A warped cassette produces what type of unsharpness on finished radiographs?

• A. Global
• B. Localized
• C. Uniform
• D. Random

Answer: (B)

Unsharpness in radiography is driven by geometry, and sharpness depends on keeping the film plane parallel to the beam with consistent object-to-film distances. A warped cassette disrupts that flat, parallel relationship, so the film sits at different distances from the object across the field and may not lie evenly against the screen. This variation creates blur in specific regions where the geometry is off, giving you localized unsharpness. It’s not a uniform blur across the entire image, which would suggest a single global factor like a consistently large focal spot or a uniform increase in object-to-film distance. The warp produces patches of blur where the geometry changes, hence the localized pattern of unsharpness.