Copyright is an inherently contradictory legal issue. It is at the same time highly restrictive and very narrow. It is highly restrictive due to the broad nature of the current coverage applying automatically to any "work." This automatic coverage rule applied by the Berne Convention, extends to all 165 participating countries. Even though current coverage is broad the actual application of copyright is very narrow by reason of the fact that copyright protection is based on specific statutory provisions. Failure to comply with the statutes' provisions, a lapse in time or application can negate copyright protection. In other words, some rights, such as civil rights, apply to everyone in a particular jurisdiction and are lost only by some affirmative act, such as committing a felony. Copyright is not universally applied but is subject to specific statutory requirements.
The application of copyright law has changed significantly over the past 200 years or so, from very limited protection for very specific types of works, to the much more expansive scheme prevalent today throughout the world. Once a work is no longer protected by copyright anywhere in the world, there are virtually no provisions allowing for the work to become re-subject to copyright claims. It is this issue of copyright claims that is most misunderstood of all of the many misunderstandings about this area of the law.
Copyright protection can be lost through failure to assert a copyright claim. If I publish a photograph online and it is copied multiple times and I make no effort to protect my right to claim copyright protection, then, at some point, I may lose that protection as the photograph "passes into the public domain." Even though this is the case, this process is far from simple or uncontroversial. I may make a claim even if many thousands (millions) of copies have been made but the issue of whether or not that claim will be enforced against any one or more of the violations is problematic. Nothing stops me from making a claim of violation except failure to follow the procedural prerequisites of jurisdiction in the courts. But there are a multitude of practical reasons why trying to enforce a claim my not succeed.
Now, what about the other side of the issue? What about those who assert some kind of "ownership" to works (usually some kind of document or photograph) that is clearly outside of the statutory copyright protection. For example, what about repositories and libraries that limit access to certain documents that can not, by their age and nature, be protected under any extension of the copyright law? The first issue is obvious. Who owns the copyright? The repository or library, simply by virtue of its possession of a copy of the document or photograph, has NO copyright interest whatsoever. Period. No possible issues here at all. So any restrictions placed on access to old documents that are out of any possible copyright claim, cannot possibly be based on a concern about someone making a claim under that non-existent copyright. I will refer to documents that are no longer covered by any arguable copyright protection as in the "public domain."
If I obtain a copy of a pubic domain document, first, there is no way that I can re-impose copyright protection (there are presently some exceptions to this rule if the work is still protected by one of the Berne Treaty participants. But I am referring to documents that have no ongoing protection at all anywhere). Secondly, since the document has no copyright protection, there is nothing a repository or library can do to prevent me from making a complete copy of the work, other than physically restraining me from doing so.
By what right do repositories (including governments) and libraries claim ownership and control of their collections? It is simple. If I own a book, I do not have to let you see it or use it. This has nothing whatsoever to do with copyright, since I do not own the copyright to the book, but it has to do with property and ownership. Can I own an copyrighted book? Of course, the answer is yes. Therefore, if I have copy and you want to use it, I can impose whatever restrictions I want on the use of the book. The real question here is how enforceable is that control? What if I walk into your library and without your knowledge or your permission, completely copy a book in the public domain? What can you do to me? You have no rights to the book other than your ownership rights. Those rights do not extend to any sort-of copyright (see the word "copy") protection. Basically, you can prevent me from having any further entry into your repository or library. That's it.
Any rights to a copy in violation of a copyright claim lie with the owner of the copyright not the owner of a copy of the copyrighted work. If I own a work, but not the copyright, can I charge you a pay-per-view. Think movie theaters. Yes, you can.
This is a practical problem. You want access to the library. The library has the book you want. You have to play by the rules of the library to get access to the book. As long as you do not damage any of the library's materials, your copy is your copy. But you might (and probably will) lose access to the collection. Any claims made in excess of the basic laws of contract and copyright are essentially unenforceable outside of the confines of the institution making the claim. Could you be sued? Hmm. Yes, anyone with the money to file a lawsuit can do so. Will they win? Depends on the facts.