What should be done if yellow/brown stains appear on processed films?

The appearance of yellow or brown stains on processed films typically indicates an issue with the chemical processing of the films, specifically related to the developer or fixer solutions used. When old or depleted chemicals are present in the processing bath, they may no longer effectively function, leading to incomplete processing that manifests as staining.

Replacing old chemicals ensures that the processing solutions maintain their proper activity levels, contributing to clean and well-defined images. Fresh chemicals are crucial for adequate development and fixing of the film, which results in optimal image quality and prevents the formation of unwanted stains.

In contrast, increasing washing time would generally address issues related to residual chemicals, but if the developer or fixer is old or ineffective, washing time alone would not rectify the root cause of the staining. Decreasing developing temperature might produce different results, but it does not address the quality of the processing chemicals. Using a different film type can also lead to different processing outcomes, but it is more of a workaround than a solution to the underlying problem of chemical efficacy.