Most of the photos on this site were extracted from reference images (high-resolution tiffs, 20 to 200 megabytes in size) from the Library of Congress research archive. (To query the database click here.) Many were digitized by LOC contractors using a Sinar studio back. They are adjusted by your webmaster for contrast and color in Photoshop before being downsized and turned into the jpegs you see here.
1865. "Petersburg, Virginia. Sections of chevaux-de-frise before Confederate main works." From photographs of the main Eastern theater of war, the siege of Petersburg, June 1864-April 1865. Glass plate negative, left half of stereograph pair, from Civil War photos compiled by Milhollen and Mugridge. View full size.