We recently talked about how foil stamping and embossing can make quite an impact on how a printed piece is finished. Coatings are another way, at least to us print nerds here, to really make ink on paper stand out in the crowd of boring, flat paper projects.
Coatings are clear substances which are applied to the press sheet after ink is applied. Coatings are also neat because they can protect a piece from scuffing and they can add an interesting gloss or dull effects to your printed piece.
There are three main types of coatings: varnish, aqueous coating, and UV coating.
Varnish is applied through one of the printing units of a printing press and comes in two basic types: gloss and dull. Varnish has some but not all of the protective capabilities that aqueous and UV have. Varnish’s advantage is that it can be applied in a “spot” application (not just over the entire sheet). Use this when you want to varnish only a certain area such as a panel or a photo.
Like varnish, aqueous coating is applied on a printing press although aqueous requires a special aqueous coating unit. Aqueous coating is, as its name implies, is a water based coating. It comes in three basic forms, gloss, dull and work & turn. (The work & turn version is designed to dry the press sheet and is not intended to change the gloss characteristics of a press sheet.) Aqueous coating is considered to have a better sheen and a more consistent surface (“lay down”) than varnish.
While it is possible to spot aqueous coat, it is very expensive and, as a result, most of the time aqueous is applied in a flood (covering the entire sheet). Aqueous is also routinely used to seal a sheet and, therefore, dry ink fast. This is particularly helpful on quick turn jobs because they can be taken directly to the finishing department.
UV Coating offers the highest gloss and the best protection of the three coatings. To achieve these characteristics, a clear liquid is applied to the press sheet and is cured with an ultraviolet light. The result is a very glossy effect. Like aqueous, UV is a flood application.
Sound interesting? Here are just a few things to consider when determining if a coating is the route you want to take:
- What kind of paper are you using? Different stocks react differently with different coatings.
- How will the product be used? Consider protecting the covers of a book if it is to be used over and over. Also, if you are worried about fingerprints, certain coatings can help to minimize fingerprinting.
- Do you need to protect your piece while is goes through the mail? Certain coatings help to protect your direct mail pieces by cutting down on scuffing by mail sorting equipment.
- If it is mailing, how will it be addressed? Some coatings are harder to inkjet than others.
- What type of ink coverage does your piece have? Consider coatings when heavy coverage is involved.
- Want a special look? You can combine spot and flood, dull and gloss and get an interesting contrast. You can even combine aqueous and varnish together (called a “strike through”).