Offset printing help: Coating and lamination choices for catalog, brochure or other printed piece

Coatings and lamination choices for your printed pieces

Many printed pieces are designed to sell something (a product or concept) to someone. The appearance of the printed piece can play a big part. Sometimes a printed piece looks great coming off the press but then gets scuffed up in a brief case or in the mail. In other cases pieces are subject to more damaging environments such as outdoor applications, messy desks or restaurants.

Using a coating or lamination enhances the appearance of the piece and keeps it looking better over time. Most coatings and laminations are available in gloss, semi-gloss (satin) and dull. Creative uses of coatings will draw the reader to things of importance. Most frequently this is achieved by using a gloss and dull coating on the same piece.

A coating is a liquid that is most frequently applied on press as part of the printing process. Laminations are films that are applied in a post-press process. Each has strengths and weaknesses. This article will discuss each type and offer guidance as to which to use and when.

Think of using coatings or laminates in the following situations:

When the piece has a heavy coverage of a dark color of ink. These have a tendency to show fingerprints easily.
Pieces that will go through more involved binding processes such as stitching or perfect binding.
Pieces subject to a harsh environment involving grease, moisture or chemicals.
Higher end pieces where appearance can really make an impact.
Where durability is an issue such as book covers.

Coatings are quick and inexpensive
There are three types of liquid coatings: varnish, aqueous and UV. Each has different properties and uses.

Before I get into these, let’s examine two ways liquid coatings can be used: overall or spot. An overall coating is where the entire sheet is coated. This adds a gloss (or dull) appearance over the entire sheet. In a spot usage, only certain portions are enhanced. Frequently this will highlight photos. A typical use is to print a gloss coating over the photos and a dull coating over everything else. This dramatic difference highlights the photos. In the hands of a skilled designer this technique can be truly stunning.

Varnish is the most economical coating. It is really ink without color. Varnish comes in a gloss and matte (dull) version. The matte varnish has a tendency to mark easily. Varnish offers a little abrasion resistance but not much. It adds a measure of gloss, but not much. Varnish is a good option for pieces that have a short lifespan such as something given out at a trade show. It offers protection for a folded or stitched piece but won’t stand up to the rigors of perfect binding. Varnish offers no protection from grease, chemicals or water.

Aqueous coatings can be applied in a thicker coat than varnish. Therefore it offers more durability. It does not have any resistance to moisture or chemicals. It also changes the appearance more than varnish, whether it is gloss or dull. In its gloss form, an aqueous coating ads a somewhat "wet look. Aqueous coatings are well suited for reports and brochures. Like varnish, an aqueous coating offers no protection from grease, chemicals or water.

UV coating is the most durable and image enhancing liquid coating. The thickness yields a more durable and glossier end result. This coating is applied and then passed under an ultra-violet lamp which dries the coating immediately. This can be extremely useful on fast turnaround jobs. Jobs that are UV coated can be taken directly from press to the bindery without any dry time. The UV lamps dry the ink and the coating immediately. UV is the most expensive of the three liquid coating options. Use UV coatings on reports, brochures, catalog or book covers.

Film lamination offers greater durability and surface enhancement than liquid coatings. They are more expensive and usually add a day or so to the schedule. There is no such thing as a "spot application of film. However you can vary the width that is useful for presentation (pocket) portfolios. Film laminates offer varying degrees of resistance to moisture, grease and chemicals. Films are measured in thousands of an inch (mils).

Film lamination should be used for gloss sheets of a moderate to substantial thickness. Sheets can be laminated one or two sides. However unless you laminate with a nylon film, a sheet laminated on one side will curl, sometimes to a large degree.

Any film can be laminated to achieve a sealed edge. This is where the lamination on both sides of the sheet extends over the edge of the sheet itself. The lamination then forms a sealed border around the sheet. This forms a barrier to moisture and grease that is very useful in environments that would damage an unprotected sheet of paper. A good example is restaurant menus.

High-gloss laminates produce a very slick end product. Make sure that’s what you want. Your printer should be able to provide samples if you’re not familiar with it. Also note, high gloss finishes can make type hard to read, especially type 12 pt. and smaller. Matte or satin finishes are easier to read through.

Polypropylene lamination is the most affordable type of lamination. Poly is softer than other films so it is good for pieces that will be folded. Poly is available in gloss, satin or dull finishes. This is useful high-end brochures, catalog or book covers and short-term outdoor signage.

Polyester lamination is a harder material than polypropylene. They have very good heat and chemical resistance. They are very well suited to demanding uses such as repair manuals, shop catalogs, outdoor signage and in restaurants. Polyester comes in gloss, satin or dull finishes.

Nylon lamination is useful because is semi-permeable. That means it is less affected by heat and moisture. This translates to a sheet that doesn’t curl. Use this material on book covers when you need to laminate on one side but don’t want the sheet to curl. It’s also useful on other sheets when you only want to laminate one-side. Nylon is the most expensive of all laminates.

Not all coatings or laminates can be glued or written on. The glueing is important on presentation (pocket) portfolios and book covers. The ability to accept ink is most often needed during the mailing process. If your piece is going to be processed by a mailer and sent in the US Mail, please make sure the coating or laminate you intend to use will work.