Audioslave Concert Poster Toronto 2005 Artist Proof. Artist Proof Concert Poster. 35? X 14.75? VERY LIMITED A/P Edition of ONLY 20. Signed & Numbered by Justin Hampton. What is an Artist’s Proof? An Artist’s Proof is an old tradition of reserving a quantity of prints for the artist’s use, printed at the same time as the regular edition without changes. In the early days of printing, these prints were the only remuneration the poor artist received. At visiblevibrations, we only sell ORIGINAL Concert Posters, Art Prints, Music Memorabilia and Limited Edition Art Toys!