Dating photo stock

[steve B]

Yeah, DRCY really knows this stuff.

I'm just someone who's looked through .....I don't even know how many boxes of old photos at shops and flea markets. I have a pretty good feel for the age of something, but it's usually harder to explain.

I will say that the stuff mentioned here about how the paper reacts to a blacklight applies to photo paper very well, but only in a general sense for other papers. Most of the modern acid free papers won't react, and neither will some modern low quality cardstocks. BUT, there are older papers that do react, back into the 1880's and perhaps before (1880's is the oldest I own) They're not exactly common, but they are out there.