Instructions
Reputable galleries or art brokers should offer a certificate of authenticity, a printed document stating the autograph is in fact real.
Try to attend an opening reception or gallery talk featuring the artist you want to collect. That way, you can see the artist sign the print you want to buy and even talk to the artist about his or her work.
Before buying a signed print, inquire about the gallery's return policy so that, if the signature is forged, you can return the piece and get a refund of the purchase price.
Look for the artist's signature online or in reference books to ensure it matches the signature on the print.