Print Coatings: Varnish, Aqueous, Lamination, & UV

Protection with Style

Why should I consider coating my presentation folders?

The two most common reasons for adding a coating over your folders are for protection and aesthetic reasons. Coatings are applied to protect printed folders from exposure to moisture, extreme temperatures, scuffs, scratches and frequent handling. They are also applied to draw the eyes to particular elements; to add depth and interest to your printed piece.

Four different print coatings are used in commercial sheetfed printing: overprint varnish, aqueous coating, lamination and UV coating (ultraviolet). All four are available in matte, dull or satin, and gloss formulations. Note that coatings perform differently on uncoated paper stock versus coated paper stock.

Overprint Varnish

Applying varnish is an inexpensive way to add gloss to your printed pocket folders. Although not as hard as other coatings, varnish does offer some protection; mainly resistance to dirt, smearing and water.

Varnish can be applied two ways; overprint/flood (applied over entire printed surface for protection) or spot/pattern (applied to select elements for emphasis). Varnish can also be color tinted.

Gloss varnish reflects more light and adds to the sharpness and saturation of images while matte or dull varnish increases readability by diffusing light and reducing glare.

This economical folder finish provides a mild shine and protection but can yellow paper over time.

Aqueous Coating

Aqueous coatings are fast-drying, water-based, protective sealants particularly resistant to smudges and fingerprints. Aqueous formulations afford greater protection than varnish and have gloss characteristics that fall between varnish and UV coatings.

A high gloss finish has less rub resistance and conversely, greater rub resistance reduces the degree of gloss. They are not water/liquid resistant because the cured coating does inhibit complete drying of the inks on the folder.

Advantage of aqueous coating over conventional varnish:

• Higher gloss
• Better clarity
• Faster drying
• Will not yellow with age
• Higher abrasion
• Higher rub resistance
• Environmentally friendly (water-based)
• Glossier finish on lesser grade papers

Laminate

Laminates come in two types, film-based and liquid-based. Either a clear plastic film is laid down over the sheet of paper or a clear liquid is spread over the sheet and dries (or cures) like a varnish. Laminates protect the sheet from water, are slow to apply and costly; but provide a strong, washable surface.

Film lamination features high gloss with a very smooth, tough finish. This durable plastic film has advantages over liquid coating at a slightly higher cost. Film lamination will not yellow with age, flake off, and is scratch resistant. In addition, the ink is protected from cracking and provides an odorless/wipeable surface.

UV Coating

UV coating is a liquid based, protective coating which is applied and cured by ultraviolet lamps leaving an extremely high gloss hard finish that is chemical and abrasion resistant. UV coatings are solvent free and emit no VOCs (volatile organic compounds).

Drying is instantaneous with exposure to ultraviolet radiation. Spot cover, raised effects and a very heavy coating for extra shine and protection are possible.

Advantage of UV coating over other coating methods:

• Highest gloss
• Better clarity
• Higher abrasion
• Higher rub resistance

Printing must be done with UV inks or inks that do not contain micro crystalline wax (also called wax-free). Pigments must be heat and chemical resistant. If nonresistant colors are used, the color may fade, change or bleed into unprinted areas.

It is more difficult to recycle than the other coatings and this thick coating may crack when scored or folded.

Other Considerations
Typically UV coatings and film lamination, often available from outside vendors, require additional time for drying of ink before coating and curing after coating. Typically aqueous and overprint varnish, often handled within the plant, do not require any extra lead time.

You will often find different manufacturers have different coating preferences and opinions as it relates to folder design. Typically these are based on in-house equipment availability, operator experience, and personal aesthetic preferences. While all four press coatings mentioned have advantages and disadvantage, there are situations where each shine. We would be happy to discuss them with you as they pertain to your specific folder printing project.

Image Credit: seanmcgrath