Scratches on films are caused by:

• A. Over-development
• B. Insufficient washing
• C. Dirty crossover rollers
• D. Thio retention

Answer: (C)

Scratches on radiographic films come from mechanical damage as the film moves through the processor. The crossover rollers guide the film from one path to another, and if those rollers are dirty or have rough surfaces, they can contact the emulsion and leave fine, parallel scratches along the film. Keeping the crossover rollers clean and in good condition prevents this type of artifact.

Other processing problems change density, contrast, or chemical residues but don’t create surface scratches in the emulsion. Over-development dulls or darkens areas, insufficient washing leaves residues or stains, and thio retention involves fixer-related issues affecting clearing rather than making scratches.