The National Board of Review (NBR) had been established by members of the film industry in 1909 in an attempt to preempt state and local censorship of films. As a result of Munson's first film, Inspiration (1915), the NBR in February 1916 revised its policy on depictions of nudity to require a critical review to pass films only when it "an essential element of a drama the nature of which warrants such presentation." Purity was submitted to the NBR in July 1916 and it held two screenings before a select group of invitees and obtained their disparate views of the film. As a result, the NBR neither passed nor rejected the film, instead issuing a list of 10 recommended deletions with a note that local censors should consider their community standards and public opinion. The deletions included scenes in the prologue where the neckline of Munson's gown was too low, scenes with suggestive expressions on the faces of men, a word on an intertitle, a shot of a nude painting in the artist's studio, all shots of Munson changing clothes at the stream and in the studio, all shots of Munson posing as reproductions of masterpieces at the party, and any shot of Munson moving while nude, while scenes of Munson posing nude at the studio should be reduced to one or two short flashes.
