In the sunlight, the bright and colors of sublimation ink will occure varying degrees of change, absolute lightfastness ink color is rare. In strong sunlight effect, most of the ink colors will produce different degrees of change. This change can be divided into two types.

The first one is fading, under the influence of sunlight ultraviolet light, the ink has poor light and lost its bright color, the color becomes lighter, especially in light color ink, in four-color registering printing, yellow and red colors fade faster than blue and molv.

The second is the discolor, under the action of daylight, color change was darker, and the color has changed, this variation is considered as discolor.

Fading phenomenon is mainly due to the pigment itself lightfastness, the main factors that determine the light fastness of printing inks is pigment properties, followed by the connection material lightfastness properties. Processing technology will also affect the light fastness of ink colors.