The colour of magic: Thermochromic Lush Spa vouchers

Pick up a spa treatment voucher and you’ll notice something special: a fantasia of tiny liquid crystals that react to the heat of your skin and blossom into stunning colour. 

This magical effect is down to the use of a design incorporating thermochromic ink: a material that reacts to changes in temperature to produce vivid patterns which then fade as the paper cools. See this technicolour wizardry first hand, pick up a spa treatment in store or choose from a selection of 11 spa treatments online.

Fairytale-esque it may be, but thermochromic ink developer Mike Parsley PhD assures there’s science behind the magic. As director of research at LCR Hallcrest LTD, a family-owned company pioneering temperature sensitive, colour-changing graphic technology, he’s dedicated his career to researching liquid crystal materials and spends his days concocting strange and wonderful materials in his lab just outside Poole, Dorset.

So just what is thermochromic ink and how does it work? It’s a difficult process to put into layman’s terms, as Mike explains: “The pigment is made up of an oily mixture of organic chemicals which forms a liquid crystal mixture. This reacts to changes in temperature by changing colour. For the best results, the inks need to be freshly made and printed in a well-controlled environment under strict protocols.”