Guide
Most coating problems begin before the applicator touches the print. Trapped solvent, dust, fingerprints, cold materials or the wrong coating for the ink can all spoil a finish that would otherwise have been perfect. A few minutes of preparation is the cheapest quality control in any coating workflow.
Start with compatibility. Water-based coatings such as ClearShield are designed for water-resistant ink and media combinations, including solvent, eco-solvent, latex and UV inks. Paper, dye-based inks and other water-sensitive prints need a solvent-based product such as ClearJet. If you are unsure, read Landor’s overview of protecting inkjet prints.
Some surfaces have poor surface tension, notably UV inks and some rigid boards. In those cases Landor may recommend a primer, or a coating that doubles as a primer, to improve adhesion. Because inks and substrates change, Landor advises checking with them first on unfamiliar combinations.
A print can feel dry and still hold residual solvent or moisture. Coating too early can trap these volatiles and affect adhesion, appearance and long-term durability. Allow the print to dry, outgas and stabilise in line with the ink and media supplier’s recommendations. This matters most for ink systems that retain solvent, and for prints with heavy ink coverage.
Plan this time into the job rather than squeezing it at the end. If a print must be coated the same day it comes off the printer, raise it with the ink supplier and with Landor at the quotation stage, not when the client is waiting. Rushed coating is one of the most common reasons a protective finish fails to adhere properly or develops surface defects later.
Store prints that are waiting to be coated flat or loosely rolled, image side protected, in the same clean area where they will be coated.
The surface must be clean, dry and free from dust, silicone, grease, handling marks and application residues. Remove loose dust with a clean, dry, lint-free method that will not scratch an unprotected ink surface.
Work in a clean, dry, well-lit area with a stable temperature and little airborne dust. Fibres and debris become far more visible once sealed into a gloss or satin finish. Inspect the print under raking light before you start.
Bring the coating and the substrate to room temperature. Landor advises acclimatising both before use and curing water-based coatings at ideally no lower than 15°C. Stir the coating well, especially satin and matt products, but do not shake it. Lay the print flat and supported across its whole area, or, if a canvas is already stretched, make sure it is evenly tensioned and the frame is stable.
Before coating production work, coat a test panel using the same media, ink, image coverage and drying time. Ideally use an offcut printed at the same time. Once it has cured, check it for:
Landor’s starter kit exists for exactly this: testing coatings against your own media and substrates. Landor can also test and evaluate your application for you.
For repeat work, record the substrate, ink set, coating, finish, application method, coverage, drying time and conditions for each approved job. It makes quality easier to repeat and gives you a starting point if a problem ever appears later.
Follow the ink and media supplier’s guidance on drying and outgassing. There is no single figure for every ink; a print that feels dry may still need more time.
No. Household cleaners and silicone polishes can interfere with wetting and adhesion. Use a clean, dry, lint-free method and test anything stronger on a spare print first.
Sometimes. UV inks and some rigid boards have poor surface tension, and Landor may recommend a primer or a coating that also acts as a primer. Test first or ask Landor.
Paper is vulnerable to water, so Landor recommends its solvent-based ClearJet or ColourJet sprays for paper prints.
Call +44 1252 624411 or email info@liquid-lamination.co.uk for advice, samples and pricing.
