Ten tips for printing on glass with a wide-format UV LED inkjet printer

TT Printing On Glass AS 176352015 1200×300

Ten tips for printing on glass

UV inkjet inks adhere well to many substrates, and there is an increasing demand to print on luxury materials for interior decoration, including real glass. Glass printing can be done on both flatbed and hybrid printers, yet good ink adhesion to glass is not self-evident. We give you ten tips.

Types of glass

You can print on three types of glass: float, tempered and laminated glass. The latter may no longer be defined as safety glass after printing because the bonding properties of the intermediate PVB film or EVA film change due to the printing process.

Humid spaces

Unprotected glass prints are not suitable for use in damp areas. If this is desired, the print will have to be protected by a transparent foil. In the case of, for example, a back wall in a bathroom, it can be sealed all around with an acid-free sealant.

Hygiene

Only touch the glass with cotton gloves and clean the glass with a lint-free cloth. Before printing, clean the glass with deionized water. For severe, greasy soiling, pre-clean with acetone.

Quality mode

Print in high quality – not only for the nicest result but also for the best curing of the UV ink. Use a printhead height of up to 1.3 millimeters.

Color profiles

Specific color profiles must be created for glass. Use a transparency meter such as a Barbieri or the latest X-rite i1. Note that it may be difficult to measure through the glass (as the light is diffracted). The thicker the glass, the more problematic. If the glass is thicker than 3 mm, we recommend making a profile on a thin Plexiglas or polyester foil to simulate the color effect on glass.

Use primer

A primer is necessary for good adhesion to glass. If the printer has a primer function, we recommend Agfa UV primer type 1051. The advantage of a digital primer is that primer can be applied exactly where the ink drops are placed. For printers without primer, we recommend the manual glass primer from IRIS. This is a good choice in terms of chemical resistance, adhesion, minimal residue, and ease of use. Apply the primer evenly with a lint-free cloth. Allow the primer to dry completely (approximately 10 minutes). Print within 8 hours of application.

Flexible inks

Use flexible inks with a wide color gamut. Print the colors and the white layers simultaneously for optimal adhesion.

Protective & block-out foils

Protect the print with a suitable foil with an acid-free adhesive layer. Use a blockout foil or black foil with a white glue layer to prevent light from shining through.

White background

You achieve the best color result and the right gray balance with a neutral white background. Therefore, cover the print with white ink. White ink has a neutral white point. A foil with a white or transparent adhesive layer often has a yellowish or bluish cast. This gives an undesirable result, especially in light tones.

Lighting

If you want a powerful image when the print is lit on the back – also know as the Day & Night effect – always use a white intermediate layer. The best effect is achieved with a variable pixel mask. Depending on the color density, more or less white is applied in the intermediate layer.

There is much more to say about glass printing. Think, for example, of various pre-treatments for chemical resistance and scratch resistance or post-treatment with a coating. We can tell and show you everything about it in Agfa’s Inkjet Competence Center and iME Lab in Mortsel (near Antwerp).

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