How can I tell if something is in the Public Domain?
IMSLP says that both the Strauss Horn concerto #1 and the Mozart horn concerto #2 (K. 417) are NOT in the public domain. What? Isn't it life + 50? They are both, of course, long dead.
This is a question in my new job as orchestra librarian, BTW. Hope it's OK.
There are lots of editions of public domain works that have been edited to include fingerings, bowings, dynamic marks, etc. These editions are often not public domain because they are published under the editor's name. Anything by Mozart is public domain. If not, then it's the particular edition that's copyrighted.
Did finally find the Mozart in PD, but not all the parts.
In the U.S. the Copyright has been extended another generation to about 80 (?) years. Some call it the Disney/Mickey Mouse rule.
US copyright law is more complicated than that, and depends on the year of creation. It's easy to look up if you're interested. It keeps getting extended, and my understanding is that one of the most important forces prompting lawmakers to extend it is lobbying by the corporation that owns copyrights on George Gershwin's legacy. Whenever those copyrights are about to expire they push hard for another extension, and always seem to get it.
The quick answer to the OP's query is if it's in the IMSLP catalog then the chances are that that version (which may well be an original edition) is not in copyright. But always read through the headings carefully because sometimes there are exceptions such as, not in copyright in Canada but is in copyright in the US. Some modern composers may waive copyright in selected instances, so look out for those.
The parts for both of those horn concertos are available to my computer on IMSLP. Try ignoring what they say and dig down to the next level.
Andrew--I found them finally, as you say, but they do not have ALL the parts. Just SOME of the parts. At least I got the second violin parts LOL. Anyway, we ended up just renting the Strauss and will figure out the Mozart when the conductor gets back from a trip. :-)
Make sure the editions match. Articulations could be different, rehearsal numbers different at a minimum. There could even be pitch differences/rhymic differences between the 2nd vln and everything else. Mixing editions is always problematic.