One of the best ways to insure a proper cure is called the stretch test. Since your white image will be a little thicker, this test is easy to read the results. After your shirt is cured, simply take a small section of your design and stretch it slightly between your fingers. If the design sticks together like plastic and stretches well, then it is cured and you can continue with those curing parameters. However, if the ink cracks or breaks apart, this means the base of the ink is not cured properly and you need to increase your curing time for the shirt.