One of the larger, coffee table books that Plum Print produced, for example, featured 800-some photos of art. The company found that parents who use the site are likely to return.

Banks, who teaches in Chicago Public Schools, asks her students to use both print and online sources—books about the person they’re studying, but also web searches and online articles.

“At most they made a couple hundred copies and now I have one,” said Lukas, an associate professor of print and publication at UC Santa Barbara, who is on the organizing committee for Off Register, ...