Print Coatings: Varnish, Aqueous, Lamination, & UV

by Brock on September 30, 2008

umbrella

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.

Special Thanks – much appreciation to the classy folks at Ripon Printers for technical support on this piece. See their TechLines – Coatings Primer (pdf) for more information.

Image Credit: seanmcgrath

{ 14 comments… read them below or add one }

Gonnie Govender February 12, 2009 at 11:36 am

Can I put a Aqueous velvet soft touch over a laminate.

The process will be as follows
Print on PVC sheet, then put a laminate over the print. and then apply the Aqueous soft touch over the laminate.

Reply

Brock February 12, 2009 at 1:51 pm

Hi Gonnie, thanks for the question. First, PVC sheet sounds like a type of vinyl and we only deal with paper stocks. We are also not familiar with soft touch.

In our case, the answer would be no as the aqueous is done in line on press 1st and laminate off line last. Aqueous is for protection and the laminate is a high gloss film overlay also for protection.

I assume you are going for some type of look but unfortunately an appearance we are not familiar with. Sorry we are not able to be more helpful.

Reply

BASIL NAICKER May 13, 2009 at 12:26 pm

I AM CURRENTLY HAVING A PROBLEM WITH UV VARNISH (FLOOD COATING). THE UV FLAKES OR SCUFFS AFTER A WHILE. I HAVE TRIED MANY DIFFERERNT UV VARNISH AND UV SEALERS(PRIMIER). PLEASE GIVE ME SOME SUGGESTIONS.

Reply

Brock May 18, 2009 at 10:51 am

Hi Basil,

Thank you visiting our blog and for the comment. Unfortunately, there are too many variables to easily diagnose your problem. It is possible that the UV coating is under-cured, over-cured, or simply not biting into the stock.

If you are a manufacturer, we would suggest talking to your suppliers and to do some testing if this is a new offering. If you are a consumer, we would suggest contacting the manufacturer/printer. Good luck!

Reply

Jeff June 30, 2009 at 1:22 pm

Brock is right that there are a multitued of factors that could be involved with this UV flood issue.

In addition to the curing not enough or too much there could be bottom inks containing silicone. There are cationic UV inks that have a better ‘bite’ than regular UV inks.

I have also had a lot of luck with Aqueous coatings… The satin AQ is very versatile and is a great primer.

Reply

Brock July 2, 2009 at 11:50 am

Jeff, thank you for very much for sharing your experiences. Greatly appreciated!

Reply

jasmine November 1, 2009 at 1:47 pm

i would like to use clear high gloss varnish over print picture using beads/glitter or other decorative things to highlight certain areas.
any advice or info about classes or teachers you’d know.
thank you in advance for any feedvack

Reply

Brock November 6, 2009 at 11:31 am

Jasmine, thank you for the question. Gloss varnish is doable to high light areas – not aware of any additives for varnish to give a glitter appearance. I would suggest glitter or beads as more of an artistic application done by hand. Not aware of any classes or teachers in this area. Hope that helps.

Reply

Muzammil Hussain November 8, 2009 at 12:33 pm

Can UV coating be done on regular offset printing machine like Rota? How can it be cured after coating or some changes have to be done in Rota machine? Please suggest.
Thanks

Reply

Brock November 10, 2009 at 5:19 pm

Muzammil, thank you for the question. We are not familiar with “Rota” presses but UV coating is done in a similar fashion to screen printing – off line. We do not offer UV Coating because orders would need to be sent to a vendor specializing in UV Coating flat press sheets. Hope that helps.

Reply

Paul November 27, 2009 at 9:04 am

Does anyone know if UV coating gives any fading protection to the colours below. If something is on display over a year will the UV coating filter out UV too from fading the inks. Yellow seems to be the first colour to go.
Would appreciate anyones thoughts on the issue, Thanks.

Reply

Brock December 3, 2009 at 5:28 pm

Paul, thank you for your question. I suspect anything will fade over time, dependent on the light source, natural vs indoor lighting. One of our experts says UV coating and Aqueous coating do not yellow very much over time. Varnish will yellow fairly quickly over a short period of time. It will not protect ink from fading however, you would need to use light fast ink if printing 4/C process.

“UV Coating is a clear liquid spread over the paper like ink and then cured instantly with ultraviolet light. It can be a gloss or dull coating, and can be used as a spot covering to accent a particular image on the sheet or as an overall (flood) coating. UV coating gives more protection and sheen than either varnish or aqueous coating. Since it is cured with light and not heat, no solvents enter the atmosphere. However, it is more difficult to recycle than the other coatings.

UV coating is applied as a separate finishing operation as a flood coating or (applied by screen printing) as a spot coating. Keep in mind that this thick coating may crack when scored or folded.”

Source: http://www.printindustry.com/newsletter_18.htm

Hope that helps.

Reply

kunal Doshi March 29, 2010 at 5:35 am

Can someone please compare PVC LAmination V/s Aqueous coating.

Reply

Brock April 12, 2010 at 12:49 pm

Kunal, thank you for your question. Aqueous is applied much like an ink, water-based, protective coating in line on press. Not sure but believe the PVC lamination would be a like a film (thin plastic) coating which is applied offline. Both protect the sheet but – apples to oranges…for comparison.

Reply

Leave a Comment

Previous post:

Next post: