This chemically developed silver chloride or chlorobromide paper used the first contact-speed emulsion fast enough to be printed by gaslight. The colloquial description persisted into the 1930s, by which time electricity was the dominant artificial light source, and ‘gaslight’ signalled the paper's relative slowness in comparison with bromide papers. Manufactured from the early 1880s, usage was limited until the introduction of Velox paper in 1893. Most papers had gelatin emulsions, although a collodion variant was current from 1895 into the 1910s. Gaslight paper was inexpensive and easy to handle; it was popular for contact-printed photographs until the 1960s, when the supremacy of 35 mm negatives made enlarging paper imperative.
— Hope Kingsley
