Safelights

Part of speech: noun

Definitions

1. A lamp used in a darkroom that emits light of a wavelength that does not expose photographic film or light-sensitive materials
2. A darkroom fixture that produces illumination in a color and intensity that will not affect undeveloped photographic emulsions
3. A specially filtered lamp that provides visible light in a darkroom without fogging or damaging film and other light-sensitive photographic materials

Etymology: Photographic film and paper are sensitive to light, so a darkroom needs a light that will not fog them. Early photographers mostly used dark red or amber lamps, because the emulsions of their day responded weakly to those colours. The word describes a light that is safe only relative to a particular material. The same lamp would ruin film sensitive to red, which later emulsions were. The first part, "safe," comes from Old French "sauf," from Latin "salvus," meaning uninjured or whole, so the sense is "not harmful." "Light" is the ordinary Old English word. The compound is a plain descriptive one, coined to name a specific piece of darkroom equipment.