Orthochromatic photographic emulsion

Description

A light-sensitive gelatin emulsion for coating any support: paper, glass, wood, fabric, metal. Orthochromatic, so it can be handled under a red safelight.

What it is for

Warm it in a water bath, brush or pour it on, dry it in the dark — and you have your own photographic material in any shape. After that it is an ordinary silver-gelatin process: enlarger or contact exposure, developer, fixer, wash.

What orthochromatic means

The emulsion is blind to red, so the whole process can be done under a red safelight where you can see what you are doing. The trade-off is the tonal rendering: reds print dark and blues light.

Questions and answers

Does the support need sizing?

For paper and wood, preferably — otherwise the emulsion soaks in unevenly. Glass is degreased; a gelatin subbing layer makes adhesion reliable.