This article analyzes Shirley Clarke's seminal film, Portrait of Jason (US, 1967). Through an examination of the film's formal qualities within the context of its production and reception, this article argues that the film is best understood as a “screen test.” The relatively scant pieces of scholarship that do engage with Clarke's career and with Portrait of Jason share a particular line of argumentation: that this work defies categorization. While this makes for a fundamental and significant insight, it produces an overall portrait of privation that does not sufficiently identify the film's critical test of realism — both cinematic and identitarian. This essay argues that failure to achieve recognition under the normative presumptions that underlie our understanding of formations of both nonfiction and race/sexuality is arguably the source of the film's most productive tension. And so the designation of “screen test” engenders an identity for the film that situates its formal indeterminancy as its most critical feature. This analysis of Portrait of Jason necessarily examines the particular intersections of documentary cinema, gender/sexuality, spectatorship, and textual analysis.