Bull Run. Bridge near Union Mills (destroyed seven times)
Timothy H. O'Sullivan (American, born Ireland, 1840–1882)
Hundreds of photographers whose names may never be known made their living following the armies during the Civil War. They worked out in the field tents and traveled at a moment’s notice. Photographers recorded the faces of tens of thousands of soldiers: new recruits and veterans—producing a vast likeness of American society. Many Civil War photographers began their careers as apprentices to Mathew B. Brady, America's self-appointed photographic "historian." Initially, a small corps of photographers copied maps and charts for the Union's Secret Service, which were distributed as photographic prints to both field and division commanders. During the Civil War, most photographers worked with the collodion-on-glass negatives, which required delicate and laborious procedures even in the studio. When the photographer was ready for action, a sheet of glass was cleaned, coated with collodion, partially dried, dipped carefully into a bath containing nitrate of silver, then exposed in the camera for several seconds and processed in the field darkroom tent--all before the silver collodion mixture had dried. Given the danger of their situation and the technical difficulty of their task, front-line photographers rarely if ever attempted action scenes. Civil War photographers produced vast photographic documentation of the Civil War. Despite decades of painstaking research by dedicated historians and Civil War buffs, a large number of the era's photographs remain unidentified.