Orthochromatic Photography
Orthochromatic photography refers to a photographic emulsion that is sensitive to only blue and green light, and thus can be processed with a red safelight. The increased blue sensitivity causes blue objects to appear lighter and red ones darker. A cyan lens filter—which removes red light—can be used with standard panchromatic film to produce a similar effect.
Orthochromatic films were first produced by Hermann Wilhelm Vogel in 1873 by adding small amounts of certain aniline-based dyes to photographic emulsions which had thitherto been sensitive to blue light only. This work was extended by others including Josef Maria Eder, who introduced the use of the red dye erythrosine in 1884.
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Famous quotes containing the word photography:
“If photography is allowed to stand in for art in some of its functions it will soon supplant or corrupt it completely thanks to the natural support it will find in the stupidity of the multitude. It must return to its real task, which is to be the servant of the sciences and the arts, but the very humble servant, like printing and shorthand which have neither created nor supplanted literature.”
—Charles Baudelaire (1821–1867)