Glossary of Printing Terms:
Fogging

Darkening or discoloring of a negative or print or lightening or discoloring of a slide caused by

1. Exposure to nonimage-forming light to which the photographic material is sensitive,

2. Too much handling in air during development,

3. Over-development,

4. Outdated film or paper, or

5. Storage of film or paper in a hot, humid place.