The Civil War was the first great media event in American history, and the first war to be thoroughly documented using the emerging medium of photography. The daguerreotype – an image on silver-plated copper – had been introduced in 1839. That technique required a long exposure time and was used largely to produce portraits in studios. Twenty years later, a new development called the wet-plate process reduced exposure time and allowed multiple prints to be made from a single glass-plate negative. Photography still involved cumbersome and expensive equipment, but that did not stop enterprising cameramen from loading their gear on wagons and documenting events as they unfolded.
The leading photographer in America in 1861 was Mathew Brady. His New York studio dominated the field. People of influence had their portraits taken by Brady. Abraham Lincoln sat for him several times.