Photo manipulation has been used to deceive or persuade viewers or improve storytelling and self-expression. Often, even subtle and discreet changes can have a profound impact on how a photograph is interpreted or judged. As early as the American Civil War, photographs were published as engravings based on more than one negative. In 1860, a photograph of the politician John Calhoun was manipulated and his body was used in another photograph with the head of the president of the United States, Abraham Lincoln. This photo credits itself as the first manipulated photo.