Orange (colour) paint straight from the tube. Paul Cézanne did not use orange pigment, but created his own oranges with touches of yellow, red and ochre against a blue background. Toulouse-Lautrec often used oranges in the skirts of dancers and gowns of Parisiennes in the cafes and clubs he portrayed. For him it was the colour of festivity and amusement. The post-impressionists went even further with orange. Paul Gauguin used oranges as backgrounds, for clothing and skin colour, to fill his pictures with light and exoticism. But no other painter used orange so often and dramatically as Vincent van Gogh. who had
Photosynthetic pigment other groups of bacteria use the bacteriochlorophyll pigments (similar to the chlorophylls) for photosynthesis. Unlike the cyanobacteria, these bacteria do not produce oxygen; they typically use hydrogen sulfide rather than water as the electron donor. Recently, a very different pigment has been found in some marine γ-proteobacteria: proteorhodopsin. It is similar to and probably originated from bacteriorhodopsin (see below: under Archaea). Bacterial chlorophyll b has been isolated from Rhodopseudomonas spp. but its structure is not yet known to us. Halobacteria use the pigment bacteriorhodopsin which acts directly as a proton pump when exposed to light. Photosynthetic pigment A photosynthetic pigment