In the United States, before the Copyright Act of 1976 (which became effective January 1, 1978) was passed, those who published their writings and drawings and photographs were still acting under the rules of the previous Act, the Copyright Act of 1909. Since 1978, copyright is assumed to exist from the moment of creation - the moment the thoughts in your mind become materialized in the physical word. On paper. Whatever. This without the requirement of registration or publication, though you might be wise to still do one or the other.
Under the old Act of 1909, the author was given a copyright for a period of 28 years. Back then, one usually registered their work with the government to establish the date of copyright, but the act of publishing the work could also be used as to establish the date of copyright. Thus, under the 1909 Copyright Act, the date when the 28 years started was either the date of registration of the work, or the date of first publication, whichever was earlier.
Under the 1909 Act, the copyright could be extended, if desired, for a second 28-year term. This extension was by formal application, which had to be made sometime during the 28th year of the initial copyright period. Following the first 28-year period, if the copyright wasn't renewed, or following the second 28-year period, if the copyright WAS renewed, the material then fell into the public domain. Some entities, such as the U.S. Government, were not eligible to obtain copyright (and still aren't) but the above information is what normal authors, artists, and photographers (and songwriters, etc.) were covered under.
This blogger has no argument with the 1909 law, as 56 years of protection are plenty if the author is serious about making an effort to reap the benefits of his work. This blogger, despite being the creator of some intellectual property, is NOT in agreement with the current copyright law in the United States (and most of the rest of the world) because I believe current copyright terms of "life plus 70 years" (or even longer in some cases - up to well over 100 years) defeats the second purpose of copyright in our constitution. That is, copyright and patents were to be authorized by the government in order to encourage arts and invention by giving the creator a monopoly on their sale for a LIMITED amount of time.
The current excessive limits make a mockery of that intention. It also defeats, as I say, the second intention, which was to encourage further innovation and invention and art by others, after that REASONABLE time had expired. Placing the work into the public domain so others could feed off it and use it to make ever better things of their own, was the original intention. Today, invention is largely stagnated in the U.S., I assert, and largely because we are no longer allowed to build upon the inventions and techniques and information of the past after a reasonable waiting period gift to the original creator. Big drug companies with on-staff legal departments seem to be able to live with the law the way it is, but not the common folk.
The perhaps well-intentioned, though shortsighted and misguided, efforts of the late Congressman Sonny Bono (D-CA) in successfully getting amendments passed to the 1976 Copyright Act, has made a tangled jungle out of a copyright system that should be straightforward and crystal clear. In my opinion, it has gone a long way to stifle American innovation and art due to creating what is, in effect, a permanent monopoly. After "life plus 70 years" who the hell cares? The work is no longer timely or even useful for other people to build upon it.
For what it's worth (and it isn't really worth too much) the U.S. Copyright Office says:
"Applying these standards [of the 1909 Act], all works published in the United States before January 1, 1923 are in the public domain." Woop-de-do.
At any rate, don't let predators claiming copyright on materials before that date intimidate you from freely using the materials they bald-facedly and illegally assert copyright over. Go ahead and publish those beautiful Grimms Fairy Tales illustrations to your heart's content (if they are in books published before 1923), and charge money for them if you wish. Just don't claim copyright on them.
And if you get contacted by a museum or some alleged representative of the "Copyright Holder", tell them to get the best lawyer they can find and come ahead on. These people are predators. Taking pictures of old photos and paintings is settled law: it is not original enough to let them copyright their copies. [Bridgeman Art Library v. Corel Corp., 1999.]
The income from derivative works must be shared with the copyright holder. Parts of copyrighted works cannot be used in your derivative work without permission from the copyright holder of that original work. If it has fallen into the public domain, the the original creator no longer has to be consulted.
1. I am not a lawyer
2. I am not YOUR lawyer
3. I advise you to read the copyright law and test cases thereto