Printing with UV Inks: An Update
When I was in my early years as a designer, back in the 1980s and ‘90s, UV coating was a big thing. You could coat a book cover with this glossy liquid, and it could be cured instantly with ultraviolet light. Since most inks and coatings back then had to dry through oxidation, absorption, or evaporation, immediate curing using light rather than heat was rather exciting to me.
Now, technology has moved forward, and UV inks are all the rage for the same reason—and more.
Although these are not new, they are very useful in that UV inks allow you to print on almost any substrate that will fit in a large-format inkjet printer. This includes wood, aluminum, glass, and any number of other materials that are either porous or not porous.
This is because the ink can adhere to and sit up on top of the substrate. With conventional inks, the ink mixture seeps into (and adheres to) the paper fibers. This dulls back the color of the ink, and the ink needs time to dry. However, once dry, conventional inks do have a long life.
But with UV inks, you get a lot of other benefits as well:
1. You can use less pigment, for instance. Since the inks sit up on the surface of the substrate, all of the ink can reflect the ambient light. This means less ink is needed. And this cost savings can add up.
2. The inks look better because they do not dull down when they cure. They are crisper, and they hold their brilliance. This means not only that they look better but also that they are more likely to be accepted by the printing clients. Therefore, there has been a reduction in the overall rejection rate of jobs printed with UV inks, which also adds up to a substantial savings.
3. Looking better goes beyond the brilliance of the inks, as noted above. Since the inks cure instantly, it is possible to maintain the gloss of the ink and hold much finer detail in imagery. Inks don’t smear or run, so small details are visible, and this is perceived by viewers as higher quality printing. Therefore, such luxury printing as food, fashion, and automotive promotional materials look much better, and this significantly benefits advertisers.
4. UV inks release no VOCs (volatile organic compounds) into the atmosphere. Traditional inks include solvents in their mixture, and as these inks dry, the molecules of the ink vehicle (that which makes it a liquid) are released as a gas. Traditional inks are therefore less environmentally sound than UV inks, which emit no VOCs because they dry (cure) instantly when exposed to UV light. This benefits not only the environment but also the health of people in the pressroom (because there are no fumes to breathe in). In addition, because UV inks cure instantly, there is no need for anti-set-off powder between press sheets (to keep them from sticking together), and this also saves money.
5. Traditionally printed inks need time to dry, as noted above. If you’re printing on both sides of the press sheet, which is usually the case, this means you sometimes need to wait for days to print the back of the press form. Or, you have to wait after printing the second side of the sheet before finishing the job (that is, before folding, trimming, etc.). Jobs that have post-press work done before the traditional inks have dried sufficiently will mark, or the ink will offset (the ink will be transferred from one press sheet to another, rendering the printed sheets useless). So not only does the use of UV inks speed up the entire printing and finishing process, but it also significantly reduces overall spoilage from ink offsetting.
6. Not all traditional ink is allowed to air dry. Some is dried with heat, and this heat costs a lot to generate. (Plus, compensating air conditioning is often required, which is also expensive.) In contrast, the lights used for UV printing are LED or mercury/quartz, which means they do not generate the kind of heat used to dry traditional inks.
7. UV inks are more durable than traditional inks. This means they are more resistant to scratching and chemical abrasion because they dry (cure) to a harder surface than traditional inks. Interestingly enough, they are also more resistant to weather damage and are more light fast (less likely to fade), plus they are more flexible (more elastic and less prone to cracking and breaking). All of this makes them ideal for outdoor signage.
8. In addition, the durability of UV inks (in terms of resistance to scuffing, weather, and sunlight) means signs don’t have to be reprinted as often, and this saves a lot of money.
The one thing to keep in mind as a print buyer is that not all printers use UV inks, since they require special curing technology in the printing plants. In addition, UV inks can be more expensive than traditional inks, but over time I expect this will become less of an issue as the technology is adopted by more and more printers. For now, my view is that if you pay a little more at the printing stage, you still reap savings in terms of the longevity of the product and the overall higher quality of the printed work.
Think Ahead with Logo Design
I’m designing a logo for an asphalt company. As a designer, my first thought was to produce numerous mock ups to put my ideas down in physical (or virtual) form. Because of this, I grabbed the tool with which I am the most comfortable: InDesign, not Photoshop or Illustrator.
Now there’s nothing inherently wrong with this approach. I knocked out multiple iterations quickly because of my facility with the program. InDesign is like an extension of my hand and brain. I don’t have to think in order to use it. Therefore, I can focus on the design rather than the computer program.
That said, once I started discussing the logo use with the large-format vehicle wrap printer, the representative reminded me that I would need to submit vector art. I knew this, but in the heat of the design moment, it had slipped my mind.
What this means is that I will need to provide artwork for the type in a format that can be enlarged or reduced with no loss of quality. To do this, I will use what is called vector art (PostScript curves based on mathematical formulae) rather than raster art (also called bitmap art). Raster art is composed of dots on a matrix or grid, not mathematical formulae. Because of this, it cannot be enlarged without pixellation and loss of detail.
If you’ve used a scanner and then tried to further enlarge the resulting scan, you’ll know what I mean. The pixels that comprise the final art get larger and larger (i.e., become visible) as you enlarge the scan, so the quality of the art diminishes. When you use vector art, in contrast to raster art, you can enlarge the logo (in my case) to whatever size is needed with no loss of detail, fuzziness, or pixellation. Then, when the PostScript RIP (raster image processor) finally does convert the PostScript curves (the mathematical formulae) into a printable matrix of dots, it will do this at the highest possible resolution, at the final size needed for the art. This will result in no loss of detail or pixellation because it will happen after (not before) the enlargement.
In my case, what this means is that I can create one logo and then use it for my client’s business card and letterhead (a very small logo rendering) and then also use it for the large-format printing of the vehicle graphics for his van (a very large logo rendering).
However, this will entail some work after he responds to my initial designs. Once he has chosen a version he likes (or we have created other versions based on his suggestions), I will need to recreate the logo in a drawing program (Illustrator, in my case). This will be the best program in which to convert the editable type into outlines only. To these outlines of the letterforms, I can then apply strokes (color and thickness for the outlines of the letterforms) and fills (the interior color of the letterforms).
A final issue will be the resolution of the photos. For smaller images that will be used for brochures, letterhead, etc., I will need any halftone images to be 300 dpi in resolution. However, for the vehicle wrap, which will be much larger than the business identity package, I will need to defer to the signage printer. After all, signs (such as vehicle wraps) are viewed from a greater distance than are envelopes and letterhead. Therefore, the image resolution can be lower without the viewer’s actually seeing the halftone dots in a photo.
That said, the large format vehicle wrap printer has made it clear that they will need an EPS (Encapsulated PostScript) file for the logo created in Illustrator (or a comparable vector program). So at some point I will need to turn my attention from creating the logo (as a design project) to producing it as high-resolution, print-ready art.
[Steven Waxman is a printing consultant. He teaches corporations how to save money buying printing, brokers printing services, and teaches prepress techniques. Steven has been in the printing industry for thirty-three years working as a writer, editor, print buyer, photographer, graphic designer, art director, and production manager.]