Civil War era CDV Photo Cards Portraits males. Photos taken in private studios.  In order to finance the war, the Union government instituted the Revenue Act of 1862, which taxed luxury items such as photographs. Photographers were required to collect tax for each image and to show the tax was paid by affixing a stamp to the back and cancelling it with their initials and date. On August 1, 1866 the tax on photography was repealed, making these photos with revenue stamps indicative of the Civil War era. They do not appear on images prior to or after the war, making them easy to date.