Exceptions to copyright include (note that these exceptions link back to the specific pages describing them in detail):
Section 108 of the Copyright Act allows for one copy of a copyrighted work to be made for a patron request and for an inter-library loan (for "no more than one article or other contribution to a copyrighted collection or periodical issue, or to a copy of a phonorecord of a small part of any other copyrighted work . . .."
Up to three copies of a work may be made for archival purposes but only when certain detailed circumstances are present (see Section 108(b) & (c), which differ depending on whether the work is a published or unpublished work.
Note that Section 108 exceptions do not apply to pictorial, graphic or sculptural work, or a motion picture or other audiovisual work other than an audiovisual work dealing with news . . ..
A final and important provision of Section 108 provides that the there is NO LIABILITY for a library for "copyright infringement for the unsupervised use of reproducing equipment located on its premises" as long as the copying equipment "displays a notice that the making of a copy may be subject to the copyright law . . .."
Q: If there's no specific exception, such as face-to-face teaching, do I have to first ask permission from the copyright owner before I use a particular item?
A: Not necessarily! Remember to consider fair use, which is a more global exception, before determining that you must ask for permission from the copyright owner.
Q: How does licensing play a role in considering whether I can use a particular item?
A: Even if you might otherwise have a specific right to use an item, for instance, a face-to-face teaching exception to show a legal copy of a movie in class, licensing may prevent you from showing a movie from a particular source. Let's take Netflix for example. When you set up an account with Netflix, you agree (in a click through license) to use it only for "personal use." Thus, many experts agree that you generally cannot show a Netflix show in class because you would be violating the license and you can always contract away your rights through licensing.