UV Printing — Horse of a Different Color

THINK OF a sheetfed offset UV press as a chemistry set for grownups, complete with an ever-shifting set of variables and a hands-on learning curve. The upside of that curve is the license to print an endless range of special effects impossible to achieve with conventional inks and coatings.

And the downside? There isn't one, according to a growing number of practitioners that may have assayed the market with a vague notion of value-added, then stayed once it became apparent what a mastery of UV techniques could mean to their competitive position and their bottom line.

UV printing is not for the faint of heart, and competence comes at a price measured not only in dollars, but also in the discipline needed to stick with a process that sometimes seems to have more in common with snake wrangling than with conventional printing. Even the most experienced and committed practitioners admit to hitting a few speed bumps along the way.

Chief among many compensating advantages, however, is the fact that UV capability is a key differentiator in the overcrowded 40? sheetfed market because it enables printers to win jobs that the competition can't. And that's priceless.

(Note: For purposes of this article, UV printing and coating is used to denote in-line UV printing and coating.)

In UV printing, specially formulated inks are exposed to ultra- violet radiation, which causes them to harden instantly on top of the substrate. The result produces high levels of gloss or dull coating, vivid color and vibrant detail with superior rub resistance and no post-cure dryback--even on soft, uncoated sheets--making UV the technique of choice for applications like luxury cosmetics and chic wine labels.

Assuming they have the right viscosity and density, and will perform well with very little water in the fountain solution, UV inks cure quickly, meaning that products can be finished more rapidly, enabling higher throughput and fast turnaround, even on two-sided jobs. In-line UV printing is notable for the superior results it can achieve on difficult substrates, from uncoated paper and board to foil and especially plastic, including synthetic papers, static cling vinyl and lenticular. The ability to "lay down" layers of opaque white or metallic, and then print over it in a single pass, merely hints at the versatility of the UV process.