Coatings: Varnish, Aqueous, or UV- what’s right for my project?

April 18th, 2011 | Posted by garry in Uncategorized

XtraCoat UV Machine, UV is very effective for the right scenario or application.

Over the many years I’ve been involved in publishing, or printing projects orchestrated primarily for marketing or agency folks; coatings (or which type of coating to use?) have come up on a number of occasions. Occasionally I hear strong preferences from the client on one technique over another, but sometimes these determinations are not necessarily based on reliable information.

So this post is to touch on the basics of the most popular types of coatings, and their pros and cons, especially in relationship to each other. I’ll cover them beginning with the most economical, and ending with the pricier (but more limited) applications.

Varnish: Typically a clear coating, oil or solvent-based and used frequently in offset printing, there is gloss varnish, dull varnish, and varnishes may be tinted with certain inks. Unless you have significant experience in tinting, or can afford a press-test before production; I’d recommend not experimenting with tint varnish.  It’s difficult to predict outcome accurately, and very expensive to be on press and decide you’re not happy with it at that stage.

There are two common reasons varnishes are used, first is protection from scuffing, or fingerprints, especially if a piece will be handled a lot. An overall varnish is often used to also enhance the gloss on a given sheet (gloss varnish on gloss paper), or tone the gloss down in same cases, with a dull varnish on a gloss sheet.

A second reason would be utilizing varnishes to visually high-light certain graphic elements. An example is: making a graphic “pop” off the sheet by hitting the image with gloss, and applying a dull varnish behind it, providing contrast or adding a sense of depth.

There is inline varnishing, which is using a unit on the press, following the preceding colors. Offline varnishing is typically referred to as “dry-trapping”. This would be an intentional request, only when using both gloss and dull for technique or effect as described earlier. Many shops with 6-color press equipment will run both varnishes in-line, unless specifically requested to dry-trap.

Varnish, in my humble opinion is not as effective at protection as some might be led to believe, however it’s typically the most cost-effective coating. Another disadvantage, is over time, varnishes will often “yellow” the paper or hurt its brightness.

Aqueous Coating: Water based protective sealant, with gloss and satin options, most frequently utilized inline, or built in with many of the current presses in sheet-fed print production.

In today’s production world, aqueous coating is the more popular or preferred method of protecting a piece, better suited to protect than varnish, and usually it will add a higher level of gloss. In addition to this, it won’t yellow a sheet in time. Finally, a big key is that it dries very quickly, allowing shops to quickly get rush print projects into bindery faster, eliminating the chance of off-setting during cutting, or marks when folding. Aqueous is better suited for overall coating, than spot coating in most cases, but there are limited exceptions, depending on equipment.

UV Coating: UV coatings are applied basically as a liquid that is then exposed to ultraviolet lighting, to instantly harden or seal the coating to the sheet.

There are a number of finishes available, depending on the shop or the specific equipment or work-flow. Some basic, but very effective coaters will only do an overall application of either high gloss, or matte/satin finish, but for book or magazine covers- that’s a perfect fit or all that’s needed.

Higher-end equipment or certain workflows are designed to facilitate spot applications, but be cautious of unrealistic registration expectations, especially with very detailed graphics involved. (It’s easier to do tight register of gloss/dull varnish on press, but the UV is much more effective at protecting and has a much higher “gloss factor” than varnishes.)

There are additional choices in finishes available with certain high-end finishing operations, but the more exotic the choices, generally the higher the cost. While UV instantly dries, generally it adds more time to a print project overall.

Finally, for absolute protection or extreme durability- consider lamination. I generally would recommend lamination only for single sheet applications, examples might include posters that will be hung for any amount of time, restaurant menu’s, or book covers that are wiro or spiral bound, and that need that extra durability factor. Make sure to allow extra time for laminating in particular. All of these options and others should be discussed with your rep in advance if at all possible.

If you have any questions, or would like to see samples of these techniques, or discuss which coating is appropriate for your next custom project, simply contact Go Promoting and we’ll look forward to speaking with you!

Todd Farley, all rights reserved, ©2011

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