One Ink for All? Exploring Pigment in Textile Printing

Digital textile printing faces complexity due to diverse substrates requiring specific inks. The industry seeks a universal ink, with pigment ink showing potential. While traditionally for natural fibres, advancements aim to broaden its application, simplify processes by reducing pre/post-treatment, and improve sustainability, though challenges like hand feel on garments remain.

One of the difficulties in discussing digital printing to textiles is that the term ‘textiles’ is just too broad as it can cover several distinctly different substrates. For each of the different class of textiles, there is a corresponding type of ink that has been formulated to bond with the fibres of that fabric. So, for example, polyester is best printed with dye sublimation inks, while acid inks give the best results for silks.

This means that anyone printing large volumes of textiles will have to invest in multiple printers in order to have a solution available for any of the major fabrics, be that cotton, polyester, silk, wool and so on. Most vendors have responded by reformulating their inksets so that they can cope with a broader range of fabrics, including the many blended materials that exist, such as polycotton, which mixes polyester and cotton. But the holy grail still remains the idea of a single inkset that can print to any textile, and also do away with the need for both pretreatment and post-processing. And over the last five years or so there has been much discussion around whether or not textile pigment inks could be developed to do just that.

There’s nothing new about textile pigment ink, which has been used for printing to natural fibres such as cotton for many years. But of all the different classes of textile ink, this is the easiest to evolve into a universal ink. Actually, pigment ink is a somewhat misleading term since most inks do use pigment particles as their colourants. So really it’s the other components that distinguish one ink type from another. In most textile pigment ink, the individual coloured particles are encapsulated in a synthetic resin along with binding agents and then suspended in an aqueous carrier liquid. Once the ink has been jetted, heat is applied to evaporate the water content and melt the resin, which bonds the pigment to the material surface.

It is still necessary to apply some form of pre-treatment or primer to the substrate. This gives the drops of ink a key to hold onto the surface and to limit dot gain from spreading, before the final curing stage. One of the problems with earlier textile pigment inks is that they struggled to cope with multiple wash cycles with the colours being prone to fading at a much faster rate than was acceptable to consumers. Improvements in the quality of the pretreatment has helped with the overall wash fastness so that the final graphic should survive many wash cycles without losing its colour.

EFI Reggiani has developed a range of textile pigment inks for printers such as this EcoTerra Gold.©Nessan Cleary

One of the major advantage of pigment inks is the possibility of eliminating the need for post-printing stages such as washing and ironing. There are a number of advantages to this. For a start, it saves time, which is particularly important in any kind of on-demand environment. In addition, extra processes require the staff to carry them out, and that adds to the labour cost. That said, saving time and labour is less of a problem in emerging nations, including across Asia where garment production is highest.

Nonetheless, eliminating the finishing steps still makes sense from a sustainability viewpoint. Digitally-printed textiles in general are more environmentally-friendly than conventional methods because they use less water, and there is less chance of contamination of waterways from run-off. However, some inkjet inks still require a lot of water for washing and steaming to fully cure the ink and ensure that the colourant has bonded fully with the fibres. That also means more drying, and sometimes ironing, which in turn requires more energy. But because most pigment inks form a chemical bond with the textile surface, there’s less need for further washing and drying stages, so less water and energy is consumed in production. This also cuts the cost of production. That said, some pigment inks require a relatively high temperature to cure the ink, which consumes a lot of energy and can damage some fabrics.

Also, because the ink sits on the surface of the textile, it does change the handfeel of that fabric, which is a fundamental issue for most garment production. In contrast, most textile inks penetrate beneath the surface and bond with the fibres, so that the fabric retains its original surface hand feel.

This has meant that some pigment ink is more suitable for furnishings than for garments, where consumers will accept a rougher feel to the final material. That said, the latest generation of textile pigment ink is starting to overcome this issue. This is mainly down to using better milling technology to produce smaller-sized particles, coupled with improvements in the binders used, alongside the use of softening agents in the ink. The smaller particles are easier to jet, so there are less problems with blocked nozzles on the printheads. More importantly, the smaller particles also give a more natural feel to the fabric surface, allowing the material’s natural feel to come through the ink.

Otherwise, the biggest challenge still remains the range of materials that most pigment inks will print to. This class of ink should print to cellulose fibres, meaning fibres that have come from a plant base, such as cotton or linen. Some of these inks can also cope with regenerated cellulose materials, such as viscose, also known as rayon. Some of the available pigment inks will print to materials made with synthetic fibres, such as polyester or nylon, as well as blends between the two types of fibre, such as polycotton.

Some vendors will also claim that their pigment inks can print to those fibres that have come from an animal base, such as wool or silk. There may be an argument that using pigment inks to eliminate the post-print processing can lower the costs, particularly with synthetic materials like acrylic wool.

However, the best results for these higher quality fabrics still come from using dye-based inks, such as reactive for wool or acid for silk, especially for high value applications such as silk or merino wool scarves. But new inksets are being developed all the time that promise to overcome some of these limitations. The upcoming Fespa Global exhibition in Berlin in May offers a good chance to see some of these solutions in person.

Discover the latest innovations in inks and textile printing at FESPA Global Print Expo 2025, Europe's leading print and signage exhibition taking place from 6 - 9 May at Messe Berlin, Germany. It will showcase the most innovative products, visionary concepts, and latest developments in the future of print. Register to visit here.