The Case of The Partially Public Domain Character

Dear Rich: Help! I'm working on a graphic novel using Dr. Jekyll and Mr. Hyde and Sherlock Holmes. I thought Sherlock Holmes was in the public domain but recently read that some Sherlock Holmes is now in the public domain but some isn't. That made me wonder if Dr. Jekyll and Mr. Hyde were public domain? How do you know for sure which is PD and what isn't? Yes, Jekyll, Hyde and Holmes are in the public domain (although some Holmes is still protected as we'll explain below). Determining public domain status is not exactly elementary, but there is a method of figuring it out based on the year of publication in the U.S.  Basically, any characters that appeared in publications prior to 1923 are PD in the U.S. The Strange Case of Dr. Jekyll and Mr. Hyde was first published in 1886 and has therefore fallen through the public domain trapdoor (along with the characters within the covers). Sir Arthur Conan Doyle's characters appeared in approximately 50 stories published before 1923, and 10 stories afterwards. In the case you mentioned, Doyle's estate argued that the "whole character" was not formed until the final post-1922 work was published. The Seventh Circuit court of Appeals disagreed and held that the Holmes character who appeared before 1923 is PD -- so, you're free to copy him and Watson. But the remaining 10 works are still protected and you cannot use elements from these works -- for example, you can't reference the fact that Watson had a second wife. (Here's a summary of Sherlock's copyright history.)
BTW Dept ... If you're looking for more match-ups between public domain characters check out this site or this one.