Term: Cockling

Surface distortion that occurs on watercolor paper when washes are applied to flimsy or improperly stretched supports. Cockling can also occur when paper is stored in a humid environment. Cockling is most prominent when the paper is not uniformly wet. When this happens the fibers in the wet areas expand while those in the dry areas do not. This inconsistent expansion deforms the surface of the paper producing irregular peaks and valleys. The distortions may appear as wrinkles, puckers, ripples, creases or warping.

Cockling can be prevented by using higher weight paper, applying less water, or by stretching the paper and securing it tightly to a rigid board before painting.