Bromide Paper: Gelatino-Bromide Emulsion Coated on Paper

Bromide paper is paper coated with silver bromide in gelatin, the printing and enlarging paper of the darkroom. Thorpe (1913) gives a beginner's emulsion: gelatin swelled in potassium bromide solution, silver nitrate made clear with strong ammonia, the two joined under ruby light, ripened, set, washed, and spread on paper as on a glass plate. From the moment the silver goes in, work only by ruby light. Grain and ounce figures are Thorpe's; the gram conversions and the 10-sheet batch are ours. The picture: our own drawing.