Tag: photography
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Albumen prints and egg whites…all the rage back in the day…and a few other things
The albumen print, also called albumen silver print, was published in January 1847 by Louis DĂ©sirĂ© Blanquart-Evrard, and was the first commercially exploitable method of producing a photographic print on a paper base from a negative. It used the albumen found in egg whites to bind the photographic chemicals to the paper and became the dominant form of photographic positives from 1855 to the start…
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p-Phenylenediamine (PPD) is a derivative of aniline used in kevlar, hair dye and henna substitutions among other things, the derivatives of which are used in antiozonants among other horrors
p-Phenylenediamine (PPD) is an organic compound with the formula C6H4(NH2)2. This derivative of aniline is a white solid, but samples can darken due to air oxidation.It is mainly used as a component of engineering polymers and composites like kevlar. It is also an ingredient in hair dyes and is occasionally used as a substitute for henna. Production PPD is produced via three routes. Most commonly, 4-nitrochlorobenzene is treated…
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Lumiflavin and Lumichrome notes (and something called Autochrome)
Lumiflavin is a toxic product of photolysis of vitamin B2. Lumiflavin is a compound showing yellow-green fluorescence, formed by a photolysis of riboflavin in alkaline solution. Lumiflavin 1948-Present Lumichrome 1944-Present The Autochrome Lumière was an early color photography process patented in 1903 by the Lumière brothers in France and first marketed in 1907. Autochrome was an additive color “mosaic screen plate” process. It was the principal color photography process in use before the…
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4-Aminophenol – what a molecule!
This is a humble organic compound with the formula H2NC6H4OH, but don’t let its unassuming structure fool you. This is not just any crystalline powder; this is a chemical that moonlights as a pharmaceutical ingredient, a hair dye precursor, and—wait for it—a black-and-white film developer. If molecules had rĂ©sumĂ©s, 4-Aminophenol’s would read like someone who’s worked…
