[Hankphenom]

This may not be very helpful, but real aging has a certain look to it, fake aging has a certain look to it. If you haven't seen enough of either to know the difference, you probably shouldn't be buying them. The context of availability is another clue, but not always decisive. eBay is full of fakes, but occasionally a real one pops up. In other venues they might usually be real, but occasionally a repro will sneak in. I would never buy anything framed without provenance. I'm as interested, or more, in the back than the front. Fakes are usually uniform on both sides in their "aging," whereas a real old piece will normally have suffered more on one side than the other. And sometimes your other senses are better than your eyes: old paper should smell musty, and it should not feel smooth. Hope this helps some.