Fair use is a doctrine allowing the use or reproduction of copyrighted works without permission from the author, as long as certain conditions are met.
Using copyrighted work in a transformative way, such as altering it significantly or using it for a different purpose, is a large factor in fair use.
The most common cases of fair use are criticism, commentary, and parody. This also applies in education, research, and reporting. However, using a copyrighted work for an educational purpose does not automatically make it fair use.
Fair Use Checklist (Columbia University)
Fair Use Evaluator (American Library Association)
The following four factors are very important in determining fair use:
Orphan works are resources of any format that do not have a clear copyright statement. It is up to you to determine if anyone or any corporation or association owns the rights. The Society of American Archivists offers some directions on how to do this in this document: https://www2.archivists.org/groups/intellectual-property-working-group/orphan-works-statement-of-best-practices