'The Sign on the Door' is based on a play by Channing Pollock, a prolific playwright who is now utterly forgotten. Pollock's most significant credit isn't listed in IMDb: when the German silent film 'Metropolis' was readied for U.S. distribution, Pollock was given the job of writing English-language intertitles that would simplify the story for American audiences. Pollock chose to chop out large portions of the film, including a crucial subplot about the hero's deceased mother.
The IMDb biography for playwright Channing Pollock states that he was an 'illusionist'. It's hard to believe that there were TWO unrelated men named Channing Pollock, but in fact the playwright and the illusionist are two different people. The illusionist is a resident of England, an incredibly handsome stage magician who performs under the name Channing Pollock.
I've seen the Library of Congress print of 'The Sign on the Door', and I'm sorry I bothered. This movie is somewhere between piffle and tosh. It might be tiffle, but it's surely not posh. SPOILERS THROUGHOUT. Norma Talmadge plays a woman with a dark secret in her past, now happily married to wealthy Lafe Regan. (Until Peter Lawford played Senator Lafe Smith in 'Advise and Consent', this must have been the only movie featuring a rich man named Lafe.) Perennial screen cad Lew Cody, hissable as ever, lures Norma to his room by threatening to reveal her secret. He hangs a do-not-disturb sign on his door. As soon as he's alone with Norma, he tries to have his way with her ... but a stranger rushes in and tries to shoot him. They grapple for the weapon. Cody is shot dead. The police come rolling in, just in time to nick Norma.
Now, see, if Norma would just reveal her Dark Secret, the movie would be over and we could all go home. But then there'd be no movie. So, she has to bite her lip and cringe and tremble for another four or five reels. It's clear that she's Protecting Someone Else, and the only suspense here (what there is of it) is whom. If you must know, it's her daughter. So long as Norma keeps mum, she stands to be hanged for murdering Cody. (Would that make her a Cody pendant?) Herbert Brenon was a good director for stories that had an air of fantasy ('Peter Pan') or unreality ('Laugh Clown Laugh'), but here his technique only emphasises the implausibility of this story. I'll rate this dull 'suspense' film one point out of 10.