Scratches on films are caused by which of the following?

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

Answer: (A)

Scratches on film come from a mechanical source in the processor, specifically the crossover rollers. When these rollers are dirty or contaminated with grit, the film surface can be abraded as it passes between tanks, creating fine, parallel scratch lines on the emulsion. This type of artifact is physical damage to the emulsion, not a chemical issue, so it’s best explained by dirty rollers.

Over-development changes overall density and contrast, not the surface integrity of the film. Thio retention and insufficient washing cause chemical artifacts or staining from residual processing chemicals, not scratches. Keeping crossover rollers clean and properly aligned prevents this mechanical scratching and maintains a smooth path for the film.