Types of Antique Photographs

Q: What is the difference between daguerreotypes, ambrotypes and tintypes? I have several 19th-century photographs, some on paper and some on metal, and I don’t know what they are or how to care for them.

A: We get a lot of letters about old photographs. Daguerreotypes, introduced in the United States in 1839, got their name from their inventor, the Frenchman Louis Daguerre. They are positive images made directly on a silvered copperplate. Ambrotypes, introduced in the 1850s, were made by a wet-plate process that created a negative image on glass. It’s seen as a positive image when placed against a dark backing. Next came ferrotypes, better known as tintypes, which were positive images on tinned iron. Tintypes were inexpensive and became widely popular during the Civil War. Keep all of your old photos out of sunlight and away from heat and excess moisture. Never touch the image with your fingertips, and don’t use tape or glue to mount them. Store them in archival boxes you can buy at a photography shop, or display them mounted and matted on acid-free museum board and covered with Plexiglas to guard against ultraviolet light.