Custom Printing: How Do They Print Ceramic Tiles?
A prospective client recently asked about inkjetting ceramic tiles (or more specifically, about inkjetting tiles with UV ink). Since I was a little rusty on the subject, I went to school on ceramic tile printing.
For one thing, this is a big niche within the commercial printing industry. A great number of the large ceramic tile printing suppliers are in Italy, interestingly enough. And due to recent advances in digital inkjet printing, it is now easier than ever to produce intricate, beautifully printed tiles for your floor, wall, or just about anywhere else.
A History of Tile-Printing Technologies
Prior to the advent of digital commercial printing, tiles were decorated in one of three ways: screen printing, rotocolor (printing with a series of rollers with patterns on their surfaces), and appliques.
To put this in context, let’s consider the types of designs printed on the tiles. For the most part they were simulations of other materials. For example, tile designers would print stone patterns, such as the natural surface patterns of marble, on the ceramic tile blanks. To a good extent, this was because a ceramic tile floor would be much less expensive to prepare and install than flooring made of the actual stone.
Here are some of the pre-digital custom printing options in more detail:
Screen Printing
First a tile designer created a pattern (presumably a simple design). Then she or he attached a block-out film to a nylon (or even metal) screen suspended from a wooden or metal frame. Those areas that would print, the designer would cut away from the film, leaving the non-printing areas of the stencil intact.
The screen frame was then attached to a base using hinges that would allow the screen to be raised or lowered. The designer would position the unprinted tile on the base, lower the screen over the tile, and load printing ink across the width of the frame, horizontally, at the very top of the screen. Then, using a rubber squeegie, she or he would drag the ink downward across the substrate (the tile). Ink would go through the screen where the stencil material had been removed, printing the tile. And ink would be blocked where the stencil material was intact.
Eventually, photographic technology was used to chemically create this stencil (rather than hand-cutting the film), but the process was essentially the same. Individual tiles, or groups of tiles, were printed with ink forced through the screen.
A designer had to repeat these steps for each color. This process required a lot of set-up work, so it was best suited for longer print runs.
Rotocolor
If you look at videos of rotocolor work online (which started to be popular in the 1990s), you’ll see that it looks a lot like offset commercial printing (flat material being transported under a series of rollers). However, this is a relief process, in which a series of rubber rollers lays down the inked pattern on the tiles as they pass (under the rollers) on a conveyor belt. This became the preferred method for decorating tiles, when compared to screen printing. Among other things, it allowed for more variety and less image repetition from tile to tile.
White-Toner Printer Transfers
Other vendors printed powdered toner on vinyl, which could then be attached to the tile substrate. However, any areas they didn’t want to print (to allow the actual tile to show through), they had to “weed.” Essentially this means picking away the vinyl material using a sharp tool, like a dental pick.
Digital Dye Sublimation
This actually fits into the digital realm. It is relatively new, compared to the centuries-old technique of custom screen printing, for instance. For this process, the design or pattern is printed (via inkjet) onto specially treated paper using specially treated inks, and heat turns the solid ink directly into a gas, which is transferred onto the tile substrate using heat and pressure. Unfortunately, sublimation works well primarily with white or lighter colored tile blanks. It also works only within a small area compared to the larger format of other tile-decoration processes.
The Overall Assessment
In almost all of these cases there are limitations, including:
1. The repeatability of the pattern (how often the same pattern shows up on the tiles).
2. How large the printable area can be.
3. How time- and labor-intensive the make-ready process will be.
4. The detail of the printable image (simple patterns vs. photographic detail).
If you’re producing a wall-sized mural, these can be important concerns to address.
Other important considerations pertain to durability. If you print on floor tiles and foot traffic wears away the pigment you have applied, the process is a failure. Or if sunlight and time cause the printed image to fade, that’s a disaster. Ideally, you need to use true ceramic pigment that can withstand the firing of the kiln (1600+ degrees Fahrenheit) along with any covering glazes. Only in this way can you be sure the designs on your fireplace tiles, bathroom tiles, shower tiles, or floor tiles will last a long time and tolerate sun, moisture, foot traffic, whatever.
Inkjet Printing: Increasingly the Best Alternative
In all of my research I found a common thread. Due to the advances over the past couple of decades, inkjet printing has become the preferred technology for decorating ceramic tiles.
1. Unlike screen printing, the make-ready is minimal. You don’t need to set up and clean up screens for multiple colors.
2. You can achieve photographic detail. This sets inkjet custom printing apart from all of the other options, given the achievable resolution (and hence detail). This is even beneficial when reproducing the nuances of natural stone patterns.
3. Unlike many of the other options, you can print all the way to the edges of the tile blank.
4. Unlike rotocolor and custom screen printing, you don’t need to worry about images repeating too often. In fact, you can vary all images infinitely.
5. You don’t need to worry about size (an issue with all of the preceding technologies, including sublimation). You can print the tiles on a grand-format flatbed press, which will allow for much larger images.
6. Due to the almost negligible set-up for the digital inkjet process, there’s no need to print long runs of tiles and then store them. This reduces the need for inventory and for the storage of rollers, silk screens, and similar supplies.
7. Unlike sublimation, you can successfully print on darker tiles as well as lighter ones.
8. Inkjet printing will seep into the porous surface of the tiles. It will reach both the hills and valleys of the flat tile blank. Other technologies, such as print-and-cut vinyl, will only float above the uneven surface of the tile blank.
The UV Inkjet Tile-Printing Option
UV inkjet printing adds one other benefit to the process. Unlike conventional custom printing inks (including inkjet printing inks), in which ink dries through evaporation or oxidation (often using heat), UV inkjet inks “cure” instantly when exposed to UV light. This means they will sit up on the surface of both porous and non-porous surfaces. This makes them more vibrant. They can also be applied in thicker layers than conventional inks.
The Takeaway
I would still suggest the following if you want to print on tiles:
1. Research the processes I’ve described. There’s a wealth of information online.
2. Contact flooring and/or tile stores. Ask about all of the available options for tile decoration.
3. Especially ask about the durability of the custom printing processes. Will printing on the pre-fired tile blocks be adequate, or will you need to decorate the tiles with heat resistant inks that will withstand the high temperature of the firing kiln?
4. Will you need some kind of protective coating over the printed image on the tiles?
5. Tell the tile printers how you will use the tiles. Will they need to tolerate foot traffic, or will they be used on the walls? Will they need to withstand moisture (as in a shower)?
No one will understand the benefits, limitations, costs, and uses of printed tiles better than tile shops that focus exclusively on this arena of home décor.
[Steven Waxman is a printing consultant. He teaches corporations how to save money buying printing, brokers printing services, and teaches prepress techniques. Steven has been in the printing industry for thirty-three years working as a writer, editor, print buyer, photographer, graphic designer, art director, and production manager.]