Cockle is an undesireable effect of puckering, warping, or rippling of paper after printing due to uneven surface, excessive humidity or oversaturation of paper with ink. It is more noticeable on thin uncoated papers with little cotton content. Subtle cockling may be apparent during printing when inks are wet, which may dry to a flat finish. Hot lamination can also smooth out slight paper ripples.
Cockling can be prevented on most stocks by keeping maximum ink limit (overlapping CMYK inks) below 300%, using a thicker matte paper (9+ mil) or selecting a resin coated photo paper or polypropylene media.