In a dental darkroom, safelight is used to handle x-ray film. Which color safelight is appropriate?

• A. Red
• B. Blue
• C. Green
• D. White

Answer: (A)

Choosing a safelight color is about preventing fogging of the film while still giving you enough light to work. X-ray film emulsions are sensitive to blue and green wavelengths, so you need a safelight that minimizes exposure to those colors. Red safelight provides long-wavelength illumination that the film is not sensitive to, so it allows handling the film without fogging. Blue or green safelights emit wavelengths that would fog the film and degrade image quality, and white light would fog it instantly. Therefore, red safelight is appropriate for the dental darkroom.