U

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

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

Undercolour Removal
Technique of making colour 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.