Per Stanford University, "the term 'public domain' refers to creative materials that are not protected by intellectual property laws such as copyright, trademark, or patent laws. The public owns these works, not an individual author or artist. Anyone can use a public domain work without obtaining permission, but no one can ever own it.
There are four common ways that works arrive in the public domain:
There are a lot of very specific rules and regulations regarding what becomes public domain and when, so determining what is or isn't in the public domain can be a complicated and lengthy process.
Any work that falls into the following categories is in the public domain:
An easy way to remember what’s in the public domain is FRIDGE:
Use this tool to determine if a work is protected by copyright or if it is in the public domain. Move the red arrow on the right up and down based on the parameters of the work and find the answer in the white box in the top right corner.