We are continually seeking to grow and improve this glossary, so if you spot any definition you do not agree with, a term that is missing, or have any comments in general, please email our reference team.
| Uncalendered | Papers that are not smoothed by going through the calendering process |
| Uncoated Paper | Paper that has not been coated with clay. Also called offset paper |
| Undercolour Addition (UCA) | Technique of making colour separations that increases the amount of cyan, magenta or yellow ink in shadow areas |
| Undercolour Removal (UCR) | 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 |
| Underside | Surface of seb paper which receives the impression of machine wire on papermaking machine |
| 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 |
| Upright | A term given to books bound on the longer dimension |
| URL | Uniform Resource Locator, i.e. the address of a Web page or other Web resource |
| USB | Universal Serial Bus. A standard connection between computers and peripherals such as mice, keyboards, printers, hard discs and scanners |
| User Interface | The point at which the user interacts with a device or piece of software viewed on a monitor |
| UV Coating | Liquid applied to a printed sheet, then bonded and cured with ultraviolet light |
| UV Ink | In printing, solventless inks that are cured by UV radiation. They are used extensively in screen printing, narrow web letterpress and flexographic printing |