Tile Files: Advancements in digital printing – April 2024

By Ryan Fasan

The first quarter of 2024 has come to a close, which means we’ve returned from Valencia, Spain and the 40-year-old international fair Cevisama, where Spanish manufacturers presented their latest innovations. The fair holds the honor of kicking off the year’s novelties, setting the tone for ceramic product development for the coming year. From a macro perspective, one key component that has made its mark on emerging ceramic collections and trends is the advancements in digital decoration.

A BRIEF HISTORY OF DIGITAL PRINTING
The leap from screen-printing-even the most advanced version featuring multiple rotating drum printheads-has been exponential. Digital application means faster prototyping, cost-effective iterations and smaller, more agile production runs, all while providing an exponentially broader array of variation.

The first digital (inkjet printing) machines were introduced by the Spanish company KeraJet at the same fair 23 years ago, in the dawning days of the new millennium. These early machines operated identically to the inkjet printers in homes and offices: the printheads featured four color-specific channels dropping a variation on CMYK inks. The early inks were solvent-based suspensions of fine-particulate, natural mineral oxides overlaid to create a wide spectrum of colors and tones. After nearly a quarter century of development, inkjets are now equipped with 12 channels, employing only water-based inks, and achieve aesthetics that reach far beyond the visual spectrum.

NEW DIGITAL PRINTING TECHNIQUES
Let’s take a deep dive into digital capabilities broadly adopted by leading Tile of Spain manufacturers in 2024. The four main categories of digital augmentations being applied in this year’s novelty collections are color, structure, finish and specialty.

COLOR: Inks in ceramics are employed just like acrylic inks in art, useful for their saturation of tone while offering transparency until layered multiple times. With the expansion of allowable channels, the array of achievable colors is exponentially better in modern inkjet programs. Most manufacturers have added a minimum of two colors to the classic CMYK palette, with many opting for the addition of true midtone neutrals of grey and white inks. These tones are especially important for manufacturers focused on stone reproductions, allowing them to apply white veins in marbles and achieve inviting grey tones that are easier to keep clear of the dreaded green-filtered grey. Some specialty Spanish manufacturers are even utilizing the full 12 channels of color to further enhance their capabilities to achieve more saturation and cleaner, mid-spectrum hues.

The advent of acrylic inks was a huge health and safety gain for factory workers, while at the same time reducing hazardous waste for the environment. The runoff from the glazing line can be filtered onsite, with the water reused, while recovered solids, being natural minerals, are reintroduced when refining ceramic material for the body of the tile.

This year marked a turning point in digital application of color at the fair, with one Spanish manufacturer, Realonda, achieving digital application of true mineral glaze in production volume settings.

The difference between a glaze and an ink is the incorporation of silicates (frit or pre-fired glass particulates with known sintering properties) to the suspension of mineral oxides. Previously, the particulate size of the silicates was too large for them to be reliably applied through the inkjet printheads. The digital application of glaze has been something desired by the industry due to the depth and saturation of tone unique to a glaze versus an ink. Furthermore, glazes offer a multitude of finishes that impact the reflectivity of the surface and therefore the perception of depth and colorfastness.

The ability to modulate these attributes in multiple ways and provide variegated surfaces is another catalyst for the entire product category. Realonda was justifiably awarded the coveted Alfa De Oro grand prize for innovation and design at the fair this year.

STRUCTURE: Gone are the days when a tile’s surface texture is determined by the mold used to press the tile into shape. Many modern Spanish manufacturers have transitioned away from multiple mold structures for their catalogue in favor of digital manipulation of the surface. The ability to add and remove volume by +/- 1mm creates a broad range of texture that can be applied to a tile’s surface after the body is pressed. This change has a positive effect on both production efficiency and aesthetic appeal, each working as a force multiplier on the other. The presses at the start of a production line drive the speed of the rest of the processes that follow. The less those presses need changing when switching from model to model, the faster and more cost-effective production becomes.

For the end user, this means better aesthetics at lower cost. Furthering that agenda, the digital application of structure means there is much greater variance in surface texture than possible with physical molds. For example, the average 24”x48” production mold features two cavities, meaning most of these collections feature two, four or, at most, six different textures, depending on how many presses are feeding the same production line, regardless of how varied the graphics are. Digital graphics files for the same size tile often feature 16 to 32 unique graphics, and with this innovation, those visual graphics also include topographical structures.

Digitally applied texture has another benefit other than broader variation. For the first time in ceramic production, a visual graphic can be directly applied “in-register,” or perfectly aligned with graphical cues. This means if the shadow of a wood’s grain or a marble’s vein is printed, the topography of that physical attribute is actually there, because that structure has been printed too.

FINISH: In modern production, it has never been possible to create a variegated finish on a tile’s surface-if a tile is matte, it’s matte all over, and the same is true for glossy. This is because glaze had to be applied in a homogeneous layer, usually by waterfall or spray. Digital effects changed that equation with the ability to print a targeted matte or glossy effect on certain areas of a tile’s surface. This capability is especially important for multimedia surfaces like terrazzo or vintage patina. Much like digital structure, these variations in finish are applied perfectly aligned with visual cues, making it possible to create truly natural spontaneity with unbelievable realism.

The ability to add glossy, matte and even refractive inks over surface graphics creates deeply nuanced surfaces, but the addition of true ceramic glazes to this mix will create another explosion of design potential for product development in years to come. The saturation and range of effects available with traditional glaze compared to inks are so much broader that we’ve barely even scratched the surface.

SPECIALTY: This digital printing method is the most commonly employed among ceramic manufacturing and is often used to enhance one or more of the preceding techniques. This type of digital augmentation is done by printing a latex adhesive on the surface of a tile, then covering the surface with fine silicate material. The silicates adhere to the acrylic and the remainder is blown off, to be used again on the next tile. In the kiln, the adhesive, along with any organic impurities, is burned off, leaving behind only the silicates, which sinter in place, creating a visual effect full of volume and texture. Depending on the type of silicates or even pure mineral metallics used, this process can be applied to both full-production field tiles or third-fire decorative pieces.

GOING FORWARD AND LOOKING BACK
The end results at this year’s Cevisama fair were truly mind-blowing. No longer is it the case that you can touch a tile’s surface and tell if it is ceramic imitating stone or wood. Even touching it, the structure is so varied and cohesively aligned with the visuals, it’s nearly impossible to tell the difference.

What I love about this new era of digital augmentation is that it’s not only breathing new life into ceramic’s ability to mimic alternative materials, but it’s also creating new possibilities to revive classic artisanal ceramics and glaze effects in a modern way at scale. That’s truly one of the most amazing things about the ceramic industry’s commitment to innovation-with every step forward, our ability to look back is improved. In ceramics, that means the ability to look back to ceramic artisans all the way from ancient Egypt to the modern day. With over three millennia of history and all the natural world to draw upon for inspiration, I can’t wait to see where we go next.

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