Póster Lt General Ulysses S Grant

Lt. General Ulysses S. Grant standing by a tree in front of a tent in Cold Harbor, Va., June 1864. Ulysses S. Grant[ (born Hiram Ulysses Grant]) (April 27, 1822 – July 23, 1885) was general-in-chief of the Union Army from 1864 to 1865 during the American Civil War and the 18th President of the United States from 1869 to 1877. Vintage photo from a daguerreotype which was a direct-positive process, creating a highly detailed image on a sheet of copper plated with a thin coat of silver without the use of a negative. The process required great care. The silver-plated copper plate had first to be cleaned and polished until the surface looked like a mirror. Next, the plate was sensitized in a closed box over iodine until it took on a yellow-rose appearance. The plate, held in a lightproof holder, was then transferred to the camera. After exposure to light, the plate was developed over hot mercury until an image appeared. To fix the image, the plate was immersed in a solution of sodium thiosulfate or salt and then toned with gold chloride. Exposure times for the earliest daguerreotypes ranged from three to fifteen minutes, making the process nearly impractical for portraiture. Modifications to the sensitization process coupled with the improvement of photographic lenses soon reduced the exposure time to less than a minute. Although daguerreotypes are unique images, they could be copied by re-daguerreotyping the original. Copies were also produced by lithography or engraving. Portraits based upon daguerreotypes appeared in popular periodicals and in books.