Oooh, look what's at the Beeb: Supermarket molluscs reveal Roman secret.
Posted on September 12, 2003 10:50 PM. Filed under: history & archaeology.The secret of imperial purple has been rediscovered.
A British amateur chemist has worked out how the ancient Romans dyed the togas of emperors this deep colour thanks to a bacterium found in cockles from the supermarket Tesco.
The hue had special significance as the colour of imperial power. Cleopatra also had the sails on her ship dyed the same colour.
The recipe for the dye had been kept a craft secret, even in ancient Egypt and Rome. There are few references to the dying process in the historical literature.
Modern chemistry can make every shade of every colour, but retired engineer John Edmonds is interested in how the ancients managed to make dyes from natural materials.
He explained to the British Association science festival in Salford, Greater Manchester, how he rediscovered the secret of imperial purple after studying the fermentation process of indigo pigments from the woad plant.
With help of researchers in Reading and from Israel he has been able to establish the vital role played by a bacterium in chemically reducing the ancient pigments so that they will dissolve in a dye solution. [continue]