Photographs

Photographs and other visual media convey historical information in a uniquely immediate way, but their use as evidence requires careful analysis. Not only should the historian consider the usual who, what, when, where, and why, but also issues such as the photographer's choice of perspective, framing, and distance from subject.

The dating of photographs requires the historian to know something about the history of photographic processes in order to be able to distinguish daguerreotypes, ambrotypes, tintypes, paper prints, albumen prints, etc. from more recent photographic processes.