Sublimation is a lot like cooking. I think of a heat press as a stove and imprintable substrates as all of the different types of foods that require their own unique preparation, cooking styles, cooking times, and even cool-down procedures. The best “cooks” often use a set of instructions as a starting recipe, observe and document their results carefully, and then possibly make subtle changes to the instructions to achieve optimum results in their own dye-sub kitchen. Once I determine what works best on my heat press, I tape it to my press for quick reference.
A great method to find a substrate’s ideal press time is to perform a “black test” by printing a solid black print (RGB of 0,0,0) and then pressing it onto the selected substrate. Black is the last color to sublimate, so if you get an awesome uniform black, you have it dialed in. If pressed too long, black typically starts to turn brown. If you get stuck, don’t continue to waste products: pick up the phone and call your supplier for help.
-David Gross, Condé