Metallic silver, fluorescent colours, clear gloss varnish and raised texture inks are offered on a range of eco-solvent, latex and UV-curable printers. They are bought for one reason: a visual effect that standard CMYK cannot give. Before coating these prints, the key question is whether the coating will preserve that effect or flatten it.
Metallic inks
Metallic inks contain reflective particles, and their sparkle depends partly on how those particles sit near the surface. A coating changes the surface the light hits first. A gloss coat may keep or even deepen the metallic look; a matt or satin coat can dull it noticeably. Metallic inks are also often less resistant to rubbing than colour inks, so protection can be genuinely useful, but the finish needs choosing carefully. Our guide to choosing a finish helps here.
Fluorescent inks
Fluorescent colours are known for fading faster than standard inks. A coating with UV inhibitors can help slow that, but it will not make fluorescent ink as lightfast as process colour, and customers should not be told otherwise. There is also a trade-off to test: UV absorbers that protect the ink may reduce the glow under some lighting, since fluorescence is driven partly by UV. Compare coated and uncoated samples under the lighting the piece will actually be seen in.
Gloss varnish and texture inks
- Spot gloss works by contrast with surrounding matt areas. An overall coating, especially a gloss one, can wipe out the contrast entirely.
- Raised texture is a relief effect. A liquid coat may settle in the low areas and soften the detail, and a roller can leave marks at ridges.
- In both cases, ask whether the specialty layer already gives enough protection, and whether a coat adds anything the customer wants.
Compatibility still applies
Specialty inks belong to the same ink family as the printer’s colour set, but their formulations differ, so do not assume a coating that suits your CMYK will suit the specialty channel. A solvent coat may react with some of them. Coat a test that includes the specialty ink at full density, the CMYK beside it, and any areas where they overlap. Check adhesion, look for any change in colour or effect, and repeat the check after a few days. Our sample testing guide gives a simple routine.
Sometimes the right answer is to protect the work another way, such as framing, or simply to leave the effect uncoated and explain the handling limits to the customer.
If you are planning a run with metallic or specialty inks and want advice on whether to coat, get in touch through our contact page or call 01252 624 411. A printed test piece makes the conversation far more useful.