Viscosity printing is a multi-color printmaking technique that incorporates principles of relief printing and intaglio printing. It was pioneered by Stanley William Hayter. The process uses the principle of viscosity to print multiple colors of ink from a single plate, rather than relying upon multiple plates for color separation. It is a fine art printmaking technique, making original prints in limited editions, as it is slow and allows too much variation between proofs to make large editions feasible. Color viscosity printing is among the latest developments in intaglio printmaking. Color viscosity printing was developed by a group working at Atelier 17 in Paris in the mid-1950s. This group included Stanley William Hayter, , Krishna Reddy, and .