Print protection coatings fall broadly into two families: those that use a solvent as the carrier, and those that use water. Colourjet is a solvent coating. We think it is the right choice for a great deal of large format work, but it is not the right choice for every print, and it helps to understand why.
How they work
Both types carry protective resins onto the print in a liquid, which then evaporates to leave a clear film. The difference lies in that carrier. A solvent evaporates and can interact with the ink and media surface as it does so. Water evaporates more slowly in most conditions, and can be absorbed by porous media and water-sensitive inks along the way.
Where solvent coatings tend to do well
- Producing a tough, water-resistant layer, which is why Colourjet protects against water, chemicals and abrasion.
- Working over non-porous media such as vinyl and banner, where a water-based product may struggle to wet out evenly.
- Covering prints from eco-solvent, latex, UV and pigment printers on suitable media.
- Avoiding re-wetting of water-sensitive inks and receiving layers.
Where solvent coatings need care
- Some dye-based inks can bleed or shift under solvent.
- Some uncoated or swellable papers, foam boards and plastics can react.
- Good ventilation is essential, and you should always follow the product’s safety data sheet.
The case for water-based coatings
Water-based coatings generally have lower odour, which some users prefer in shared workspaces, and can be gentler on solvent-sensitive substrates. On the other hand, water can disturb water-sensitive inks, particularly dyes, and may cause cockling on some papers. They may also take longer to dry in cool or humid conditions. As with solvent products, performance varies a great deal from one formulation to another, so generalisations only go so far.
How to decide
Start with the print, not the product. Ask three questions:
- What ink is it? Pigment, latex, UV and eco-solvent prints usually suit a solvent coating well once dried; dye prints need testing either way.
- What media is it? Non-porous media often favour solvent; very absorbent or solvent-sensitive substrates need careful testing.
- Where will it live? Outdoors, wet areas and frequent cleaning call for strong water and chemical resistance.
Whatever you choose, a sample test on the actual print is the only reliable answer. Our guides cover testing and application, and our coatings page explains Colourjet and Landor Liquid Lamination.
If you are weighing up coating types for a particular job, talk to us on 01252 624 411 or email info@landoruk.com. Better still, send a print and we will tell you how it responds.