A dye-sublimation printer  employs a printing process that uses heat to transfer dye onto many materials, including paper. Many consumer and professional dye-sublimation printers were designed and used for producing photographic prints. A dye-sublimation printer produces true continuous tones appearing much like a chemical photograph. The dyes diffuse a small amount before being absorbed by the paper. Consequently, prints are not razor-sharp. For photographs, this produces very natural prints, but for other uses (such as graphic design) this slight blurriness was a disadvantage.

 

Most dye-sublimation printers used four colours CMYK (Cyan, Magenta, Yellow and Black) sometimes the black was eliminated in favour of a clear over coating. This over coating was also stored on the ribbon and was effectively a thin layer which protected the print from discoloration, from UV light and the air. The most common process layed one colour at a time, the dye being stored on a polyester ribbon that had each colour on a separate panel. Each coloured panel was the size of the paper that was being printed on; for example, an A4 dye sub printer would have had four A4 panels.

 

During the printing cycle, the printer rollers would move the paper and one of the coloured panels together under a thermal printing head. Tiny heating elements on the head change temperature rapidly, laying different amounts of dye depending on the amount of heat applied. Some of the dye diffuses into the printing medium.

 

After the printer finished printing one colour, it would wind the ribbon on to the next colour panel and partially eject the paper from the printer to prepare for the next cycle. The entire process would be repeated four or five times in total: the first three lay the colours onto the medium to form the complete image; there may or may not then be a black thermal transfer process; while the last one lays the laminate over the top. This layer protected the dyes from UV light and moisture.

 

Traditionally, the advantage of dye-sublimation printing had been the fact that it was a continuous-tone technology, where each dot could be any colour. In contrast, inkjet printers could vary the location and size of ink droplets, a process called dithering, but each drop of ink was limited to the colours of the inks installed. In the early days of inkjet printing, the large droplets and low resolution made inkjet prints significantly inferior to dye-sublimation, but today's inkjet printers produce extremely high quality prints using microscopic droplets and supplementary ink colours, producing superior colour fidelity to the old dye-sublimation printers.

 

Previously, the use of dye-sub printing had been limited to industrial or high-end commercial printing, however, dye-sub photo printing became used in medical imaging, graphic arts proofing, security, and broadcast related applications.

 

Now days, it has become a much cheaper product to buy and run and subsequently has become extremely popular in event photography and photo booths or kiosks that require high speed, on-demand photographic style printing.