One of the reasons that Frankenstein’s monster is one of the best-known horror characters is the classic film adaptation of Mary Shelley’s novel directed by James Whale, simply called Frankenstein. Another reason is the fact that the character has been so long in the Public Domain. The film, however, is not.
The characters of Victor Frankenstein and his unnamed monster were created in 1818, and entered the Public Domain in the US by the mid-1800s. This made it a great option for Universal Pictures when they decided to expand on the success of their Dracula movie.
The fact that the film is still under copyright is important, because it effectively reinvented “Frankenstein”. Even though the novel had already been adapted as a stage play, James Whale and makeup artist Jack Pierce invented the look that everyone today associates with the monster, and the movie created elements such as Kenneth Strickfaden’s electrical effects for his “birth” scene. None of these can be used today without permission, despite the fact that the copyright was supposed to expire at the end of 1987. So when Tri-Star adapted the novel as a film in 1994, they had to tread very very carefully to avoid lawsuits from Universal.