Direct-to-Card Printing Direct-to-card ID card printing, also known as dye-sublimation or dye-diffusion ID card printing is the most common method used to print images directly onto ID card surfaces. With direct-to-card printing the ID card printer transfers color directly to a blank ID card by heating a special ribbon beneath the thermal printhead. The heat from the printhead causes the ink in the ribbon to vaporize into a gas, which then diffuses into the surface of the ID card, where it solidifies, or sublimates, into a solid, resulting in a durable color pigmentation on the white surface of the ID card, that resists scratching and fading. Since the ID card printer can only lay down one color at a time, the dye-sublimation process is repeated for each YMCK panel until a complete, colored image is formed on the ID card. As a final step, the printer prints an overcoat (O) panel over the entire ID card surface, protecting the card from UV and physical damages. Certain brands of ID card printers can also print a secure watermark onto the surface of ID cards during this step in the ID card printing process.