Open a box of family photographs and all types of pictures spill out: paper prints, cased images, tintypes, Polaroids, snapshots. Knowing when each type of photo was produced is one of the first steps in estimating when a picture was taken—a huge clue to who’s in those mystery pictures. A photo’s format also dictates the best ways to save it for posterity. Gather genealogy clues and preserve your family’s past by following our guide to historical photo formats.

 

Characteristics: A daguerreotype is a copper plate coated with highly polished silver; chemicals including mercury vapor were used to develop the image. Early cameras produced reversed images, but later improvements created true pictures. In order to add realism to the black-and-white image, photo studios employed artists to add color, such as gold jewelry and pink cheeks and lips.