Definitions for "Cockling"
The phenomenon by which, when the relative humidity of the air is lower than that of the paper, the edges of stacked sheets dry out and contract (tight edges), causing the paper to buckle in the middle.
Wrinkling or puckering caused when paper, fabric, or any sheet of support material dries unevenly.
Wrinkling or puckering in paper supports caused by applying washes onto a flimsy or improperly stretched surface.
Keywords:  bubbling, comic, book, cover, surface
Bubbling on the surface of the comic book cover.