Public Domain is also the title of a book written by Attorney Stephen Fishman
, and published by Nolo Press
. This book uses "public domain" to mean "copyright free" which is how I will use it also. I will also limit myself to works originally published in the USA
. In general the USA respects the copyright law
of the country of publication, but that's a whole other kettle of fish.
I will freely use his facts and ideas, because facts and ideas are not covered by copyright.
Everything first published before January 1, 1923 is in the public domain.
Almost everything published before January 1, 1964 is in the public domain. The only publications in this category still under copyright are those for which a copyright form was filled out and submitted, AND a copyright extension form was filled out and submitted 28 years later. It is estimated that roughly 85% of all works published between 1923 and 1963 are in the public domain. The percentage varies greatly by the type of work.
The records of copyright extension forms are in bad shape. It is nearly impossible to tell, for certain, if a particular book from this period is still under copyright.
Here is a table for things registered with the Copyright Office in 1931-32 and not renewed in 1958-59. Note that there are many many things created and published in 1931-32 that were never registered and never had any copyright protection.
I am copying this table from the book Public Domain, which itself is copyrighted. I can use it, though, through either of two loopholes. The first is Fair Use. I'm using only a very small excerpt and stating my source. The second is that Mr. Fishman got this data from the Copyright Office, and therefore was produced by the Federal Government, and therefore was already in the public domain when he used it.
Type of Work Allowed to Expire
sermons and other works
for oral delivery 99.6%
Works of Art 96%
Technical Drawings 99.6%
Art Prints 96%
Let me re-iterate that these numbers do not
reflect the fraction of things
registered with the Copyright Office in the first place. Thus the percentage
of things produced in 1931-32 that are now
in the public domain is rather closer to 100%