Underexpose (verb)

To subject to less light or radiation than is necessary for proper exposure.

Origin:

From un- (not) + expose (to subject to light or radiation).

Examples:

1. The photographer underexposed the image and the subject appeared too dark.
2. He underexposed the film, resulting in a weak image.
3. I underexposed the photograph because I thought it would make the background stand out more.
4. The camera underexposed the shot, making the subject appear too dark.
5. The film was underexposed, resulting in an image that was too dark.