Dover Pictorial Archive
Most collage artists are well familiar with the Dover Pictorial Archive, a series of clip art books featuring public domain art (usually engravings) produced by Dover Publications. The Dover Pictorial Archive provides a wealth of source material. However, they do place some limits on commercial use.
It might not seem right that Dover would restrict use of the art in their books. After all, how can they place limits on use of public domain images? Public domain is public domain, right? The answer is that each Dover book is a derivative work (remember that term?). The individual images are public domain, but the collection is copyrightable by Dover. They are able to charge licensing fees for extensive use of their collection, to compensate them for the work they have done in compiling the books.
That said, Dover's licensing agreement is very easy for a collage artist to work with. I called them recently to inquire about this. They told me over the phone that they allow free commercial use of 10 single images from each Dover book per project. If the images are to be used in collage, they allow free use of 10 images from each book per collage -- no matter how many collages are in the project. Even my current project, a Tarot deck with 78 collages! It's easy to imagine how much a collagist can do without any question of a fee. The fee is minimal as well -- only $5 per image.
Even so, any artist who finds this agreement too restrictive is welcome to do their own research, find the original images in antique books and newspapers, and then use as many as they like without owing Dover anything. In fact, I do a fair bit of this sort of research myself, to find images that are not in Dover books. Many of the best Dover images have become recognizable, and I like the distinctive flavor it gives my work to have unique engravings. I have come across the original version of a number of Dover images along the way, so it is possible to find them. However, Dover does not publish the names of the books and magazines from which they draw their source material. So searching for their images feels like looking for a needle in a haystack. But if you really feel the need to duplicate Dover's work, by all means have at it.
When doing original research, I recommend keeping a file with an extra photocopy of every original image you use, including the publication, date and page number. You'll probably never need it, but if there ever were a question about your sources, it would be a good thing to have. You may think that you'll remember where each image came from without needing to write it all down. Believe me, you won't.
I have recently exchanged email with Rosa Lopez, who handles rights at Dover. She has confirmed their policy -- no fee or permission required for up to 10 images from each book per collage, even if there are multiple collages in one project. She has promised to provide me with a written statement for this page. When I receive it I will post it here.
In the meantime, she encourages artists who are using material from the Dover Pictorial Archive to write to her at firstname.lastname@example.org or email@example.com. Contact her if you think you might need permission, or if your publisher requires documentation. Ms. Lopez asks that you provide your mailing address and/or fax number so that she can send the permissions form right out.
One thing to note: not all books published by Dover are part of the Dover Pictorial Archive series. They also publish a number of books about science, literature, art, history and a variety of subjects, which are under normal copyright. When you buy a Dover book to use as source material, be sure it says "Pictorial Archive" on the inside front cover. As far as I know, all the clip art books are in the Pictorial Archive.