Untied, Riggs was diagnosed with HIV after undergoing treatment for near-fatal kidney failure at a hospital in Germany. Despite his deteriorating health, Riggs decided to continue to teach at Berkeley and make documentaries. In the short 1990 piece Affirmations, Riggs explored the African-American males' sexuality and relationship with the African-American community at large. Some of the men expressed the lack of acceptance within the African-American community and the divide their sexual orientation caused. In 1991, Riggs directed and produced Anthem, a short documentary about African-American male sexuality. In 1991, Marlon founded Signifyin' Works, a non-profit production company that produces films about African-American history and culture. The 1992 documentary Color Adjustment was Riggs's second film to air on the PBS television series P.O.V., focusing on the representation of African Americans in primetime television from "Amos 'n' Andy" to "The Cosby Show." The film was produced with Vivian Kleiman, edited by Debbie Hoffmann, and narrated by actress Ruby Dee. It includes an original music score by Mary Watkins. In 1992, Riggs directed the film Non, Je Ne Regrette Rien (No Regret), in which five black gay men who are HIV-positive discuss how they are battling the double stigmas surrounding their infection and homosexuality. The series was screened on World AIDS Day and Day Without Art. It included the participation of Phil Zwickler, David Wojnarowicz, Ellen Spiro, Vivian Kleiman, and others. In 1993, Riggs received an honorary doctorate from the California College of Arts and Crafts. The same year, Riggs's experimental short Anthem was featured in Frameline's collection of short films entitled Boys' Shorts: The New Queer Cinema. Shortly after completing Color Adjustment, Riggs began work on what was to be his final film Black Is...Black Ain't, but he died at the age of 37 from complications caused by AIDS on April 5, 1994, before he could complete it. The project was completed posthumously by co-producer Nicole Atkinson, co-director/editor Christiane Badgley, under the supervision of the board of directors of Signifyin' Works: Herman Gray, Vivian Kleiman, and Patricia Turner. Riggs also wrote poetry, and Tongues Untied contains several of his poems about his life experiences as a black gay man. Writings Riggs's writings were published during the late 1980s and early 1990s in various art and literary journals such as Black American Literature Forum, Art Journal, and High Performance as well as anthologies such as Brother to Brother: Collected Writings by Black Gay