Sun-fading occurs when the color of a book's cover or spine is lightened through extended exposure to ultra-violate light. It happens to both jackets and books.

Sun-fading on cover.

The picture at left shows a book with a distinctly lighter area along the top of the cover. This resulted from the book either laying underneath something or being shelved next to a shorter book for a considerable period of time. The darker portions of the cover were shielded from the damaging effects of the sun.

Sun-fading on spine.

More common is for the spine to become faded while the rest of the cover remains pristine, as occurred to the jacket at left. Often, the fading to the spine is so uniform that it almost seems to have been published that way. A close inspection of the margins of the color change will reveal a difuse border, rather than the sharper line that would have occurred if the publisher had intended the spine to be lighter. Another tell-tale sign in the photograph at left is the darker orange bridge that remains at the foot of the spine.