Since you have a lot of experience in poster collecting, how prevalent is it that people try to pass off copies as originals?
It's not prevalent....what's more likely is that someone who posseses a poster they believe to be an original unknowingly tries selling it as an original, when in fact it's a repro. I've come across this situation 2 or 3 times in my 25 years of collecting. The seller honestly believed the posters to be original, but close inspection proved otherwise.
I'm much more concerned about repros floating around now than I was back in the early '80's. When I started collecting, Curly 1-sheets were only worth $100-200, not thousands of dollars like today, so there wasn't as much incentive to produce a repro. Also, technology back then wasn't as sophisticated as today...the average person didn't have access to digital imaging, laser printers etc.
Getting back to the paper, in one case I can remember about 15 years ago, the feel of the paper was a tipoff that I had unknowlingly purchased a repro. I bought a "Microphonies" 1-sheet thru the mail and as soon as it arrived I became suspicious because the paper looked unusually white. This isn't proof postitive because sometimes people have posters bleached to clean them up and remove stains. But having seen many many 1-sheets before, the whiteness of this one just raised a red flag. Then I felt the paper. It had an unusual waxy feel to it, unlike any other 1-sheets I had in my collection. Again, not proof positive because during WWII there were tremendous paper shortages and there was some variation in the type of paper used in printing 1-sheets, but this was clearly strike two.
Next I got out a photo of a "Microphonies" 1-sheet that my friend had sent me from his collection. I noticed that behind Larry's hair was a dark curtain as a backdrop. In the photo I could clearly see the line of delineation between Larry's hair and the curtain. But in the poster I had in front of me, the hair and curtain blended together...you couldn't tell where one ended and the other began. So I could actually see more detail in the photo than I could in the poster!! There's no way that a photo of a poster should have more clarity than the poster itself. That was strike three... combining all the info togther I knew this had to be a repro.
I was lucky in that the seller gave me my money back. He was not an experienced poster dealer and I have to say, that the overall quality of the poster was really quite good....something that could have easily fooled someone that didn't have the experience or availability of
a photo that I had. I don't believe he was trying to pull one over on me.
Since then, I've always had a concern over mounted posters....because you can't feel the paper. If I'm going to drop big bucks on a poster I want to be sure it's real, and feeling the paper is just one step an experienced collector uses to gain some assurance about what he's buying.
Gary