Trial Proof prints are unique color combinations that are not part of the regular edition print portfolio. Andy Warhol tried many different color combinations of each print to decide the color combination he wanted to use for the regular edition.
Beginning in 1980 with "Jews of the Twentieth Century", the unused color combination prints were signed and numbered "TP" before the edition number, put into portfolios and sold. Since Trial proofs are unique prints, they typically fetch a price premium over the regular edition prints. The barometer of price is the beauty of the color combination.
Better-known Andy Warhol Portfolios with Trial Proof editions:
Jews of the Twentieth Century (25), Myths (30), Endangered Species (30), Details of Renaissance paintings (36), Reigning Queens (30), Ads (30), Cowboys and Indians (36), Hans Christian Andersen (36), Moonwalk (66), and Camouflage (84 - not in portfolios).
Auction Houses often include Trial Proof prints into the Paintings sales, not the Print sales as Trial Proofs are unique paintings on paper.
