This paper presents the story of a long journey to authentication for an untitled painting, claimed to be by Jackson Pollock’s hand. The painting known as Untitled, Red, Black and Silver (RBS) is an abstract expressionist oil-on-canvas board painting, said to have been created in the summer of 1956, weeks before Pollock was killed in a tragic automobile accident. RBS has been the subject of a long-standing disagreement between the artist's girlfriend, Ruth Felicity Kligman, and his estranged wife, Lee Krasner. Ms. Kligman claims that she saw Pollock painting RBS in the summer of 1956 on her used canvas board and that when Pollock completed the work, he gave the painting to her. Mrs. Pollock asserted that the painting was a fake. Lee Krasner died on June 19, 1984. In the early 1990s, Ruth Kligman presented RBS to the newly created 2nd Pollock-Krasner Authentication Committee. At that time, the committee offered to place RBS into Pollock’s Supplement Catalogue Raisonné, published in 1995, in a section listing works needing more study. Kligman rejected the offer. After Ms. Kligman died in 2010, her estate trustees requested a full forensic assessment of RBS, which is presented in this paper.