Every printing project is unique and has its own purpose. This warrants considering the addition of a coating in many cases. Sometimes coatings are added to give your piece an eye-popping Wow factor. Coatings can also give a piece a “finished” look by evening out the reflective qualities of paper and ink. And some coatings are added simply for protection against scuffing and fingerprints.
You will notice that several coatings go beyond visual appeal and bring the sense of touch into play. These tactile finishes are becoming quite popular and leave a lasting Impression on your audiences.
An Introduction to Coatings:
Let’s take a moment to make sure there is no confusion in case you are new to buying or designing printed products. Paper mills produce paper with added surface coatings which include gloss and low sheen finishes like matte, satin and dull. These are known as coated papers and they print best because there is little ink penetration into the paper. Ink sits and dries on the surface of the sheet resulting in less ink being used and sharper images.
The coatings we’re discussing here are added in the offset printing process after sheets have been printed. Coatings are most effective on coated papers because there is little or no penetration into the paper.
The following coatings are our most popular and you’ll see that in some cases they are used in combination with another coating.
Aqueous Coating is a water-based clear coating. It is used to protect printed pieces when added durability is a must. Brochures, booklet covers, and business cards all benefit from this coating. Because it provides excellent scuff-resistance, it is highly recommended for coating the non-address side of postcards. Aqueous coated materials are resistant to smudges and fingerprints. Thanks to being water-based, this is the most environmentally friendly offset coating.
Aqueous coating is available in gloss, matte and satin finishes. It should be noted that gloss aqueous is not as shiny as gloss UV.
This is the ultimate offset coating when you’re looking for POP! Those pieces you’ve seen with super glossy finishes are most likely UV coated. UV coating provides protection from smudges, scratches and fingerprints. UV printing and coatings are truly environmentally friendly. They are non-toxic and being cured by ultraviolet lamps on the press, they release no volatile organic compounds (VOCs) during the drying process.
Strike-through Varnish/UV & Reticulating Varnish/UV Coatings
These two coating processes produce very pleasing and dramatic effects. They provide the ultimate distinction when you want to accentuate certain parts of your pages, such as photos, graphics and logos. The processes for applying these coatings are similar, but with slightly different results due to unique properties of the varnishes used. Everything happens inline with both of these coating options, all in one pass through the press. First, the press sheet is printed, generally in CMYK in the first four press units. The sheet then proceeds to an additional unit where a matte/dull varnish is applied to all areas NOT to be accented with gloss UV. The sheet then continues its journey through the inline UV coating tower. It is here that the results change between these two processes, depending on the type of varnish that was applied.
Strike-through Varnish/UV coating
For Strike-through coating, gloss UV is applied to the entire sheet but is repelled by the varnish, showing only in the areas that were left unvarnished. A very dramatic difference in contrast results. The varnished areas remain matte/dull while the non-varnished areas have a high gloss finish.
Reticulating Varnish/UV coating
Reticulating Varnish/UV coating, sometimes referred to as chemical embossing, is created in the same way as Strike-through, except that a special reticulating varnish is applied to the printed sheet. A chemical reaction occurs when the UV coating is applied over this special varnish which results in micro beads forming everywhere the reticulating varnish was applied. The result is a tactile, tangible experience and it provides an interesting visual appearance, as well.
Design tip for these two coatings: The best contrast is accomplished when the the difference in sheen reflecting off the sheet is maximized. For example, let’s say you want a photograph to jump off the page. You will leave it unvarnished allowing it to be coated with gloss UV. However, as a worst case scenario, if the area surrounding the photo is white, even though dull varnish is applied, it will still be very reflective. This makes the contrast significantly less than if the surrounding area were a darker hue.
Soft Touch Coating
Soft touch coating is a velvety tactile finish that adds an elegant and luxurious appeal to any piece. Its flat suede-like finish looks as great as it feels! This coating is applied as a flood coat on top of the printed sheet during the offset process.
Soft touch has become a very popular coating for pieces like booklet covers, brochures and packaging. Excellent examples of using this coating are found in bookstores. Publishers often flood coat their book dust jackets with soft touch and it is not uncommon to find this coating combined with foil stamping.
UV Grit coating
This UV coating is another that appeals to the sense of touch. It has a fine grit added to take on the texture of fine sandpaper. Popular applications for this coating are sports- related materials and manufacturer’s catalog covers, though it could be used for a variety of other applications.
Varnish is applied to a printed piece in one of the press units and its application is similar to laying down a clear ink. It can cover the entire surface (flood) or just spots you want to accent. Flood varnish has pretty much been replaced by Aqueous and UV coatings. It is, however, convenient for spot accents because a plate can be made making this a less expensive option than spot aqueous or UV coatings.
Dry trap varnish is the process of adding varnish to a press sheet after the ink from the previous run has dried. The sheets are fed back into the press and coated with either a spot or flood coat of varnish. Two varnishes can be applied at the same time, usually a gloss and dull finish.
Available varnish finishes include Gloss, Matte and Dull.
When Should Coatings Not Be Used
If the printed piece needs to be written on, coating is typically discouraged. It is difficult to write with pencil and pens on all coatings. In the case of a postcard, coating the non- address side is fine. Many printer’s mailing departments can ink jet address on aqueous coating, but not on varnish or UV. Coating uncoated porous papers is generally ineffective because the coating will most likely absorb into the paper.
For assistance with your next commercial print project, contact Premier Print Group. Our experienced team is available to guide you through the best design applications for maximum impact on your printed pieces. Have a project in mind? You can request a quote here or reach out to our team with questions here. Get started today!