Which photographic process was a precursor to modern photography that required long exposure times?

The calotype process is indeed a precursor to modern photography and is significant because it was one of the first techniques to produce images on paper and allowed for the creation of negative photographs. Developed by William Henry Fox Talbot in the 1830s, the calotype utilized a paper coated with silver iodide, which would react to light when exposed. This process required long exposure times, often several minutes to hours, depending on the lighting conditions. The ability to make multiple positive prints from a single negative was a revolutionary step in the evolution of photography, leading to the more versatile and widely used processes that came afterward.

In contrast, digital photography represents a completely different technological advancement, utilizing sensors and electronic storage rather than chemical reactions to capture images. Techniques like tintypes also involve shorter exposure times than calotypes and were more immediate in terms of development. Additionally, DSLR (Digital Single-Lens Reflex) cameras are modern photographic equipment that leverages digital technology, and thus are not related to historical processes. The calotype's emphasis on long exposure times and its role in the foundation of photography makes it the correct choice for this question.