Was wondering if I was allowed to share scans considering that most I find are now either public domain or out of copyright.
If an authoritative source says it is "public domain" then you can share it. It may be problematic determining if the source is indeed authoritative. As far as out of copyright, how do you know? That too could be difficult to determine.
What do you mean by "public domain"? Do you mean it is available on the Internet? If so, then I'd say share the link.
I've found plenty of copyrighted material on the Interet, material that is almost certainly being used without permission (e.g. a recipe stating the source is some cookbook when I know the cookbook is copyrighted). I'm pretty sure CWS4322 means that you should post a link to the site with the recipe rather than posting the recipe itself. Then the copyright infringement becomes an issue between the copyright owner and the infringing website. Links by themselves are not copyright infringement.
This is not the safe side. If an item is copyrighted, you cannot share it legally. Providing the 'credit information' is merely a way of your saying, "I know it's copyrighted but I'm going to share it anyway." That can be used against you to prove you broke the law knowingly.
I agree, and this is a widely believed misconception, that copyrighted material can be used if the user gives credit to the copyright ownner. The only way that works is when it starts out "used by permission" and the person using it has received permission (usually written) from the copyright holder.
Well then, the posts that folks share where credit and (c) are included should also not be posted on this forum.
FWIW, it depends on the country in which you are in. In some, you can share 10% of the content without being in violation of copyright law and depends on how the copyright notice is worded and how one is sharing the information, e.g., for educational purposes, and where the book was printed. BTW, expressed permission, in Canada, means that you MUST have written, not email permission, from the copyright owner. And you must request it each and every time. At least it did the last time I asked my lawyer when I was asked to violate copyright law and refused to do so for a client (I also lost the client--but was that a client for which I wanted to work?).
Another misconception is that copyrighted material must have a copyright notice. Unfortunately that is not the case, although any smart copyright owner will attach such a notice.
Copyrighted material is often used on the Internet without permission, so absence of a copyright notice is no indication that it is not copyrighted. However, presence of a copyright noticed is a good indication that it is copyrighted.
A list of ingredients cannot be copyrighted. Whenever I want to refer to or quote a copyrighted recipe from the Internet I'll add my own description of what it is, post a list of ingredients, and then after "method" I post a link to the copyrighted site where the method can be found.
You should always assume a recipe is copyrighted unless (1) you created the recipe yourself, or (2) you have definite, reliable information that the article is in public domain or is otherwise not copyrighted.
BTW there is no 10% rule in the US. US law permits small quotes of material may be used for example in a book review. Quoting one recipe to "review" a book is
NOT a review, it's an attempt to work around the law and is in actuality a copyright infringement.
In the US here is the best source for answers to all copyright questions:
U.S. Copyright Office - Frequently Asked Questions