Can blue-light-emitting screens be used with green-sensitive film?

• A. True
• B. False
• C. Not specified
• D. Depends on film

Answer: (B)

Blue light does not properly expose green-sensitive film. Film emulsions are tuned to respond to specific wavelengths, and green-sensitive film is designed to respond to green light (roughly in the 500–550 nm range). Blue-emitting screens put out light mainly in the blue region (around 450 nm). When you illuminate green-sensitive film with blue light, the photons aren’t in the film’s sensitive range, so the latent image won’t form properly and the radiographic image will be underexposed or undeveloped. To use blue-emitting screens, you’d need blue-sensitive film or a screen that matches the film’s spectral sensitivity.