1. to expose beforehand or in advance
Usage: transitive verb; technical/specialized usage in photography and printing
2. to subject to preliminary exposure (as to light, radiation, or a substance) before a main or final exposure
Usage: transitive verb; used in photography, printing, and scientific contexts

Examples

• The photographer decided to preexpose the film to reduce contrast in the final image.
• In the printing process, the plate was preexposed to ultraviolet light.
• The technician preexposed the photographic paper to ensure even development.
• Preexposing the substrate improved the adhesion of the coating.
• The experimental protocol required preexposing the samples to low-level radiation before the main treatment.