Window graphics cover several quite different materials: solid self-adhesive window vinyl, clear and frosted films, static cling, and perforated one-way vision film. They are worth separating, because the answer to “can I coat it?” is quite different for each, and for one of them it is usually no.
Perforated one-way vision film
One-way vision film works because of its holes. The printed face is seen from outside, while people inside see through the perforations. A liquid coating, whether rolled, sprayed or applied by machine, tends to bridge or fill those holes. Once that happens, visibility from inside drops, and the effect the customer is paying for is compromised. Partly filled holes can also look uneven from outside.
For that reason we generally do not recommend liquid-coating perforated window film. Where perforated graphics need protection, particularly on the outside of glass or on vehicles, the usual approach is an overlaminate film made specifically for perforated media. If you still want to trial a coating, test it on an offcut and look through it from the viewing side in daylight before going further.
Solid and clear window films
Non-perforated window vinyls and films are more promising, but there are still points to check:
- Optical clarity. On clear or translucent films, a coating can show streaks, haze or roller marks when light passes through. Check against a window, not on a bench.
- Which face. Reverse-printed graphics read through the glass from outside; the ink side faces into the room. Coating the ink side can help against scuffs during cleaning.
- Adhesive. Keep coating off the liner edges and adhesive. On static cling films there is no adhesive, and coating the cling face would stop it working.
- Solvent sensitivity. Some thin films react to solvents with curl or distortion. Test on the exact material.
Sun through glass
Shop windows can get a great deal of sunlight, which is why UV protection is often the reason customers ask about coating window graphics. Colourjet includes UV inhibitors to help slow fading. Our guide to preventing fading explains the wider factors, including ink choice. For broader advice on displays behind glass, see window displays.
In short
- Perforated one-way vision: usually not suitable for liquid coating.
- Solid window vinyl: often workable, test first.
- Clear films and static cling: possible in some cases, with careful checks on clarity and the cling or adhesive face.
Window jobs often come with tight installation dates. If you want to check a material before you commit, call us on 01252 624 411 or get in touch through the contact page.