By which I mean is there a website where I can plug in the names of, say, Doc Savage and see who owns them now? I’m idly curious about some obscure comic properties.
Well, they won’t be copywritten either way. Trademarked, maybe. Just to help you in your search.
No firm answer to your question, but a clarification: the word is copyright, as in “the right to make copies.” The adjective is “copyrighted”.
Now, for a half-answer… It appears that for Doc Savage (Man of Bronze!) the trademark and perhaps the copyright is held by Conde Nast. The comments in this article included references to several sites where you can peruse renewal records and look to see which properties have / have not been renewed. And yes – the stories and works of individual art would be copyrighted. The characters would be trademarked.
Good lord! Are they going to make the Man of Bronze model for VOGUE?!