Purple Emperor
I only managed one purple wing from this angle but I still think it looks pretty stunning. As you move the iridescent purple bounces from wing to wing. The name Purple Emperor has been in use since the middle of the eighteenth century. I think it was Benjamin Wilkes who first coined the name in 1741 for this butterfly. Purple was a very difficult colour to produce and in Japan the colour was traditionally only worn by Emperors and the top aristocracy so I'm assuming this was behind Wilkes' name. But the colour purple in this butterfly is not a pigment but an optical illusion created by the microstructure of the wing scales. The colour created by a thin transparent coating on each wing scale where light reflects off both the front and back of this layer, creating "interference colours" rather like the colours you see on a puddle when a microscopically thin layer of oil is on the surface. I photographed this male in Fermyn Woods, Northants a couple of weeks back.
Purple Emperor
I only managed one purple wing from this angle but I still think it looks pretty stunning. As you move the iridescent purple bounces from wing to wing. The name Purple Emperor has been in use since the middle of the eighteenth century. I think it was Benjamin Wilkes who first coined the name in 1741 for this butterfly. Purple was a very difficult colour to produce and in Japan the colour was traditionally only worn by Emperors and the top aristocracy so I'm assuming this was behind Wilkes' name. But the colour purple in this butterfly is not a pigment but an optical illusion created by the microstructure of the wing scales. The colour created by a thin transparent coating on each wing scale where light reflects off both the front and back of this layer, creating "interference colours" rather like the colours you see on a puddle when a microscopically thin layer of oil is on the surface. I photographed this male in Fermyn Woods, Northants a couple of weeks back.