Uncoated Paper - Paper that has not been coated with clay. Also called offset paper.

Undercolor Addition - Technique of making color separations that increases the amount of cyan, magenta or yellow ink in shadow areas. Abbreviated UCA.

Undercolor Removal - Technique of making color separations such that the amount of cyan, magenta and yellow ink is reduced in midtone and shadow areas while the amount of black is increased. Abbreviated UCR.

Universal Copyright Convention (UCC) - A system to protect unique work from reproducing without knowledge from the originator. To qualify, one must register their work and publish a (c) indicating registration.

Unsharp Masking - Technique of adjusting dot size to make a halftone or separation appear sharper (in better focus) than the original photo or the first proof. Also called edge enhancement and peaking.

Up - Term to indicate multiple copies of one image printed in one impression on a single sheet. "Two up" or "three up" means printing the identical piece twice or three times on each sheet.

UV Coating - Liquid applied to a printed sheet, then bonded and cured with ultraviolet light.