Dye-Sublimation Printing

What is Dye-Sublimation Printing?

When asked this very question over the years, I’ve often answered by suggesting the print process is an almost print / heat press. Though this was largely without much knowledge or understanding, I’d say I answered pretty well, all things considered. Effectively the printer uses heat to transfer dye from its media, to the substrate (paper in my instance).

In an unhelpful way, the name dye-sublimation also gives off a false pretence. The origin of the ‘sublimation’ name comes from the early days of printing, where it was thought the dye would transition between the solid and gas states, without actually going through a liquid stage. This was later discovered to be incorrect, but the name ‘dye diffusion’ never really caught on. Though the original use was for creating prepress proof images, today dye-sub technology still thrives in ID card printing as well as the obvious dedicated photo printers.

Process…

The printing process involves a dye-sublimation media pack, and within this pack there is a paper roll and a polyester ribbon. The polyester ribbon contains 4 separate panels, 3 of colours (yellow, red and blue), and 1 final laminate layer. Each panel also has to match the size of the medium it’s being printed on, in my example that’s an 8x6” (20x15cm) paper roll.

During the printing cycle, the printer rollers will move the paper and one of the coloured panels together under the thermal printing head. Here, tiny heating elements on the head change temperature rapidly, in order to lay the dye onto the paper, via diffusion. The temperature of these elements depends entirely on how much of a certain coloured dye, is required for the image. 

After the printer finishes printing the medium in one colour, it advances the ribbon to the next colour panel and even partially ejects the paper from the printer to prepare for the next cycle (colour). In the example of my printer, this process is repeated 4 times; the first 3 lay the colours onto the paper, in order to form the complete image, before the final laminate layer provides both UV and moisture protection to the final product.

Print Speeds…

As dye-sublimation printers utilise heat, to transfer dye onto the print media, the printing speed is limited by the speed at which the elements on the thermal head can change temperature. Heating the elements is easy via a strong electric current, however cooling the elements down (when changing from a darker to a lighter colour) is much more of a challenge. This is often combat by either having a fan attached to the print head, or, through the use of multiple print heads; allowing one to cool down whilst the other is in use.

Your typical consumer dye-sub printer would print a 6x4” (15x10cm) image in the realms of 60-90 seconds. Whereas a more heavy duty dye-sub printer can print much faster. My Mitsubishi CP-D70DW can print the same 6x4” photo in just outside of 8 seconds, and my most commonly used image size (a 8x6” print) in under 15 seconds. In all cases, a dye-sub print will always emerge from the printer completely dry, and as such, the fear of leaving fingers prints all over your images, will be a thing of the past.