What happens to the contrast of a black-and-white negative with a longer development time?

When a black-and-white negative undergoes a longer development time, the contrast of the image increases, resulting in darker areas of the negative. This happens because during the development process, exposed silver halide crystals are converted to metallic silver. A longer development time allows more of these crystals, particularly those in the more exposed areas of the film, to be reduced, leading to a higher density in those regions.

Consequently, the darker areas appear more pronounced, effectively increasing the overall contrast of the image. Areas that received less exposure may also be affected, resulting in a more substantial difference between the darkest and lightest parts of the photograph. The result is a negative that displays stronger tonal differences, providing a more dynamic range when printed.

In contrast, shorter development times typically lead to lower contrast, as fewer silver crystals are developed, resulting in more mid-tone representation rather than deep blacks or bright whites. This understanding of the relationship between development time and contrast is crucial for photographers aiming to achieve specific aesthetic qualities in their black-and-white prints.