What results in white spots on film during processing?

When fixer contacts the film before it has been properly processed, it results in the formation of white spots on the developed film. This occurs because the fixer, which is intended to remove unexposed silver halide crystals from the film, can prematurely cause the areas that are exposed to it to appear white once the film is fully developed. The fixer's chemical action contrasts with the developer, which creates the darker areas by reducing the exposed crystals.

Other factors such as old developer, static electricity, and air bubbles can lead to various issues during film development, but they do not specifically result in white spots. Old developer may fail to produce a proper image or may result in a fogged appearance, while static electricity can create lines or spots that do not resemble the distinct white spots caused by premature fixer contact. Air bubbles can trap unexposed film areas, but they would usually create irregular patterns rather than uniform white spots. Hence, the correct identification of fixer contact as the cause highlights the importance of proper handling during the processing stages to ensure a clear and accurate film outcome.