Dye sublimation t-shirt printing is a digital process where ink is first printed onto sublimation transfer paper which is then heat pressed onto a synthetic garment under great pressure and heat. The dye sublimation ink vaporises and penetrates into synthetic garment (usually polyester). Upon cooling the dye particles are trapped in the garment which results in a colourful printed product of great durability and soft hand - you cannot feel the ink. A good short video illustrating this process is provided by Conde.
1. Use CMYK colour space. Sublimation t-shirt printing is a digital process and most commercial sublimation t-shirt printers, including ours, utilise only 4 colours in the ink set, namely CMYK (cyan, magenta, yellow and black) so only submit artwork in the cmyk colour space if you want the final result to approximate what you see on your monitor.
If you send Adobe RGB artwork, we can still print it, but the colours will vary if the colours you have used are out of gamut. The Abobe RGB colour space has much more colours than the CMYK colour space.
2. Keep Raster artwork between 150dpi and 300dpi. Any higher will just increase file size and not result in a higher quality print on the t-shirt. During the transferring process, the ink vaporises and condenses back. This disperses the dots printed so we do not require any higher resolution. Even 72 dpi is sufficient for most jobs provided the artwork is sharp.
3. Keep text in vector form outlined. This will result in a sharper print for small text and keep file sizes smaller. Rasterising text will just degrade the final result, plus rasterising also increases the file size. Remember to outline the fonts in Illustrator or curves in Corel.
4. Other considerations. Provide a mock up if you have an unusual position for your artwork. A picture is worth a thousand words. Please note that the colours printed onto the t-shirt will be close but not exact. We do not provide a PMS colour matching guarantee for sublimated printed t-shirts. The colour will vary according to the garment material, the pressure of the heat press and the temperature of the heat press. There are simply too many variables to account for. Of course if it is a large project, we can print samples for inspection and colour proofing. We need to print swatches with various colour mixes for the customer to choose from. For a one off t-shirt it is not economically feasible.