What is the function of a densitometer in film processing QC?

• A. To calibrate X-ray exposure settings
• B. To measure the density of processed film to ensure consistent density
• C. To measure the strength of developing chemicals
• D. To assess patient dose

Answer: (C)

The main idea is to quantify how dark the processed radiographic film is, using optical density measurements. In film processing QC, a densitometer reads the density of processed film so you can ensure those readings stay within a target range. This provides a numeric check on image brightness and contrast across multiple films, helping you catch changes in processor performance—like shifts in developer strength, temperature, or chemical replenishment—that could alter density. By comparing readings against a reference, you maintain consistent image quality. It isn’t used to calibrate exposure settings, measure chemical strength directly, or assess patient dose, which are handled by other QC checks and tools.