Copyright
Copyright is federal legal protection for the rights of authors in their works for a limited time period. Copyright law is federal law enacted under the authority of the Copyright Clause in the Constitution, "to promote the Progress of Science and useful Arts, by securing for a limited Time to Authors and Inventors the exclusive Right to their respective Writings and Discoveries."
Under Section 105 of the copyright law, "Copyright protection under this title is not available for any work of the United States Government, but the United States Government is not precluded from receiving and holding copyrights transferred to it by assignment, bequest, or otherwise."
Generally anything published in the United States before 1923 no longer has copyright protection and is in the public domain [1], though works first published in other countries before that time may still be under US copyright. Also, photographs of paintings in the public domain would ordinarily not qualify for copyright protection either.[2]
For Conservapedia's copyright policy, see Conservapedia:Copyright.