Supermarket molluscs reveal Roman secret

BBC News ^ | Friday, 12 September, 2003 | Kristine Krug

[presidio9]

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.

Green to purple

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.

The pigment for imperial purple was derived from Murex molluscs, a form of shellfish. So, Mr Edmunds reasoned that he could try to use the related common cockle.

He bought a jar of them from Tesco. "Having removed the vinegar, I placed several of the cockles with some of the purple pigment in a vat consisting of a 2 lb jam jar."

Modern jeans

The cockles are thought to harbour a bacterium that is crucial in reducing the dye. Wood ash was added to the vat to ensure the mixture did not turn acidic.

The mixture was then kept at 50 Celsius for about 10 days.

Wool dipped in the pigment turned green at first but, eventually, in contact with light, it turned purple.

The recreation of the old dying method might have implications for present-day practice.

Currently, tonnes of chemicals are needed to reduce the dye for denim blue jeans, resulting in large quantities of sulphur waste.

Mr Edmonds said: "University of Reading scientists are trying to understand how the bacterium reduces indigo in order to develop a clean biotechnology to replace the chemical process for indigo reduction in the future."

[Huck]

Well, it's good to know we finally got that straightened out.

[KantianBurke]

"Bwing me some moowusks!"

[GraniteStateConservative]

So, still no cure for cancer?

[ffusco]

Cancer isn't one disease it is a pathology of diseases.

[HighWheeler]

This guy should have filed a patent for the process. He is out Multi-Million$ thanks to yapping about it.

However, maybe he was smart enough to leave out a key element or step in the process for this interview.

[bvw]

Reducing the chemicals needed to produce dye-stock does reduce cancer. What is done is the chemical factories are being micro-sized into packetized-factories called bacteria. The toxic and mutagenic chemicals and by-products are all kept within the micro-packetized factory, and not only that the micro-factory is very effecient at using the minimal amounts needed and only when needed, usually turing the really bad bad toxins harmless in some side reaction that immediately follows a toxic step in the dye-producing process.

[LibWhacker]

A journey of a thousand miles begins with one step, Grasshopper. :-)

[general_re]

"Stwike him, centuwion, vewwy woughly!"

[LizardQueen]

He bought a jar of them from Tesco. "Having removed the vinegar, I placed several of the cockles with some of the purple pigment in a vat consisting of a 2 lb jam jar."

LOL...... I love backyard scientists like this!!

LQ

[70times7]

pweese wun yowr speew chekur. You shouwd have witten "wuffwee", wather than "woughly"

[CathyRyan]

ping (Sorry, do not know if you would be interested in this or not)

[norton]

Yeah,
But I bet it's heck on the ozone layer.

(wouldn't it be a hoot if it turns out the magic ingrediant was the vinegar?)

[GraniteStateConservative]

You have such a lovely sense of humor. You must be great at parties.

[Darksheare]

I try to stay away from parties.

Sulpher waste produced by reducing the dye used in blue jeans?
Wouldn't that be Hillary's domain?
And couldn't she use the sulpher?

[tet68]

"Ah, but what did the purple represent ?" asked Demeter, whose hair falls in golden tresses as only a goddesses does.

"I know , I know !", cried Persephone, "It represents the kykeon of Eleusis!"

At least it did for thousands of years.

Try some, you'll like it, and become epoptes
with the rest of us. :^)

[Squawk 8888]

We who are about to dye salute you!

<----- Running away

[ffusco]

Yeah, but sometimes I get too chatty. "The professor will now expound"

[El Gato]

This guy should have filed a patent for the process. He is out Multi-Million$ thanks to yapping about it.

Actually that would be multi-million "Pounds". But who's to say he didn't file a patent application. The article doesn't say that he did not. However I'm not sure one can patent a existing process, even though one long lost. He probably can, since he didn't get it from reading old documents, but rather "rediscovered" it.

[blam]

"ping (Sorry, do not know if you would be interested in this or not)"

Yes. I thought the Phoenicians controlled the colr purple for centuries. Also, there's a place in Turkey where the Romans mined 'purple' granite and it was against the law for anyone else to use the color purple.