<p>ThermoStar Photochromic inks change colour when exposed to ultraviolet light usually from the sun or a black light. The inks are effectively colourless indoors and turn into vibrant colour outdoors. When brought back inside, the inks become clear again. The inks become intensely coloured after only 15 seconds in direct sunshine and return to clear after about 5 minutes indoors.</p><p>These Inks can be featured in a variety of applications revealing that a product has been exposed to UV light, including high end promotional items, textiles, plastics and packaging.</p>