Safelights used in the darkroom should typically be of what wattage?

• A. 15-watt
• B. 10-watt
• C. 20-watt
• D. 25-watt

Answer: (A)

Safelights in the darkroom are chosen to give enough visibility to handle film without exposing or fogging the emulsion. X-ray film is sensitive to blue/green light, so a red safelight with a proper filter provides illumination in a long-wavelength range that the film won’t react to. The wattage matters because it sets how bright that safe light will be. A 15-watt safelight hits the sweet spot: it’s bright enough to see what you’re doing but not so bright that stray light can fog the film during processing. Higher wattages would increase the risk of fogging, while lower wattages could make handling and viewing film awkward. So, the standard choice is a 15-watt safelight.