This Q&A was originally published in the Summer 2017 issue of Documentary magazine, a publication of the International Documentary Association, a nonprofit media arts organization based in Los Angeles.

The answer, in a word, is rarely.  And, sad to say, there exists no rule of thumb — like borrowing four bars is ok but five bars isn’t.  Fair use is more complicated.

Fair use is a small hole in the fabric of copyright protection.  Copyright exists for the purpose of benefiting society by encouraging creative people to make new works.  It does that by giving owners of copyright a monopoly in certain rights for a “limited term” (which for current works, endures for the life of the author plus 70 years — not so limited).

Fair use exists because even during the term of copyright, society is benefited by giving teachers, journalists, critics, scientists and others, including filmmakers, the right to use others’ copyrighted works without asking permission and without paying for the privilege.  But given the framework that underlies the purpose of copyright, it shouldn’t come as a great surprise that fair use is a very limited exception.

When it comes to music, that exception is even more limited than usual.  This is because whether or not fair use applies in a given instance depends on four factors that apply to all sorts of borrowings, but are defined in ways that tend to leave out music.

The first factor is the purpose of the use.  Commercial uses are disfavored and so-called “transformative uses” are raised high.  Whether or not a documentary film counts as a “commercial use” is not a settled question, but we know what “transformative” means:  to qualify for fair use, the use has to serve a purpose other than the one that the copyrighted work originally served.

Music usually serves the purpose of triggering an emotion, like happiness or sadness, or of accompanying movement, be it fast or slow, as in dance.  Why does a documentary maker put a piece of music in a film?  Sometimes, as in a film about music, it’s to criticize or comment on a piece, or make fun of it, as in a parody of the music itself.  That’s transformative.  But more often than not, the documentary maker wants the music there to appeal to an emotion or accompany movement.  That’s not transformative and the fair use factor rejects the use.

The second factor depends on the type of the copyrighted work being borrowed.  As a general rule, works of the creative imagination (as opposed to fact-based works) are more difficult to borrow from on a fair use basis.  Musical pieces are works of the creative imagination.

The third factor focuses on how much of the borrowed work is being taken.  The measure isn’t only quantitative (as in how many seconds compared to the length of the musical piece) but also qualitative (as in whether or not the “heart” of the piece is taken).  Songs tend to be short, compared to, say, a novel or a feature-length film.  A relatively large portion of a musical piece can be comprised by a relatively short taking.  Also, the “heart” of a musical piece — the part with the greatest effect — is often the part of greatest interest to a filmmaker.  The odds for fair use treatment are not good.

The fourth factor asks whether the particular kind of borrowing, if it became widespread, would undermine the economic value of the work for the copyright owner.  If there’s a structure in place for licensing the right that’s proposed to be exercised on a fair use basis, that counts against fair use.  The owners of copyrights in music — generally music publishers—and their agents, like the Harry Fox Agency, make it their business to furnish licenses for a price.  The structure is there.

And not only is the licensing structure in place, so is the structure for policing infringements.  Knowing that the fair use deck is stacked against use of music, publishers tend to enforce their rights.  Both legally and practically, fair use of music in a film for any purpose other than criticism or parody, is usually not a good bet.