What is the performance criterion for the darkroom fog test?

What is the performance criterion for the darkroom fog test?

• A. Less than .01 increase in density in 2 minutes
• B. Less than .05 increase in density in 2 minutes
• C. Less than .1 increase in density in 5 minutes
• D. No change in density

Answer: (C)

The test checks safelight compatibility by measuring how much fog the safelight causes on unexposed film during a typical processing cycle. The performance criterion is that the increase in optical density from fog should be less than 0.1 when the film is exposed to the safelight for a 5-minute interval. If the density rises by more than 0.1, the safelight is contributing unacceptable fog and could degrade image quality. This 0.1 density limit over five minutes provides a practical threshold that accounts for typical processing, while acknowledging that some minor fog can occur but must stay under this level.

The test checks safelight compatibility by measuring how much fog the safelight causes on unexposed film during a typical processing cycle. The performance criterion is that the increase in optical density from fog should be less than 0.1 when the film is exposed to the safelight for a 5-minute interval. If the density rises by more than 0.1, the safelight is contributing unacceptable fog and could degrade image quality. This 0.1 density limit over five minutes provides a practical threshold that accounts for typical processing, while acknowledging that some minor fog can occur but must stay under this level.