Edges can be described in two ways: by the trimming (or lack of it) done to the paper itself, and by any treatment applied to the paper, such as gilding or a stain. This page illustrates edge treatments.

Gilded page edges.

Gilt. The page edges are smoothed and gilded. Sometimes all page edges are gilt, but often it is only the top page edges. Gilt edges offer more than a pretty look. The smooth surface protects the book from gathering dust over the years.

Page edges with publisher's stain.

Publisher's stain. A stain is applied to the page edges, usually just the top page edges, as part of the manufacturing process. Presumably this stain does something to shield the book from dust, or at least from darkening, although I have seen books where the publisher's stain seemed to make little difference. A frequent color is red, but green, blue, brown, mustard and probably other colors are sometimes used.

Marbled page edges and cover.

Marbled. The page edges are covered with a multi-colored swirl of inks. Marbling can also appear on end-papers and on covers, as shown in the picture.

Marbled papers were originally made by spattering and then swirling inks on a gel-like sizing medium and then laying the paper on top. The paper was then lifted off, carrying the ink with it. Modern marbled end papers are named for the pattern, not the process, and are generally lithographed.

The picture at left is courtesy of Kim F. Rasmussen, and shows a beautiful 1931 book from her collection.

Page edge sprinkled with red stain.

Sprinkled. The page edges are marked with small specks or spots. According to John Carter, in ABC For Book Collectors, most books bound in calf or sheep and made prior to 1850 had their edges sprinkled. Nowadays, this edge treatment is generally reserved for dictionaries and other reference books.

A similar effect was created by some publishers that spray-painted the bottom edges of their books with purple dye as a form of remainder mark no longer in use.

Untreated page edges darkened with shelf dust.

Unprotected edges. An example of a book with no page edge protection, darkened by shelf dust.