When Copyright Protection Becomes Public Domain (means no longer covered by the copyright)
The data below will let you know when you can safely use a piece of art or music without permission because it is now in public domain after copyright protection expiration, or how long the copyright protection will last.
Published before 1923 - now in public domain
Published from 1923 to 1963 - When published with a copyright notice © or "Copyright [dates] by [author/owner]" - copyright protection lasts 28 years and could be renewed for an additional 67 years for a total of 95 years. If not renewed, now in public domain.
Published from 1923 to 1963 - When published with no notice - now in public domain
Published from 1964 to 1977 - When published with notice - copyright protection lasts 28 years for first term; automatic extension of 67 years for second term for a total of 95 years.
Created before 1/1/1978 but not published - copyright notice is irrelevant - copyright protection lasts for the life of author and 70 years or 12/31/2002, whichever is greater
Created before 1/1/1978 and published between 1/1/1978 and 12/31/2002 - notice is irrelevant - copyright protecion lasts the life of author and 70 years or 12/31/2047, whichever is greater
Created 1/1/1978 or after - When work is fixed in tangible medium of expression - notice is irrelevant - copyright protecion lasts for the life of author and 70 years based on the the longest living author if jointly created or if work of corporate authorship, works for hire, or anonymous and pseudonymous works, the shorter of 95 years from publication, or 120 years from creation.
https://www.harryfox.com/public/DoIneedaMechanicalLicense.jsp