Isabella Whitworth

probably more than natural and synthetic dyes, wax, resists, and history


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Tyrian Treasure: Part 2

woodbedford

Colophon from after 1850

Part One of this research story can be found in the previous blog, or just click here

The Bedford family of Leeds The Bedford family first started manufacturing orchil, a purple dye made from varieties of lichen, in around 1820. Orchil-making was a skilful process relying on fermentation, and dye vats could be expensively spoiled through inattention or inexperience.

Printed matter from early days of manufacturing. The name ‘Wood’ was retained after the death of Edward Wood, a sales partner from around 1850

Three successive generations of enterprising Bedfords steered the expanding manufacturing company into the 20th century, with achievements stemming from knowledge of new research and techniques, coupled with their inventive outlook. This period saw them incorporate synthetic dyes into their manufacturing, but their use of natural products for tanning and dyeing continued into the mid 20th century. The company changed names several times, but there was never a takeover. As ‘Yorkshire Chemicals’ the business finally folded in the early 2000s: by then there were no Bedfords in the company.

Charles Samuel Bedford (1865 – 1945) In 1880 – 81, Charles Samuel Bedford, grandson of founder James Bedford, attended the Yorkshire College to study chemistry. There was one other student: Arthur George Perkin, the second son of Sir William Henry Perkin whose 1865 discovery of a synthesised purple dye known as mauveine had revolutionised the dye and chemical industry. The meeting of these two young students developed to a lifelong connection when Arthur married Charles’ sister Annie. Arthur and Annie spent their lives in Leeds where Arthur worked at what became the University of Leeds. Strong social ties existed between both families.

Connections Family, scientific, and working connections of the Bedfords may explain why samples of genuine Tyrian Purple arrived in the archive. There was no commercial or industrial potential in shellfish dye so one can assume there was a purely academic interest in dyeing and retaining them.

What did the dyer of the Tyrian Purple need to know? Zvi’s photomicrographic images of the purple threads confirmed that the samples were evenly and homogeneously dyed, meaning that they were dyed, not smeared by direct application. Therefore, two key pieces of knowledge had to be in place to vat dye the cotton threads. The dyer needed to know that the shellfish pigment was an indigoid molecule, and that a reduction vat was required.

Knowledge of the hydrosulphite reduction vat was first presented in 1873 by Schützenberger and Lalande. Paul Friedländer’s work in 1909 Vienna determined that the main component of purple pigment from shellfish was an indigoid, namely dibromoindigo.

Scientific connections to the Bedfords were strong, coming from the wider Perkin family, and the Yorkshire College (later the University of Leeds) where Arthur worked. Latest research would have been quickly accessible.

tyrian

The envelope containing the two small skeins of shellfish dyed cotton: labelled in Charles Bedford’s handwriting

Dating the dyeing and the identity of the dyer The relevant part of the Leeds archive was assembled from around 1914. By considering the timeline, we arrived at a possible dyeing date of 1910 – 1913. The identity of the dyer remains unknown since no explanatory notes have been found, but the writing on the envelope containing the threads is that of Charles S. Bedford. So it’s quite possible he dyed it himself, had it dyed by a colleague well-versed in the chemistry of the time, or it was given to him by someone whose work he trusted. In Zvi’s words, this century-old Tyrian Purple sample is the most modern historic sample yet found: a true historic treasure.

Tyrian Purple, known as the ‘Purple of the Ancients’ was a well-discussed subject and appears in 19th century  literature associated, as ever, with wealth and status. The Bedford and Perkin families already represented two historic purples – orchil and mauveine – and one can imagine their curiosity about the dye chemistry of this exotic third.


 

demolition

Demolition site, Yorkshire Chemicals, Kirkstall Road, Leeds, 2008

The demise of Yorkshire Chemicals The Bedford family’s original business changed names several times over its lifetime, but there was never a takeover. It went into receivership in around 2004 styled as Yorkshire Chemicals. The factory on Kirkstall Road, first occupied by the Bedfords in 1850, was abandoned. I visited the demolition site in 2008 and felt unexpectedly emotional. Rising smoke, derelict buildings and heaps of twisted metal seemed the only legacy of a proud family’s early endeavours.

The Phoenix  But there is now an upside. The envelope of purple threads falling from hinges of an upturned rusty trunk has restored to us genuine samples of fabled Tyrian Purple. They are the first ‘modern’ dyeings known since  the 15th century, which illustrate scientific connections of the time as well as the curiosity, inventiveness, and the achievements of a Leeds family. To use Zvi’s words once more, the samples are like a ‘Phoenician rising from the rubble’, serving as a testament to past working and family lives of the Bedfords – and so many like them. They are, quite simply, Tyrian Treasure.

If you are interested in knowing more about any aspect of this research please write to me via the blog contact page.


Thanks 

Many thanks to colleague and friend Zvi Koren for his knowledge, his diligence and his support, and for his comments and additions to this pair of blogs. And for not forgetting to see the punny side of things.


Links and bibliography

Whitworth and Koren paper published in Ambix. Available from Taylor & Francis Online here.

Ancient shellfish used for purple dye vanishes from eastern Med  Guardian article , December 5th 2016


Related posts  on this blog

Testing Times 1 & 2

Getting to Blue

A Purple Pursuit

French Connections

Reasons to be Stressful

Talking Orchil

Dyes, History, and a Chilly Trip to Yorkshire


Inge Boesken Kanold artist researching and working with shellfish pigment

The Edelstein Center for the Analysis of Ancient Artifacts


John Edmonds’ book: Tyrian or Imperial Purple Dye: The Mystery of Imperial Purple Dye, Historic Dye series no. 7, Little Chalfont, 2000. Published by the author.


Smearing process of dyeing

 

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Tyrian Treasure: Part One

 

writtentyreThe Guardian: Monday 5th December 2016.

‘The shellfish that was one of the main sources of Tyrian purple – one of the most storied and valuable trading products in the ancient world – has disappeared from the eastern Mediterranean coast, amid warnings of an ongoing multi-species collapse blamed on global rises in sea temperatures.’

Historical cessation of shellfish dyeing The word ‘Tyrian’ derives from the city of Tyre on the north African coast, an area long associated with the Phoenicians and the shellfish dyeing industry. Tyrian Purple has already ‘disappeared’ once. Although an article linked from the Guardian states ‘snail-fueled purple persisted until chemists learned to make synthetic dyes,’ this is quite untrue.

It’s well known (in the dye world, at least) that shellfish dyeing largely ceased around the time of the Fall of Constantinople in 1453, after which the last dyers seemed to have disappeared. And in the eastern Mediterranean, purple dyeing ceased almost a millennium earlier as a result of the Arab conquest at the beginning of the 7th century.  Analysis of historic textiles continues to confirm this. The biochemical method of shellfish dyeing was complex, relying on processes which were not understood chemically, and were probably only passed down within families. Basically, when the dyers ‘disappeared’ they took the method with them. Any contemporaneous written records of the dye process are incomplete or ambiguous, and cannot be used to make a vat.

Recovery of the dyeing method Shellfish pigment must first be made soluble, (as with any dye), and this only occurs in alkaline conditions of around pH 8 and higher. An additional requirement for dissolution of the pigment is that it must undergo ‘reduction’. In reduction the pigment’s molecules are converted to a slightly altered, but more soluble, molecular structure. This reduction process is achieved by removing oxygen from the pigment molecules, or by adding hydrogen to them.  The vat turns a yellowy colour and fibre, threads or fabric are introduced. Colour will return to dyed items as they re-oxygenate on removal into the air. Readers who are indigo dyers will be familiar with this process.

The lost dyeing method Until the painstaking work in the 1990s of a retired engineer, the late John Edmonds, the exact method for creating a true shellfish purple reduction vat was lost. (Note that a reduction vat is entirely different from a direct application process performed by smearing the pre-pigment secretions).  Edmonds used his knowledge of woad fermentation to recreate the ancient shellfish dye method. He knew, from the early 20th century work of Paul Friedländer, that shellfish dye was an indigoid and would need a reduction process to work.  Edmonds used shellfish pigment extract for colour, and the rotting flesh of tinned cockles to start the required fermentation.  In subsequent years, chemist Zvi Koren (more about Zvi later) and artist Inge Boesken-Kanold separately explored and perfected more authentic historical procedures for dyeing and painting using shellfish purple.

The purple threads The earliest known historically accurate shellfish dyeings since the 15th century were, until recently, the initial samples produced by Edmonds. But in 2008 I discovered a small envelope containing purple cotton threads in a nineteenth / early twentieth century archive. They were labelled in as having been dyed with ‘the bodies of shellfish’. Could they be genuine?

dyedwith

bigtyre

Zvi Koren In 2011 I wandered around an exhibition in the company of Zvi Koren. Zvi is an internationally known and respected authority on shellfish purple and his lively presentations on the subject make him a unique and entertaining conference speaker. He showed interest in my presentations on orchil research, and we discovered a mutual obsession for appallingly groanworthy puns.

I tentatively mentioned the envelope of shellfish dyed threads I had found.  Zvi was clearly sceptical, as rightly befitted an analytical chemist, and was fairly certain the threads would be fake. He told me that only a scientific analysis, rather than visual inspection, would prove or disprove the claim. In his work, Zvi has analysed archaeological dyeings previously claimed by analysts to be shellfish dyed. Zvi’s precise analyses on these same artefacts showed that the ‘real purple’ was in fact an overdye produced from madder and indigo. He reminded me that prior to the work of Edmonds and others I’d have to go back nearly 600 years to find a true dyeing supported by chemical analysis. Paul Friedländer, who first identified the chemistry of shellfish purple in 1909, left no known samples.  But Zvi’s a good sport and was clearly intrigued. He suggested I send a small sample of the threads to him for analysis at the Edelstein Center for the Analysis of Ancient Artifacts, in Israel. So I did.

The research Zvi has described his astonishment when his analysis found the dyeing to be genuine shellfish purple, and he suggested we write a paper together. The work we undertook mapped a possible scenario for how the dyeing came about, why, and at what date. It involved parallel investigations based on Zvi’s scientific analysis of the threads through photomicrographic images and instrumental chromatography. We also studied classical and biblical texts; 19th century literature; the history of science and scientific connections; and the remarkable Bedford family of Leeds.  Zvi was extremely patient with my lack of chemical knowledge and I continue to be grateful for his clear explanations, and the general good humour which illuminated the science I frequently failed to grasp.

Significance of our research So is this a big deal? We definitely think so. It’s huge!  Firstly, before the Tyrian Purple dyed threads I found, no other dyeings have been confirmed since around the 15th century. That’s of considerable interest to researchers. Additionally, their very existence superbly illustrates the activities, interests and connections of an industrious Leeds family in the late 19th and early 20th century. More of that in Part Two – which will follow in the next fortnight.

If you are interested in knowing more about any aspect of this research please contact me through the blog. 


Thanks Many thanks to colleague and friend Zvi Koren for his knowledge, diligence and support, and for his comments and additions to this and the following blog. And not forgetting the puns.


Links and bibliography

Whitworth and Koren paper published in Ambix. Available from Taylor & Francis Online here.

Ancient shellfish used for purple dye vanishes from eastern Med  Guardian article , December 5th 2016


Related posts  on this blog

Testing Times 1 & 2

Getting to Blue

A Purple Pursuit

French Connections

Reasons to be Stressful

Talking Orchil

Dyes, History, and a Chilly Trip to Yorkshire


Inge Boesken Kanold artist researching and working with shellfish pigment

The Edelstein Center for the Analysis of Ancient Artifacts


John Edmonds’ book: Tyrian or Imperial Purple Dye: The Mystery of Imperial Purple Dye, Historic Dye series no. 7, Little Chalfont, 2000. Published by the author.


Smearing process of dyeing