Here is some information directly off the U.S. Copyright Office website, the FAQ section. U.S. Copyright law is also in full compliance with all conditions of the international Berne Conventions: How much of someone else's work can I use without getting permission? Under the fair use doctrine of the U.S. copyright statute, it is permissible to use limited portions of a work including quotes, for purposes such as commentary, criticism, news reporting, and scholarly reports. There are no legal rules permitting the use of a specific number of words, a certain number of musical notes, or percentages of a work. Whether a particular use qualifies as fair use depends on all the circumstances. See Circular 21 and FL 102. How much do I have to change in order to claim copyright in someone else's work? Only the owner of copyright in a work has the right to prepare, or to authorize someone else to create a new version of that work. Accordingly, you cannot claim copyright to another's work, no matter how much you change it, unless you have the owner's consent. See Circular 14. As brycetech and I discussed and, I think, agreed in an exchange of IMs, there is much, much more to claiming ownership than making alterations. I always follow the rule that my attorney uses - A derivative work is a derivative work. Only the original copyright owner can authorize a derivative work. Take care and be well. casamerica