What is measured by a sensitometric strip?

• A. fog
• B. speed
• C. contrast
• D. 1, 2 and 3

Answer: (D)

A sensitometric strip is used to characterize how a radiographic film responds to exposure across a range, capturing the baseline density, sensitivity, and the density range produced. It measures three things: fog (the base plus any background density when there’s no useful exposure), speed (how much exposure is needed to reach a defined density, reflecting the film’s sensitivity), and contrast (the slope of the density vs exposure curve, indicating how sharply densities change with exposure). Because it provides data on all three aspects, it gives a comprehensive assessment of film performance. If you looked at only one aspect—for example, fog alone—you’d miss how the film responds to exposure overall, including how quickly it reaches useful densities and how well it differentiates between levels of exposure.