unbleached – Paper not treated with bleaching. It has a light brown hue.
uncoated – Paper that has not been coated.
undercolor removal – To improve trapping and reduce ink costs in the process color web printing, color separation films are reduced in color in areas where all three colors overprint and the black film is increased an equivalent amount in these areas.
underrun – Term refers to an order produced or delivered that is less than the quantity specified by the customer. Allowances are permitted in trade practices for under-runs.
undertrimmed – Trimmed to a size smaller than the specified trim size.
uniformity – Being uniform in the structure of the paper, the color and finish.
unit – Refers to the combination of inking, plate and impression operations to print each color. A 4-color press has 4 printing units each with its own inking, plate and impression functions.
UV – Ultra Violet radiation method of drying process color inks on high-speed multicolor offset presses.
UV curing – The drying of UV inks by a light reaction, rather than by heat and/or oxidation.
UV inks – In printing, solventless inks that are cured by UV radiation. They are used extensively in screen printing, narrow web letterpress and flexographic printing.
