We approached Black Angel (1946) expecting the usual B-movie noir. There are so many movies like this that we'd never heard of, many of them better than you'd expect. This turned out to be as good as we'd hoped, but not really a B-movie.
It starts with Dan Duryea looking at an apartment building. The camera pans up the face of the building and through the window in a fluid shot that might have made Orson Welles go "hmm". The apartment belongs to Constance Dowling, apparently Duryea's wife. But she tells the doorman not to let him in. The doorman does let in Peter Lorre.
When Constance turns up dead, Duryea isn't under suspicion. He was drinking all night, and then passed out and locked into his dive apartment. John Philips takes the fall, because she was blackmailing him. His wife, June Vincent, can't believe he did it and sets out to prove his innocence, and eventually forms an alliance with Duryea.
Her sweetness and innocence inspires him to stop drinking. His songwriting and piano playing convince her to form a nightclub act with him. They stake out Peter Lorre's club to see if they can find the mysterious McGuffin.
This is all basic noir, down to the Cornell Wilde story it's based on. But it isn't a B, at least it doesn't look like it. The night club, for instance, has a full set of customers, real sets, a band and so forth. Production values, in other words.
I'm not sure the story is quite up to it, in the end. My main problem -SPOILERish - is that Duryea and Vincent spend months singing in a nightclub, clearly getting nowhere, while hubby is sitting on death row. I mean, I guess that was kind of the point - they were falling in love while theoretically she was trying to clear her husband of the murder of his wife. But it didn't work for me, unless I didn't think about it.
So I'd say A for production values, B for tight plot, and full marks for noir.