Tintypes are a type of photograph made by creating a direct positive on a thin sheet of metal, usually iron. This process was popular in the mid-19th century, particularly during the American Civil War, because it was quick and inexpensive. The images are characterized by their dark, glossy finish and were often used for portraits. The tintype process involves coating the metal with a light-sensitive emulsion, exposing it in a camera, and then developing it with chemicals. Unlike traditional photographs, tintypes do not require a negative, making them unique. They are considered an important part of the history of photography and are often collected by enthusiasts.