I am interested in scanning images of angels from recent books on religious art -- all printed within the last 20 years -- and putting them on greeting cards for resale. The artwork I want to scan was painted or drawn more than 200 years ago. Do I have to get the permission of the publishers of the books before proceeding?
To determine if you can use the angel images, you must consider two separate questions.
The art is in the public domain if it was published in the United States before 1923. Art is published for copyright purposes whenever copies are made available to the general public -- for example, photographs, postcards, prints, lithographs, castings from a statue, and other reproductions. Art is also deemed published if it was exhibited before 1978 at a place in which the public is permitted to photograph or copy the artwork. Chances are good that your 200-year-old angel artwork has been published and is in the public domain.
The fact that the sourcebooks are less than 20 years old will not matter unless this is the first publication of the art.
But you may face a second copyright hurdle. A photographer had to take a picture of the artwork for it to appear in the book -- and the photographer may claim copyright in that picture. As a general rule, you can probably copy a photo that is a slavish photographic copy of a public domain artwork. While the area is changing quickly, that is the latest legal word according to the court case Bridgeman Art Library Ltd. v. Corel Corp., 25 F.Supp.2d 421 (SDNY 1999).
However, this rule may not apply to photos of three-dimensional works such as sculpture, or photos of artwork where the photographer exhibits some originality in the lighting or composition (for example, a photo of the Mona Lisa that is lit it in such a way that only Mona Lisa's face was visible, not the background).
In many cases, photos of public domain artworks are in the public domain for other reasons; for example, photos published in the U.S. between 1923 and 1963 are in the public domain if they were not renewed on time.
The short answer, which you can see from this long answer full of loopholes, is that if the art is in the public domain and the photo is an exact duplication of the painting or fresco, you are free to copy the work.