Acid inks
Acid inks are etched into fabrics to offer strong outdoor longevity, making them ideal for flags and banners. They are also used in swimwear.
An acid ink can be used on pretreated synthetic materials, such as nylon and spandex, as well as on pretreated natural fabrics like silk, wool, angora, alpaca and some types of leather. The same steaming and washing process used with reactive inks is required to finish fabrics printed using acid inks.
Textile pigment inks
Textile pigment inks offer excellent lightfastness and can be used on all fibres. This type of ink uses a heat fixation process and requires a resin-based carrier to bond it to the fabric. The inclusion of the resin removes pigments, resulting in less washable durability.
These inks are general-purpose formulations, more commonly used in offset and traditional analogue methods than in digital inkjet printing.
Solvent/eco-solvent inks
The most versatile inks are solvent-based or ‘eco-solvent’ variations. They are widely used for outdoor signage, durable graphics and specialty applications like transfer-based T-shirt images.
Fabrics used with these inks need a solvent-resistant coating or the oils can wick and negatively affect the base substrate. Post-print processing is not required, although some colours may appear less vibrant, requiring the addition of an overlaminate to make them ‘pop.’
Soft signage has become popular because it is lighter, more easily rolled and packaged and more durable than many rigid applications.
Latex inks
Relative newcomers to the digital textile printing industry, latex inks are water-based and can be printed onto the surfaces of coated or uncoated non-wearable fabrics, canvas or wallpaper, among other materials. They typically require a higher level of heat fixation than with eco-solvent inks, but their advantage over dye sublimation inks is they can be printed directly onto materials that cannot be post-processed at quite as high temperatures as those of a calender heat press without risking distortion or discolouration.
Compared to some other types of inks on fabrics, latex-based prints may be more subject to wrinkling and suffer from lower scratch resistance.
UV-curable inks
Many printers today use UV light to cure (‘set’) inks onto the surface of an uncoated substrate. These inks are compatible with most closed woven fabrics, such as canvas, but some may require the addition of a primer layer to keep the ink on the top surface of the substrate to ensure proper curing.
UV inks are widely used in flatbed printers to produce signage and graphics on rigid media and in roll-to-roll printers for vinyl and other flexible media. As such, they vary in terms of flexibility. Some are too brittle for use on fabrics, but others are sufficiently flexible for soft signage applications.
Solvent UV inks
As the term implies, solvent UV inks marry the best attributes of solvent-based and UV-curable inks. The solvent component is aggressive with the accepting layer of the media, fixing the pigment to the substrate, while the subsequent UV curing both contributes to the graphics’ durability and ensures vivid colours with a smooth, glossy finish. These types of inks are best-suited for tightly woven soft signage and interior décor applications.
