Any colour you like

Using a tabletop laser, University of Rochester optical scientists have turned pure aluminium, gold. And blue. And grey. And many other colours. And it works for every metal tested, including platinum, titanium, tungsten, silver, and gold.

Chunlei Guo, the researcher who a year ago used intense laser light to alter the properties of a variety of metals to render them pitch black, has pushed the same process. He now believes it is possible to alter the properties of any metal to turn it any colour - even multi-coloured iridescence like a butterfly's wings.

Since the process changes the intrinsic surface properties of the metal itself and is not just a coating, the colour won't fade or peel, said Guo, associate Prof of optics at the Institute of Optics at the University of Rochester.

He suggests the possibilities are endless - a cycle factory using a single laser to produce bicycles of different colours; etching a full-colour photograph of a family into the refrigerator door; or proposing with a gold engagement ring that matches your fiancée's blue eyes.