A craze is typically considered a surface defect, developing most often in acrylic paints or mediums that when applied, begin to form a skin while the material underneath is still fluid and wet. The very flexible acrylic film can usually stretch quite easily as the edges of the skin begin to dry, requiring the center of the film to continue to stretch as water evaporates and the film shrinks. In some cases, the center areas of the drying film can no longer take the stress of shrinking and a tear in the upper part of the film occurs.

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At times the crazing phenomena can occur in very thin films. More often than not, this sort of crazed surface is the result of the lack of a coating being able to wet out the layer below. So as the stresses caused by the evaporation of water continue, areas where the cohesive force of the acrylic film is greater than it’s attraction to the substrate or paint layer below, you begin to see these same crevices in the film. In extreme circumstances this crazing can actually leave breaks in the film.