Anime-Beta TNG

I'm a little confused about settei. I know they're copies, but what's stopping sellers from making copies of them and selling those? Are they printed on a certain type of paper or have any other distinctive characteristics?

Original hand-drawn settei do exist. Its just that they are very rare and can be kind of pricey. They are hard to fake since they are usually drawn on studio paper which is usually marked with the sudio's letterhead or logo somewhere. They are also drawn by someone pretty high ranking artists on the team, often the top guy.

After the hand drawn settei are made they are copied by the studio to pass out as reference material for the rest of the art team. It can be pretty hard to distinguish studio-copied settei and settei that are copied by someone just to sell for money. Some people will use notes and other markings on the settei to try to tell if they are real. Still, all of that can be faked. Since the copied settei (also storyboards) are so easy to fake, they do not command the same prices as original settei or other types of pencils.

I am far from an expert but I discuss this a little bit on my web page at http://itamejihada.net/terminology/artwork.html