And dye hair they did. In fact, the anthocyanins from blackcurrant waste work just as well as the synthetic dyes they are replacing, according to Dr. Blackburn. But you can cast aside the notion that the finished product – available to buy this summer, through a University of Leeds spinout company, Keracol Limited under the brand Dr Craft – will leave your lengths like Charlie And The Chocolate Factory's Violet Beauregarde’s (bright blue and bright blue only). According to the experts, the patented hair dyeing technology not only serves up intense reds, purples and blues, but when combined with yellow, could provide a wider spectrum of hair colours, including browns. Impressively, tests showed that the colour stayed put for up to 12 washes, similar to DIY dyes we all know and love.