Definition & Meaning of "developing tank"

What is a "developing tank"?

A developing tank is a container used in photographic processing to hold film or photographic paper while it is treated with chemicals. It keeps the material completely covered and protected from light during development, allowing for consistent chemical action. The tank typically has a lid to prevent light from entering and may include reels or holders to keep the film or paper in place. Developing tanks are essential for processing film and paper in both black-and-white and color photography.