www.cartoonbrew.com/law/the-public-domain-is-working-again-no-thanks-to-disney-169658.html

The law protects new works from unauthorized copying while allowing artists free rein on older works.

The Copyright Act of 1909 used to govern copyrights. Under that law, a creator had a copyright on his creation for 28 years from “publication,” which could then be renewed for another 28 years. Thus, after 56 years, a work would enter the public domain.

However, the Congress passed the Copyright Act of 1976, extending copyright protection for works made for hire to 75 years from publication.

Then again, in 1998, Congress passed the Sonny Bono Copyright Term Extension Act (derided as the “Mickey Mouse Protection Act” by some observers due to the Walt Disney Company’s intensive lobbying efforts), which added another twenty years to the term of copyright.

it is because Snow White was in the public domain that it was chosen to be Disney’s first animated feature.
Ironically, much of Disney’s legislative lobbying over the last several decades has been focused on preventing this same opportunity to other artists and filmmakers.

The battle in the coming years will be to prevent further extensions to copyright law that benefit corporations at the expense of creators and society as a whole.