Yesterday was Public Domain Day 2014, marking the passage of creative works into the public sphere. We may be a day late in letting you know, but those works will be public forever! The laws vary by country/region, so not everything they are celebrating is now in the public domain in the United States.
From the Public Domain Day site: >>Every year on New Year’s Day, in fact, due to the expiration of copyright protection terms on works produced by authors who died several decades earlier, thousands of works enter the public domain – that is, their content is no longer owned or controlled by anyone, but it rather becomes a common treasure, available for anyone to freely use for any purpose.<<
-The Public Domain Review has a Guide to Finding Interesting Public Domain Works Online
-The American Library Association offers a handy dandy interactive tool for estimating if a particular work in the public domain or not: Is it Protected by Copyright?
-Public Domain Sherpa has their own copyright calculator which lets you get in a few more details.
-Cornell has a massive chart: Copyright Term and the Public Domain in the United States
–Google’s Advanced Image Search form lets you determine the type of image by license you need.
To dig deeper in the stacks:
Public domain : how to find & use copyright-free writings, music, art & more / by Stephen Fishman. – KF3022.Z9 F57 2006
Common as air : revolution, art, and ownership / Lewis Hyde. – ZA3270 .H93 2010
Public domain : enclosing the commons of the mind / James Boyle.- K1401 .B689 2008
Free culture : the nature and future of creativity / Lawrence Lessig. – KF2979 .L47 2005
Permissions, a survival guide : blunt talk about art as intellectual property / Susan M. Bielstein. – KF3050 .B54 2006