In the intellectual property world, 2019 is a special year. For the first time in 20 years, copyrighted works have resumed entering the public domain en masse due to the expiration of their copyright term. This means as of January 1, all works originally published in 1923 are now in the public domain.
Works stopped entering the public domain in 1998 due to the passage of a law that year which extended the copyright term of works created before 1978 by an additional 20 years. So, works that would have entered the public domain in 1999 remained under copyright protection until this year.
Here’s a brief copyright history lesson. Under the United States Copyright Act of 1909, copyrighted works were entitled to an initial 28-year term from the date of publication and a second renewal term of an additional 28 years. So, in total, a work could be protected by copyright for up to 56 years. However, a work would enter the public domain if it lacked a proper copyright notice, e.g., © Dirk Vanover 2019, or if it wasn’t renewed.
The 1976 Copyright Act changed the duration of copyright terms for works created before 1978 (the year the Act went into effect) to 75 years from the date of publication, more or less. In 1998, the Copyright Term Extension Act, aka the Sonny Bono Act, aka the Mickey Mouse Act, changed the length of copyright terms again by adding an additional 20 years to the term—95 years from the date of publication.
Works created by a single author and protected by the 1909 Act enter the public domain piecemeal—as their copyright terms expire. This is why works created in 1923 are now in the public domain after 95 years. However, works created by a single author after 1978 are protected for the life of the author plus 70 years and enter the public domain all at once.
I’m bringing this up for two reasons. First, it’s great that works are entering the public domain again. Even though works published in 1923 or after may have already entered the public domain, it can be difficult to determine. As mentioned above, there are only two other ways for a work to have entered the public domain previously – either the work lacked or had an improper copyright notice, or it wasn’t renewed after its initial 28-year term. To be certain a work is in the public domain would require research, which can be lengthy, costly, and indeterminate.
Second, I often see people discussing online whether such-and-such golden age superhero is in the public domain. As might be evident from what I’ve written above, determining this can be tricky. If the work was created in 1923 or earlier, which really isn’t applicable because not many superheroes existed back then, now it is in the public domain—at least those original aspects introduced in that work. For any other work, it is safest to assume it is protected by copyright. Otherwise, you’ll have to determine if the work fell into the public domain due to a lack of copyright notice or if it wasn’t renewed. Furthermore, even if a work has entered the public domain, only that specific work itself is in the public domain. So, if you want to utilize the character in a new work, you’d be limited to just those elements of the character introduced in the work that is in the public domain. (See my post about Sherlock Holmes here for a further explanation).Overall, it is good news for everyone that previously copyrighted works are now entering the public domain again. However, if you want to use a character you believe to be in the public domain, you should proceed with caution and make sure you’re in the clear before you create a new work. Otherwise, you could expose yourself to a possible copyright infringement lawsuit.
 However, corporate works and works made for hire are still a fixed term of 95 years from publication or 120 years from creation, whichever is shorter.