If you browse auction sites and art dealers, you will find an awful lot of phony cartoonist drawings. In fact, here's a new "rule" that I just made up: You should spot many phony drawings. If you prowl eBay and don't see some, it probably means you aren't able to tell real drawings from fake ones and should treat your own judgments accordingly.
The two most often-forged cartoonists seem to me to be Charles Schulz and Jack Kirby. There are always some fake drawings around by these two — sketches someone did and signed their names to — but lately, there seems to be a special epidemic of them. Some of these are accompanied by impressive-looking Certificates of Authenticity or letters from folks claiming lofty credentials to know what's real and what's not.
(I've never quite understood the premise behind Certificates of Authenticity. They seem to be based the assumption that it's possible to forge a piece of art by a great artist but impossible to forge a one-page Xeroxed page by an "authority" you probably never heard of.)
There are good art forgeries and there are bad art forgeries and I am amazed at how bad some of the bad ones are. I just saw where someone paid over $2000 for a quick sketch of Snoopy which the seller swore was by Schulz. If Mr. Schulz did that, he did it with his left foot while coyotes were gnawing on his drawing hand.
Many of the Kirby fakes work like this: An artist — we'll call him Huckleberry Frelinghuysen — traces an existing drawing by Jack and inks his tracing. He signs it "Kirby/Frelinghuysen" and sells it. He may represent it honestly as a tracing or he may lead the buyer to believe that it was an original pencil drawing by Mr. Kirby which he [Mr. Frelinghuysen] obtained and inked on the same piece of paper. If the latter, a later owner is likely to represent it as an actual Kirby drawing inked by Frelinghuysen and price it like an actual Kirby drawing, which it is not. Frelinghuysen may be a talented man but he does not have the power to create an original Jack Kirby drawing.
And I guess I should add a word here about Kirby tracings that are inked and sold by artists who at some point in their careers actually worked with Jack and did at times ink real Kirby pencil art. Most of these guys, like Joe Sinnott and Mike Royer, are careful to label any Kirby re-creation or tracing they do in a way that makes clear the provenance of the piece. At least one artist who inked Kirby's work has not had that kind of integrity. The buyer thinks (wrongly) the piece originated on Kirby's drawing board and pays accordingly.
The forgery market is not, of course, limited to bogus Schulz and Kirby sketches. Right now on eBay, I see counterfeit Ditko, Romita, Steranko, Bruce Timm, Frazetta, Frank Miller and many others. Sometimes, a seller has one or two fakes among dozens of real drawings, which leads me to believe the seller doesn't know — and doesn't know the difference. Some dealers though have enough fakes that one suspects they know darn well they're selling forgeries. Auction sites rarely police this stuff, even in some cases when the legal reps of the artist whose work is forged — or even the artist himself — contacts them.
So watch out. As Abraham Lincoln said, "If an offer seems too good to be true, it's probably false." You might not know Lincoln said that but I have an original letter of his in which he said that and the guy who sold it to me assured me it was genuine. He even showed me that the zip code on the letter was Abe's actual zip code. If that isn't proof, what is?