The dye sublimation process first made an appearance around the late 1950s in France.
There were no wide format inkjet colour printers at that time, so the dyes were imprinted onto ribbons or sheets that, when thermally activated, released themselves where the image or pattern was, turned into a gas, bonded into (not onto) the substrate and delivered vibrant colours that became part of the fabric, plastic or even metal that they are sublimated into.
The majority use became textiles although dye-sub (more correctly dye-diffusion) photographic printers were popular for a while, using continuous rolls of transfer ribbon alternating CMY-CMY for the thermal heads to deposit the colours into the substrate. They are still around in niche applications such as event and kiosk use.
When wide format inkjet came along, it didn’t take long before the sublimation fraternity saw the potential for much wider output, using special inks and a transfer paper that could hold plenty of ink but release it into the material when under heat and pressure. Neenah Coldenhove’s JetCol pioneered this from the 1990s.
The colour range was increased with special blue, orange, violet and even fluorescent pink and yellow for snazzy sportswear. Sportswear is a major market for dye-sub as the garments are usually polyester. Fespa has introduced a dedicated Sportswear sector for its 2020 Madrid show.
Dye-sub has many fantastic advantages that direct-to methods can’t yet match but it also has a couple of disadvantages. The textile needs a high polyester or other polymer content such as Lycra because, when heated, the pores open up, enabling the gaseous dyes to enter and then become entrapped within when they cool. With cotton, there are no synthetic filaments to open up so direct printing to the surface is the only option apart from screen printing; still an excellent way of decorating textiles. Another disadvantage is absence of white ink. When printing on dark coloured material, colours will appear dull and lack contrast.
However, dye sub still rules the roost when it comes to colour quality, feel, durability and ability to print on non-textile polyester-treated products such as plaques, awards, promotional products, photo panels, memorial products, signage, mugs, thongs, flags, tiles, phone covers, laptop sleeves, stadium seats, acrylics, wetsuit material, skateboards, surfboards, home décor, and soft signage.
The success of dye sub is reflected in the Smithers Pira 2019 future of dye sublimation printing report which forecasts an 18.4 per cent annual year-on-year growth rate up to 2023. This would take the sector to over USD$5bn in value. No wonder HP has joined Epson, Mimaki, Roland DG and Mutoh in making dye-sub printers.
At Fespa, HP showed three models of its new Stich S series of dye-sub printers; two at 1.625m and one at 3.2m. New is the in-built spectrophotometry for fast colour matching and calibration. When sublimating, the challenge for colour is that the image is printed in reverse on a sublimation paper, which then looks dull until transferred to the textile in a heat press or rotary calendar.
Colour profiling must interpret the final printed result from the transfer paper image. In-built colour management speeds this up considerably. The Stitch S series is also capable of direct-to-fabric printing but remains a CMYK printer.
The next stage of dye sublimation is to enable direct inkjetting of special inks, which are then heat pressed and sublimated into the material without the use of transfer paper. For now, the transfer paper method remains dominant for quality and reliability. The paper is specially engineered to release its dyes as gasses into the substrate but allow out-gassing through the back surface. It is not easy and some are better than others. Cockling is a common problem with the lighter transfer papers.
The results speak for themselves: dye sublimated/dispersed products using quality transfer paper, inks, and heat presses stand out for their brilliant colours and durability.
It is all part of the fabric of success.
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