Eyes stare out at you from an old black-and-white photo. But are they the eyes of Great-grandma or Great-great-grandma? Or maybe the woman is your great-aunt Frederica. If only you could ask her.

 

Well, you can—in a way. Clues to when the picture was taken are right there in front of you. And once you know when that picture was taken, you could check your family tree and see which female relatives were alive and about her age at the time. What clues, you ask? The photo’s format—daguerreotype, tintype, paper print and so on—for starters.