What is the cause of white spots on a processed film?

Question

Quizplus · Accepted Answer

If the fixer contacts the film prior to processing, it can cause white spots on the processed film. This is because fixer is designed to dissolve away undeveloped silver halide crystals, which create the image on the film. If fixer contacts the film before development, it can remove these crystals and result in white spots. Static electricity, warm solutions, and drops of developer may cause other types of defects on a processed film, but not specifically white spots.

What Is the Cause of White Spots on a Processed