How do I check if a Marvel comic is in the public domain?

To determine if a Marvel comic is in the public domain, you need to check the copyright status of the specific comic. Generally, works published before 1928 are in the public domain in the United States. However, copyright terms can be complex and vary depending on the circumstances. Resources like the Stanford Copyright Renewal Database and the U.S. Copyright Office website can help you research the copyright status of individual comics.