The first thing you have to know about decorating glass is that there are two ways to print on glass: digital inkjet and screen-printing.
Screen-printing is ideal for mass production of thousands of identical panes of glass. Wide-format inkjet printing (digital inkjet) is for custom printing of one to a few hundred customized works of art on glass. Since our main interest is digital printing we will focus directly on this technology.
Glass is nonabsorbent and transparent so applying a digital printing technology had to be adapted to overcome the challenges presented by the glass itself.
There are two methods for digital printing on glass:
- Ceramic frit (Digital ceramic printing)
Digital ceramic printing inks (Ceramic Frit) contain nano-particles of glass mixed with colored pigments that are fused into the glass (fired or tempered) after printing to fuse the inks with the glass, so the inks become an integral part of the printed glass.
A successful firing of the glass and ceramic ink will result in a bubble free layer of constant thickness and homogeneous pigment dispersion within the glass.
Digital UV printing employs ultraviolet light to dry the ink on the glass surface. Digital UV printing is a fast and economical method for printing customizable images on glass for short-run applications.
Pros and cons: Ceramic frit vs UV-cured inks
- Ceramic frit inks uses spot colors. UV-cured inks use CMYK.
- Ceramic frit inks are printed onto the ceramics before firing. Baking is required as the ink is still very wet after printing. The advantage of these is that they can potentially last 10 years outside.
- UV-cured inks are printed onto the finished surface of the tile (after firing). UV-curing inks are always advertised as being able to print on ceramic tiles. If you heat UV-cured inks for glass in most cases the UV-cured ink will lift up and peel off easily. You don’t even have to scratch it; the ink layer will simply become separated from the surface because the tile is changing size after being heated and cooled.
- UV inks are not fused into the glass the same way ceramic inks are; they are laid down on top of the glass and then cured; creating an ultra-thin printed layer on top of the glass surface.
The technology of digital printing has reached the glass industry, giving the homeowners the option to personalize their homes. The flexibility of digital printing on glass opens a new world of options, and compelling advantages for glass processors, architects, and designers.