I'm really enjoying this conversation
. I'll start with my reply to steingar's message.
I think it's awesome you approve selling folds of your models by others! I REALLY encourage every origami creator to explicitly state what they allow and what they don't regarding their models. I've only started doing that myself.
OK, so let's continue with the discussion. I'm copying here exactly what is copyright protected and what isn't according to the official document of the US copyright law.
102. Subject matter of copyright: In general
(a) Copyright protection subsists, in accordance with this title, in original works of authorship fixed in any tangible medium of expression, now known or later developed, from which they can be perceived, reproduced, or otherwise communicated, either directly or with the aid of a machine or device. Works of authorship include the following categories:
(1) literary works;
(2) musical works, including any accompanying words;
(3) dramatic works, including any accompanying music;
(4) pantomimes and choreographic works;
(5) pictorial, graphic, and sculptural works;
(6) motion pictures and other audiovisual works;
(7) sound recordings; and
(8) architectural works.
(b) In no case does copyright protection for an original work of authorship extend to any idea, procedure, process, system, method of operation, concept, principle, or discovery, regardless of the form in which it is described, explained, illustrated, or embodied in such work.
I highligthed the words. Source:
https://www.copyright.gov/title17/92chap1.html
That's it. That's the whole statement of what is and isn't protected by copyright in the US. What I want to emphasize is that techniques aren't a subject of the US copyright law. Original pictorial, graphic, and sculptural works of authorship are protected by copyright in the US... period. It doesn't matter if the work was painted using watercolors, carved in wood or folded in paper. What does matter is that the work must be original, instead of based on another work, it must also be fixed in a tangible medium, be percibable somehow as well as reproducible. If you insist in that the technique must appear in the copyright law document for its works to be protected, then none of them would be. Techniques aren't part of the document.
Besides that you question what is copyright protected between a picture of a fold of the model, instructions for folding the model, and the original fold of the model. The answer is that they can all be subject of copyright protection; although there are certain details to explain first. Now, since the subject of this discussion is if selling folds of someone else's model is allowed or not, particularly in the US, then only the copyright of the original fold, or folded work if you prefer, is of interest here. Its copyright is what is being infringed by the sale of those other folds of the same model.
You also mention that, if a original folded work was really copyright protected, then it would protect just that specific fold with that size, type of paper, colors, etc. OK, so let me quote now about "derivative works" also from the official document of the US copyright law:
101. Definitions
...A “derivative work” is a work based upon one or more preexisting works, such as a translation, musical arrangement, dramatization, fictionalization, motion picture version, sound recording, art reproduction, abridgment, condensation, or any other form in which a work may be recast, transformed, or adapted. A work consisting of editorial revisions, annotations, elaborations, or other modifications, which, as a whole, represent an original work of authorship, is a “derivative work”...
103. Subject matter of copyright:
Compilations and derivative works
(a) The subject matter of copyright as specified by section 102 includes compilations and derivative works, but protection for a work employing preexisting material in which copyright subsists does not extend to any part of the work in which such material has been used unlawfully...
106. Exclusive rights in copyrighted works
Subject to sections 107 through 122, the owner of copyright under this title has the exclusive rights to do and to authorize any of the following:
(1) to reproduce the copyrighted work in copies or phonorecords;
(2) to prepare derivative works based upon the copyrighted work...
I highligthed the words. Source:
https://www.copyright.gov/title17/92chap1.html
OK, so a derivative work is one which is based on one or more prior works. Folds that are based in an existing model, that aren't the original fold, and have differences from the original, like size, type of paper, and color, among others, are derivative works. As the quotes mentions, derivative works that haven't been authorized by the copyright-holder of the original work, don't transfer the exclusive rights of the copyright-holder. That includes sales.
It's simple, if you created an original work, then the copyright protection is yours for the time being. There's the subject of transfering copyright ownership but that isn't the point here. If it's based in a copyright protected work and you didn't ask for authorization, then the copyright protection isn't yours. It's of the original author. If you obtained authorization or based it on a public domain work, then the copyright protection is exclusively over the significant new details you authored that weren't part of the original work. Finally, if there's a copyright-holder and it isn't you, then only he or she can sell and authorize sales of copies and derivative works from that particular work.
Now, a person could mention
fair use, but if the use of the copyright protected work has a commercial nature, then it isn't complying with one of the factors of fair use.