Safelights

Safelights are low-intensity light sources used in photographic darkrooms to illuminate working areas without fogging or exposing light-sensitive materials. They enable operators to handle paper, film, and chemistry while maintaining a usable working environment.

Most safelights emit long-wavelength red or amber light, typically in the 620 to 700 nanometer range. In traditional black-and-white photography, a common arrangement uses a small incandescent bulb behind a deep red filter, such as a Wratten 6B or similar, providing enough visibility at low brightness. Some laboratories now use LED safelights that filter to pass only very narrow, long wavelengths to minimize any risk of fogging.

Color materials are more sensitive to red light, and safelights are generally avoided when handling color films or papers. Exposure to safelights can fog silver halide emulsions or dye layers if the time or intensity is excessive, reducing contrast and image quality. When safelights are used with color materials, specialized filters or tested procedures are required, and many workflows rely on complete darkness for color work.

Modern darkrooms may employ LED safelights, filtered incandescent lamps, or safelight boxes. It is common practice to test safelight suitability for a given material by exposing a sample under the safelight for a known period and developing it to determine safe handling times.

See also: darkroom, photographic paper, film development.