In the 1930s and 40s, photographer George Platt Lynes was one of the first people to become known for his commercial and editorial work with celebrities. His photos of the famous made him famous, too. But at the same time, his more private work involved a celebration of the male nude, and that work was not only erotic, taboo-breaking, and illegal to show in public, but aesthetically forward, very much ahead of its time. Now, in the documentary “Hidden Master: The Legacy of George Platt Lynes,” filmmaker Sam Shahid — who previously worked as an art director on the Bruce Weber documentaries “Let’s Get Lost” and “Broken Noses” — showcases this rich body of work from a pioneering gay artist, while also exploring the photographer’s connections to Gertrude Stein, Alfred Kinsey, and others. This vital historical work is currently moving around film festivals, so be on the lookout for it to screen or stream near you.