The differences between collectible first-edition comic books and valueless reprints can be subtle. Additionally, these differences routinely vary by publisher, brand, series and print date, making it difficult for the novice comic book collector to know when he has the genuine article. Fortunately, there are a number of general methods one can use to identify mass reprints and the poorest of forgeries. Regardless, it is best to seek out specific expert advice before purchasing or selling a potentially rare comic book.
Scan the cover and inside pages for the words "reprint", "reprint edition" or similar. Additionally, look for the indicia information, usually printed on the first or last pages of a comic book. Just like paperback novels, reprinted comic books will list when they were printed originally and to which reprint run they belong. First editions usually have a "#1" or "First Edition" printed on the cover, or in the indicia, if applicable.
Check the age. Valuable comics are typically older, dating from the 1970s or before, and the quality of the printing was often inconsistent. As such, mint-condition comic books from the early to mid-20th century are very rare. Since paper and ink deteriorate over time, a comic book that still looks brand new and claims to be a first edition is probably a reprint or forgery.
Review the advertisements and coupons. If you know a comic book debuted in the 1930s, but contains advertisements for modern products, or if the comic contains ads and coupons without company contact information, it is safe to assume the comic book is a reprint edition.
Do your research. Visit online forums geared toward specific comic book runs, publishers and characters, or visit your local comic book shop to have the owner appraise it. Often there are subtle indications, like a difference in the shape of a price box, the size of the comic book or the omission of innocuous text that will give a forgery away.