looking for open digital collections

Because I have a project coming up that will need lots of pictures of early printed books, I’ve been trying to compile a list of openly accessible digital collections of early printed books. Sound like a straightforward project? You might think it’d be pretty easy to identify whether a digital collection has terms that are useful for your purpose. You’d be wrong. Some collections have clearly stated terms and link to those policies in obvious ways. My favorites are those providing that information with the items themselves—both because of their ease of use and because they allow for item-specific information, which is handy given confusing copyright regulations and diffuse collections. But there are also places that use a cover-their-butts note instead of providing user friendly information. Statements along the lines of “we obey all relevant copyright laws” might protect a library from the risks of wrongly stating whether an item is not or is under copyright, but they do nothing for…