athiril
Gas Bleaching Test #1
First test after I happed to found a bottle of sulphuric acid in a random box of chemicals from vanbar I was given. Score. Wish I looked closely instead of spending weeks lamenting about a lack of sulphuric acid.
Anyway, there were two dark small circles on the film from 2 drops of rodinal placed on it, then washed off.
The circle mark is the bleaching area, I generated chlorine gas in a erlenmeyer flask and place the film over it to let chlorine gas pass against the surface.
Bleached pretty quick, so that part of the film is silver chloride (chlorine displaces bromine in salts, as it's the more reactive halogen).
Now I can get onto gas bleaching some Kodak Gold 100 (10 years expired, actually terribly grainy and shitty overexposed and pulled!) that I left in the sun to reduce to a finer grain silver, that I can bleach back with bromine fumes.
Should be fine grain, slow and sharp, and high contrast.
With no silver iodide on the film (bromine will displace it), I suspect it will develop very fast in regular C-41 process, may need a special low contrast dev, or C-41 at room temp.
Should be able to gas bleach (in the dark) dodgy old expired film with iodine fumes to restore speed, or gain speed on top of box speed depending on the emulsion type, we'll see.
Gas Bleaching Test #1
First test after I happed to found a bottle of sulphuric acid in a random box of chemicals from vanbar I was given. Score. Wish I looked closely instead of spending weeks lamenting about a lack of sulphuric acid.
Anyway, there were two dark small circles on the film from 2 drops of rodinal placed on it, then washed off.
The circle mark is the bleaching area, I generated chlorine gas in a erlenmeyer flask and place the film over it to let chlorine gas pass against the surface.
Bleached pretty quick, so that part of the film is silver chloride (chlorine displaces bromine in salts, as it's the more reactive halogen).
Now I can get onto gas bleaching some Kodak Gold 100 (10 years expired, actually terribly grainy and shitty overexposed and pulled!) that I left in the sun to reduce to a finer grain silver, that I can bleach back with bromine fumes.
Should be fine grain, slow and sharp, and high contrast.
With no silver iodide on the film (bromine will displace it), I suspect it will develop very fast in regular C-41 process, may need a special low contrast dev, or C-41 at room temp.
Should be able to gas bleach (in the dark) dodgy old expired film with iodine fumes to restore speed, or gain speed on top of box speed depending on the emulsion type, we'll see.