Just got back from a showing at The Thin Man at the theater. I love watching Myrna Loy in that movie: the classy styles, the cute faces, the witty banter. She and William Powell have a great dynamic and on screen chemistry, I guess that's why they made like 5 sequels. It's weird, no matter how many times I see that movie, while I can remember the big twist climax, I can never actually remember the identity of the murderer. It's like that solution is almost an after thought. Nothing in the plot can really lead you to the conclusion, and even Nick, the detective, seems to only get to it at the same moment the movie shows it to us.
I was struck by some of noirish shadows, but mostly the film eschews the noir look. One scene that does take place mostly in the dark, as Nick uses a flashlight to investigate a dark room, is shot in a really unengaging way, without the dynamic shadows and dramatic lighting you get in a good noir. Oddly one scene that most looks like that is a non-dramatic scene of Nick and Nora in their hotel room late at night, lit only (primarily) by a lamp in between their beds. Nora is leaning back and the light casts most of her face in shadow. It leads up to a bit of drama but is primarily a scene played for comedy. (I tried to find a screenshot of that scene but failed.)