I am something of a "photography genealogist" for the family. My father's half-aunt lived to be 103, never had children, and left behind a suitcase stuffed with photos — going back to a tintype of her mother from the 1880's. I was lucky the suitcase was eventually handed over to me.
That started my obsession with collecting all the family photos I could find. And starting with that suitcase, I scanned every photo and embarked on cleaning up and adjusting levels (etc.) for every interesting photo in the lot.
Sometimes a few lines of text on the back or border gave me the date or subject of the photo. Often there was nothing though. Nonetheless, I was slowly able to recognize people in the photos, associate a name to them (from also doing traditional genealogy with Ancestry.com). Stories emerged in some cases (my great grandmother's big road-trip vacation in 1925 after the divorce from her unfaithful husband, the mysterious young woman in the Denver photos that I was eventually able to trace to a teen daughter who died in Mexico, Missouri while away at music school, etc.)
And as I was able to figure out the photos, order them, I got to also see the progress of photography and cameras. The tintype and early collodion photos were all in a studio setting (perhaps a single photography studio in Kansas City in 1880? She was only a young girl, her father a farmer — he must have been putting on airs to have a studio photograph taken of his young daughter).
And then the Kodak Brownie (I assume) makes the scene by 1920 or so for the family and photos start to appear taken in the field, on the farm — no longer in studios. The quality though suffers immensely.
Better Kodaks (or similar) come into the family by the 30's and candid, amatuer photography now rivals the quality of the earlier studio photos. Somewhat.
Suddenly in the 1950's square color photos appear in the collection and the quality is actually some of the worst of all the family photos. So sad that we traded fast lenses and film for color. I am not sure the quality ever quite caught up again to the better B&W until we get to modern digital.