991, the first commercial video camera was introduced that performed real-time capturing of multiple images with different exposures, and producing an HDR video image, by Hymatom, licensee of Georges Cornuéjols.
Also in 1991, Georges Cornuéjols introduced the HDR+ image principle by non-linear accumulation of images to increase the sensitivity of the camera: for low-light environments, several successive images are accumulated, thus increasing the signal to noise ratio.
In 1993, another commercial medical camera producing an HDR video image, by the Technion.
Modern HDR imaging uses a completely different approach, based on making a high-dynamic-range luminance or light map using only global image operations (across the entire image), and then tone mapping the result. Global HDR was first introduced in 19931 resulting in a mathematical theory of differently exposed pictures of the same subject matter that was published in 1995 by Steve Mann and Rosalind Picard.
On October 28, 1998, Ben Sarao created one of the first nighttime HDR+G (High Dynamic Range + Graphic image)of STS-95 on the launch pad at NASA's Kennedy Space Center. It consisted of four film images of the shuttle at night that were digitally composited with additional digital graphic elements. The image was first exhibited at NASA Headquarters Great Hall, Washington DC in 1999 and then published in Hasselblad Forum, Issue 3 1993, Volume 35 ISSN 0282-5449.
The advent of consumer digital cameras produced a new demand for HDR imaging to improve the light response of digital camera sensors, which had a much smaller dynamic range than film. Steve Mann developed and patented the global-HDR method for producing digital images having extended dynamic range at the MIT Media Laboratory. Mann's method involved a two-step procedure: (1) generate one floating point image array by global-only image operations (operations that affect all pixels identically, without regard to their local neighborhoods); and then (2) convert this image array, using local neighborhood processing (tone-remapping, etc.), into an HDR image. The image array generated by the first step of Mann's process is called a lightspace image, lightspace picture, or radiance map. Another benefit of global-HDR imaging is that it provides access to the intermediate light or radiance map, which has been used for computer vision, and other image processing operations.
21st century
In 2005, Adobe Systems introduced several new features in Photoshop CS2 including Merge to HDR, 32 bit floating point image support, and HDR tone mapping.
On June 30, 2016, Microsoft added support for the digital compositing of HDR images to Windows 10 using the Universal Windows Platform.
HDR sensors
Modern CMOS image sensors can often capture a high dynamic range from a single exposure. The wide dynamic range of the captured image is non-linearly compressed into a smaller dynamic range electronic representation. However, with proper processing, the information from a single exposure can be used to create an HDR image.
Such HDR imaging is used in extreme dynamic range applications like welding or automotive work. Some other cameras designed for use in security applications can automatically provide two or more images for each frame, with changing exposure. For example, a sensor for 30fps video will give out 60fps with the odd frames at a short exposure time and the even frames at a longer exposure time. Some of the sensor may even combine the two images on-chip so that a wider dynamic range without in-pixel compression is directly available to the user for display or processing.
en.wikipedia.org/wiki/High-dynamic-range_imaging
Infrared Photography
In infrared photography, the film or image sensor used is sensitive to infrared light. The part of the spectrum used is referred to as near-infrared to distinguish it from far-infrared, which is the domain of thermal imaging. Wavelengths used for photography range from about 700 nm to about 900 nm. Film is usually sensitive to visible light too, so an infrared-passing filter is used; this lets infrared (IR) light pass through to the camera, but blocks all or most of the visible light spectrum (the filter thus looks black or deep red). ("Infrared filter" may refer either to this type of filter or to one that blocks infrared but passes other wavelengths.)
When these filters are used together with infrared-sensitive film or sensors, "in-camera effects" can be obtained; false-color or black-and-white images with a dreamlike or sometimes lurid appearance known as the "Wood Effect," an effect mainly caused by foliage (such as tree leaves and grass) strongly reflecting in the same way visible light is reflected from snow. There is a small contribution from chlorophyll fluorescence, but this is marginal and is not the real cause of the brightness seen in infrared photographs. The effect is named after the infrared photography pioneer Robert W. Wood, and not after the material wood, which does not strongly reflect infrared.
The other attributes of infrared photographs include very dark skies and penetration of atmospheric haze, caused by reduced Rayleigh scattering and Mie scattering, respectively, compared to visible light. The dark skies, in turn, result in less infrared light in shadows and dark reflections of those skies from water, and clouds will stand out strongly. These wavelengths also penetrate a few millimeters into skin and give a milky look to portraits, although eyes often look black.
Until the early 20th century, infrared photography was not possible because silver halide emulsions are not sensitive to longer wavelengths than that of blue light (and to a lesser extent, green light) without the addition of a dye to act as a color sensitizer. The first infrared photographs (as distinct from spectrographs) to be published appeared in the February 1910 edition of The Century Magazine and in the October 1910 edition of the Royal Photographic Society Journal to illustrate papers by Robert W. Wood, who discovered the unusual effects that now bear his name. The RPS co-ordinated events to celebrate the centenary of this event in 2010. Wood's photographs were taken on experimental film that required very long exposures; thus, most of his work focused on landscapes. A further set of infrared landscapes taken by Wood in Italy in 1911 used plates provided for him by CEK Mees at Wratten & Wainwright. Mees also took a few infrared photographs in Portugal in 1910, which are now in the Kodak archives.
Infrared-sensitive photographic plates were developed in the United States during World War I for spectroscopic analysis, and infrared sensitizing dyes were investigated for improved haze penetration in aerial photography. After 1930, new emulsions from Kodak and other manufacturers became useful to infrared astronomy.
Infrared photography became popular with photography enthusiasts in the 1930s when suitable film was introduced commercially. The Times regularly published landscape and aerial photographs taken by their staff photographers using Ilford infrared film. By 1937 33 kinds of infrared film were available from five manufacturers including Agfa, Kodak and Ilford. Infrared movie film was also available and was used to create day-for-night effects in motion pictures, a notable example being the pseudo-night aerial sequences in the James Cagney/Bette Davis movie The Bride Came COD.
False-color infrared photography became widely practiced with the introduction of Kodak Ektachrome Infrared Aero Film and Ektachrome Infrared EIR. The first version of this, known as Kodacolor Aero-Reversal-Film, was developed by Clark and others at the Kodak for camouflage detection in the 1940s. The film became more widely available in 35mm form in the 1960s but KODAK AEROCHROME III Infrared Film 1443 has been discontinued.
Infrared photography became popular with a number of 1960s recording artists, because of the unusual results; Jimi Hendrix, Donovan, Frank and a slow shutter speed without focus compensation, however wider apertures like f/2.0 can produce sharp photos only if the lens is meticulously refocused to the infrared index mark, and only if this index mark is the correct one for the filter and film in use. However, it should be noted that diffraction effects inside a camera are greater at infrared wavelengths so that stopping down the lens too far may actually reduce sharpness.
Most apochromatic ('APO') lenses do not have an Infrared index mark and do not need to be refocused for the infrared spectrum because they are already optically corrected into the near-infrared spectrum. Catadioptric lenses do not often require this adjustment because their mirror containing elements do not suffer from chromatic aberration and so the overall aberration is comparably less. Catadioptric lenses do, of course, still contain lenses, and these lenses do still have a dispersive property.
Infrared black-and-white films require special development times but development is usually achieved with standard black-and-white film developers and chemicals (like D-76). Kodak HIE film has a polyester film base that is very stable but extremely easy to scratch, therefore special care must be used in the handling of Kodak HIE throughout the development and printing/scanning process to avoid damage to the film. The Kodak HIE film was sensitive to 900 nm.
As of November 2, 2007, "KODAK is preannouncing the discontinuance" of HIE Infrared 35 mm film stating the reasons that, "Demand for these products has been declining significantly in recent years, and it is no longer practical to continue to manufacture given the low volume, the age of the product formulations and the complexity of the processes involved." At the time of this notice, HIE Infrared 135-36 was available at a street price of around $12.00 a roll at US mail order outlets.
Arguably the greatest obstacle to infrared film photography has been the increasing difficulty of obtaining infrared-sensitive film. However, despite the discontinuance of HIE, other newer infrared sensitive emulsions from EFKE, ROLLEI, and ILFORD are still available, but these formulations have differing sensitivity and specifications from the venerable KODAK HIE that has been around for at least two decades. Some of these infrared films are available in 120 and larger formats as well as 35 mm, which adds flexibility to their application. With the discontinuance of Kodak HIE, Efke's IR820 film has become the only IR film on the marketneeds update with good sensitivity beyond 750 nm, the Rollei film does extend beyond 750 nm but IR sensitivity falls off very rapidly.
Color infrared transparency films have three sensitized layers that, because of the way the dyes are coupled to these layers, reproduce infrared as red, red as green, and green as blue. All three layers are sensitive to blue so the film must be used with a yellow filter, since this will block blue light but allow the remaining colors to reach the film. The health of foliage can be determined from the relative strengths of green and infrared light reflected; this shows in color infrared as a shift from red (healthy) towards magenta (unhealthy). Early color infrared films were developed in the older E-4 process, but Kodak later manufactured a color transparency film that could be developed in standard E-6 chemistry, although more accurate results were obtained by developing using the AR-5 process. In general, color infrared does not need to be refocused to the infrared index mark on the lens.
In 2007 Kodak announced that production of the 35 mm version of their color infrared film (Ektachrome Professional Infrared/EIR) would cease as there was insufficient demand. Since 2011, all formats of color infrared film have been discontinued. Specifically, Aerochrome 1443 and SO-734.
There is no currently available digital camera that will produce the same results as Kodak color infrared film although the equivalent images can be produced by taking two exposures, one infrared and the other full-color, and combining in post-production. The color images produced by digital still cameras using infrared-pass filters are not equivalent to those produced on color infrared film. The colors result from varying amounts of infrared passing through the color filters on the photo sites, further amended by the Bayer filtering. While this makes such images unsuitable for the kind of applications for which the film was used, such as remote sensing of plant health, the resulting color tonality has proved popular artistically.
Color digital infrared, as part of full spectrum photography is gaining popularity. The ease of creating a softly colored photo with infrared characteristics has found interest among hobbyists and professionals.
In 2008, Los Angeles photographer, Dean Bennici started cutting and hand rolling Aerochrome color Infrared film. All Aerochrome medium and large format which exists today came directly from his lab. The trend in infrared photography continues to gain momentum with the success of photographer Richard Mosse and multiple users all around the world.
Digital camera sensors are inherently sensitive to infrared light, which would interfere with the normal photography by confusing the autofocus calculations or softening the image (because infrared light is focused differently from visible light), or oversaturating the red channel. Also, some clothing is transparent in the infrared, leading to unintended (at least to the manufacturer) uses of video cameras. Thus, to improve image quality and protect privacy, many digital cameras employ infrared blockers. Depending on the subject matter, infrared photography may not be practical with these cameras because the exposure times become overly long, often in the range of 30 seconds, creating noise and motion blur in the final image. However, for some subject matter the long exposure does not matter or the motion blur effects actually add to the image. Some lenses will also show a 'hot spot' in the centre of the image as their coatings are optimised for visible light and not for IR.
An alternative method of DSLR infrared photography is to remove the infrared blocker in front of the sensor and replace it with a filter that removes visible light. This filter is behind the mirror, so the camera can be used normally - handheld, normal shutter speeds, normal composition through the viewfinder, and focus, all work like a normal camera. Metering works but is not always accurate because of the difference between visible and infrared refraction. When the IR blocker is removed, many lenses which did display a hotspot cease to do so, and become perfectly usable for infrared photography. Additionally, because the red, green and blue micro-filters remain and have transmissions not only in their respective color but also in the infrared, enhanced infrared color may be recorded.
Since the Bayer filters in most digital cameras absorb a significant fraction of the infrared light, these cameras are sometimes not very sensitive as infrared cameras and can sometimes produce false colors in the images. An alternative approach is to use a Foveon X3 sensor, which does not have absorptive filters on it; the Sigma SD10 DSLR has a removable IR blocking filter and dust protector, which can be simply omitted or replaced by a deep red or complete visible light blocking filter. The Sigma SD14 has an IR/UV blocking filter that can be removed/installed without tools. The result is a very sensitive digital IR camera.
While it is common to use a filter that blocks almost all visible light, the wavelength sensitivity of a digital camera without internal infrared blocking is such that a variety of artistic results can be obtained with more conventional filtration. For example, a very dark neutral density filter can be used (such as the Hoya ND400) which passes a very small amount of visible light compared to the near-infrared it allows through. Wider filtration permits an SLR viewfinder to be used and also passes more varied color information to the sensor without necessarily reducing the Wood effect. Wider filtration is however likely to reduce other infrared artefacts such as haze penetration and darkened skies. This technique mirrors the methods used by infrared film photographers where black-and-white infrared film was often used with a deep red filter rather than a visually opaque one.
Another common technique with near-infrared filters is to swap blue and red channels in software (e.g. photoshop) which retains much of the characteristic 'white foliage' while rendering skies a glorious blue.
Several Sony cameras had the so-called Night Shot facility, which physically moves the blocking filter away from the light path, which makes the cameras very sensitive to infrared light. Soon after its development, this facility was 'restricted' by Sony to make it difficult for people to take photos that saw through clothing. To do this the iris is opened fully and exposure duration is limited to long times of more than 1/30 second or so. It is possible to shoot infrared but neutral density filters must be used to reduce the camera's sensitivity and the long exposure times mean that care must be taken to avoid camera-shake artifacts.
Fuji have produced digital cameras for use in forensic criminology and medicine which have no infrared blocking filter. The first camera, designated the S3 PRO UVIR, also had extended ultraviolet sensitivity (digital sensors are usually less sensitive to UV than to IR). Optimum UV sensitivity requires special lenses, but ordinary lenses usually work well for IR. In 2007, FujiFilm introduced a new version of this camera, based on the Nikon D200/ FujiFilm S5 called the IS Pro, also able to take Nikon lenses. Fuji had earlier introduced a non-SLR infrared camera, the IS-1, a modified version of the FujiFilm FinePix S9100. Unlike the S3 PRO UVIR, the IS-1 does not offer UV sensitivity. FujiFilm restricts the sale of these cameras to professional users with their EULA specifically prohibiting "unethical photographic conduct".
Phase One digital camera backs can be ordered in an infrared modified form.
Remote sensing and thermographic cameras are sensitive to longer wavelengths of infrared (see Infrared spectrum#Commonly used sub-division scheme). They may be multispectral and use a variety of technologies which may not resemble common camera or filter designs. Cameras sensitive to longer infrared wavelengths including those used in infrared astronomy often require cooling to reduce thermally induced dark currents in the sensor (see Dark current (physics)). Lower cost uncooled thermographic digital cameras operate in the Long Wave infrared band (see Thermographic camera#Uncooled infrared detectors). These cameras are generally used for building inspection or preventative maintenance but can be used for artistic pursuits as well.