Proof of Public Domain PD Info P ublic D omain M usic A reference site to help identify public domain songs and public domain music . . . You should use a public domain composition only if you have proof of public domain from a legitimate source. If you do not have a legitimate source in your possession, there is no way you can be certain that the music you use is in the public domain. A legitimate source is a tangible copy of the work with a copyright date old enough to be in the public domain .
Sources are almost always either an original or a copy of a book or sheet music.
If you do not do your own research and obtain a legitimate public domain copy of each work you use, you can easily make errors which could result in your having to pay substantial royalties. For sheet music , the copyright date is usually shown on the first page of the music notation. If you are obtaining copies of original sheet music as proof of PD, you should get a photocopy of the cover page as well as the actual pages of music notation. While getting a copy of the cover page may not be absolutely necessary, you may not be able to show whether the copy was made from sheet music or from a book of music without a copy of the cover page. It is always best to be able to absolutely identify your PD source.