A heat press is required for sublimation transfers. Time and temperature may vary based on press and substrate the transfer is being applied to. Sublimation transfers for shirts must be applied to white or light colored shirts with a minimum 50% polyester. The higher the polyester count the more vibrant your images will be. The lower the polyester count the images will have a vintage look. Sublimation ink is transparent using the transfers on colored shirts will affect your final color of prints.