Freshly exposed sensitometric strip should be read with which device?

• A. Densitometer
• B. Caliper
• C. Spectrophotometer
• D. Thermometer

Answer: (A)

The question tests how we quantify radiographic film exposure. A sensitometric strip is used to generate a known range of exposures on film so we can assess how the film responds after processing. To read that strip accurately, you need a densitometer. A densitometer measures optical density—the amount of light the film blocks when illuminated by a fixed light source at a specific wavelength. By converting that transmitted light into a density value, it gives precise, repeatable readings across the exposure steps, which you use to build the sensitometry (H&D) curve and evaluate film processing and exposure consistency.

Calipers measure physical dimensions, which don’t tell you anything about the film’s density. A spectrophotometer can assess light absorption, but densitometry is the specialized, calibrated method for radiographic film densities and accepts the film’s typical density ranges and wavelengths. A thermometer measures temperature, unrelated to density readings.