Isabella Whitworth

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


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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


 


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Testing Times 1 & 2

Testing One

I have many friends who take an interest in my pots of goo and occasionally they send me things. One such friend returning from Essaouira sent me pigment she had been sold as ‘shellfish purple’. Historically, the Moroccan coast was an area much involved in the making of this fabled dye (also known as Imperial Purple and Tyrian Purple) but I expressed doubt that what she had sent was ‘the real thing’ because it is fabulously expensive to produce even a small quantity. Just 5 grams costs around £450.00. But I thought it would be fun to try dyeing with it.

grains

Green grains and finished colour on silk

I took advice from a specialist colleague, Professor Zvi Koren of the Edelstein Center for the Analysis of Ancient Artefacts (link below). He advised that shellfish pigment is not water-soluble, so that by adding just water I would not get a true solution: I’d get a reddish coloured mixture with the pigments dispersed but not dissolved. I added water and the grains went bright pink. Very bright indeed, as you can see below.

pH

The colour of the grains in solution: testing pH

reduced

Reduced liquid with lumps of dye matter

Following my colleague’s advice, I reduced grains in a hydrosulfite / dithionite bath in an alkaline solution, at about 60 C. The liquid went completely clear, with the dye matter gathered in lumps. This didn’t look right at all for shellfish purple, which should change to a greenish colour (as with indigo).  Nevertheless, I dipped silk into the clear mixture and it came out a bright pink – which does not wash out. So it’s certainly a dye, but certainly not shellfish purple.

Two other pointers to its not being shellfish purple: the Essaouira grains are green, and they shouldn’t be. There’s no snail pigment that colour, according to my colleague. It’s usually dark, blackish, brownish, purplish or violetish, but never green. And on top of that, the grains should have a yukky fishy smell. The Essaouira grains smelled vaguely of incense.

So this was a fascinating experiment, a story echoing many historical tales of dyes that were not as they claimed.

My thanks to Professor Zvi Koren of the Edelstein Center for the Analysis of Ancient Artifacts for his input and advice on testing the Essaouira grains.

Friends: please don’t stop sending me interesting things. But as an H&S caveat, pigments and grains bought in faraway places may be toxic or otherwise harmful so you need to be aware of handling and storing them. They are not necessarily what they say on the tin.

Testing the Other

At a recent course at West Dean my Old Geyser of a fabric steamer developed a problem. The thirty-year old steamer assembly consists of a standard water boiler (the sort to be found in every village hall), a custom-made stainless steel chamber, lid, and perforated base plate. Silks are rolled in paper and stacked upright inside the steel chamber. Water is heated in the boiler, the steam circulates and the combination of heat and damp sets the dyes. The water isn’t held at a constant boil but needs to come up to the boil – and hold it – every two or three minutes, for around two-and-a-half hours.

Only, at West Dean, it didn’t. The boil was less frequent than usual, and was held for shorter periods. I was concerned that dyes were insufficiently fixed and suspected a problem with the thermostat. (I should add that West Dean supply a professional Uhlig steamer, but I have always used mine, which holds more silk).

Back home, phone calls revealed that a new ‘simmerstat’ is what I required. But during the time since I bought the boiler, Brussels has dictated that EU citizens are insufficiently responsible to handle dangerous pieces of equipment that boil water. (Those in favour of Brexit might enjoy the link at the bottom of the page). A catering boiler will no longer come to a full, constant boil. My new simmerstat was fitted by the technical department, but the gaps between boils seemed longer than I remembered…. or was I just being twitchy?

I then discovered that a secondhand Uhlig steamer was on sale, owned by an ex-student. I couldn’t believe this piece of luck – and bought it. It is a solid, stable and well designed piece of equipment, although as with the West Dean one, it does not hold as much yardage as Old Geyser. In the Uhlig I tested several pieces of silk, including three blues which have a tendency to run if steamed sufficiently. No run-off.

runoff

Some runoff may be expected in initial rinses after steaming if heavily concentrated dye is used. Thereafter the water should run clear

samplessteam

Samples of identically dyed silks steamed in two steamers to compare colour and runoff

I tested identical blues in the mended Old Geyser. It now appears to be working well too – so I now have two working steamers. No recycling tip for Old Geyser: he threw a steamy party.

LINKS

Where to buy shellfish purple in 2016? Here

Brexit? Pulling the plug on high speed kettles here

The Edelstein Center for the Analysis of Ancient Artifacts here

 

 


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Getting to Blue

In my last blog A Purple Pursuit, I wrote about Browning’s Popularity, in which he referred to shellfish dye in a complex poem on inspiration, skill and genius. What I didn’t say, but others wisely pointed out, was the oddity of Browning referring to the dye as blue throughout the poem. Shellfish dye (from the ‘Tyrian shells’) is quite definitely purple and the colour, history and source of Imperial Purple were well known in Browning’s time. So, why blue?

Who has not heard how Tyrian shells
Enclosed the blue, that dye of dyes

Whereof one drop worked miracles,
And coloured like Astarte’s eyes
Raw silk the merchant sells?

I scratched around many sources but failed to find a historical reference, or image, defining Astarte’s eyes as blue. Maybe I have missed something. But the Resident Poetry Advisor says that Browning was more than capable of implying non-existent references, or even inventing them. This seems most perverse, but Browning was a poet and that’s the kind of thing poets do.

indigo

Author’s indigo-dyed wool yarn, using increasing vat strength

Putting Browning firmly aside, I happened across a reference to William Gladstone’s Studies on Homer and the Homeric Age. Gladstone (1809 – 1908) was a British Liberal politician, three times Prime Minister, living at a time when politicians digested more than soundbites.

Gladstone studied the Iliad page by page, and as he did so he recorded the occurrence of words for colour. What he noticed was rather remarkable. He came across much mention of black, some white, less red, very little yellow, tiny amounts of green…but no blue. Was Homer ‘colourblind’, or unable to perceive colours? Were all Greeks the same, and their perception of colours (and the words to describe them) inherited, building over several generations? It left me wondering whether Astarte’s eyes could have been blue if there wasn’t yet a word for it, which was a head-spinning prospect.

Lazarus Geiger (1829-1870), a philosopher and philologist, took Gladstone’s research further and studied other ancient texts (for instance, Icelandic sagas, Vedic literature, and the original Hebrew version of the Bible) finding that none of them contained a word for blue. Geiger concluded that across ancient cultures, words for colour developed in an oddly consistent order. Black was always first, followed by white, red, yellow, green. Blue came next, eventually.

If this intrigues you, I suggest you listen to the Radiolab broadcast linked below. It makes more sense of it than I can here, but still left me wondering what exactly was being said. One of the programme’s guests is linguist Guy Deutscher. Listen, particularly, to the account of his little daughter trying to name the colour of the sky.

buddhist_edited-1

Author’s watercolour from sketchbook, 1995, recording the many dyed colours and fading shades of Buddhist monks’ robes in Sikkim and North India

My head can’t get itself round the concept that without an object to attach it to, a colour didn’t ‘exist’ and didn’t acquire a name. But that’s partly what is being said and it leads me to dyeing, and the need to name colours. I was dyeing felt last week, trying to achieve a good range of reds. I used different amounts of mordant, varied the percentages of weld, cochineal and madder and overdyed in different sequences. Small variations occurred in the reds and I sought to describe these to a client in words. Colours need adjectives like ‘bright’, ‘dark’, ‘dull’ etc but one inevitably ends up with a comparison to a universally understood coloured object, such as a poppy, a pillarbox, a brick, a patch of rust, a rose. We take this for granted but it’s very sophisticated, relying on a well-established set of understandings. We often need an object when we describe colour.

In her book Tintes y Tintoreros de América, Ana Roquero records the many changes that took place in Central and South American textile practice during the Spanish colonial period. One of the imports from Spain to the New World was an entire vocabulary for textiles. As well as words for machinery, tools, technical terms and cloth and fabric, this included words for colour. These colour words are still alive in parts of Latin America amongst mestizo weavers and dyers, when their use in today’s Spain is long lost.

In this case it’s the itinerant word that has preserved the colour, and I find that fascinating.


Links

Radiolab broadcast ‘Why Isn’t the Sky Blue’ here

The Himba and the perception of colour Anthropology and the Human Condition: here

Books:

Roquero, Ana, 2006, Tintes y tintoreros de América: catálogo de materias primas y registro etnográfico de México, Centro América, Andes Centrales y Selva Amazónica, Ministerio de Cultura, España

Deutscher, Guy, 2010, Through the Language Glass, Heinemann

Comments

Please also check out the very interesting links offered in comments for this page. Many thanks to those who have written and included them

 


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A Purple Pursuit

Orchil: For a few years I have been researching a (mostly) nineteenth century archive relating to a Leeds dye manufacturer. The early fortune and later success of this Leeds company were built on the manufacturers’ skill in the making of a dye called orchil. Orchil is an ancient dye, made from lichens of several varieties, and it dyes silk and wool various shades of purple. It does not need a mordant, a fact that was valuable to the historical dyer as it omitted the expense in the mordant process, and additionally avoided any harshening which mordanting can impose on silk. Purple could normally be achieved with natural dyes only with overdyes, such as indigo over cochineal, but orchil ‘got there in one’.

In its clearest and most beautiful form, orchil dye will give a glorious fuchsia colour and the clarity of this shade is assisted by the purity of the ammonia in which dyestuff is prepared. Historically, orchil was known to impart a freshness and bloom in ‘bottoming’ other dyes – e.g. when used as a base before overdyeing. Orchil was a much used and valuable dye throughout history, although its use is sometimes an enigma. It is often found in costly tapestries, which is surprising as orchil is not at all lightfast – a fact that was well-known.

With the advent of synthetic dyes in the later nineteenth century the use of orchil began to decline. Records in the Leeds archive indicate that large sums of money were still tied up in stocks of lichen in the 1870s and in trying to comprehend the place of orchil in the nineteenth century I found the archive inextricably linked to the history of the colour purple. We will publish in due course but an extract from the abstract of my co-authored paper with Professor Zvi Koren at DHA 32 offers a clue:

One of the more astounding discoveries associated with this archive was that it included a small envelope signed by Charles Samuel Bedford declaring the content of the packet to be ‘Tyrian Purple’. But what was really inside the envelope? Was it truly Tyrian Purple…?

Shellfish dyes: Much has been written on the history of the shellfish dye Tyrian Purple (Imperial Purple, The Purple of the Ancients, murex etc) and its association with wealth and status. There is a lot of utter rubbish online about Tyrian Purple, so beware if you are researching and look for reliable sources, such as those listed in Chris Cooksey’s Tyrian Purple Bibliography, linked below.

Nucella lapillus shells, Somerset

Nucella lapillus shells, Somerset

For the purposes of this particular post, it’s important to realise that long after the method of shellfish dyeing* was lost, probably around the fifteenth century, the reputation of purple as a high status colour lived on. Purple retained a kind of status independent of its original connections to shellfish dyes. There are contemporaneous references to shellfish dyeing (e.g. in Vitruvius, and Pliny the Elder in his Natural History) and something has always been known of the preparation process, although modern interpretations of commentaries vary.

Since the mid nineteenth century chemists, scholars and dyers have researched shellfish dyes and the ancient dye process has been patiently and painstakingly rediscovered. Shellfish dyeing can again be undertaken although it is only seriously done for research purposes: you will see how small some shells can be from the image and only the tiny hypobranchial gland yields dye. In the mid nineteenth century, no-one knew the full process, which is why I found Robert Browning’s poem Popularity (1850s) so interesting when I came across it this week.  Crucially within it is a several-verse reference to Tyrian Purple and shellfish dye. As I couldn’t fathom what the whole poem was about, this reference was a puzzle. I sought out the RPA (Resident Poetry Advisor) who explained it to me, along with some literary context which includes Browning’s life and work, a knowledge of Keats and the poets that imitated him. Popularity is dense and complicated.

Popularity: As I now understand it, and in simple terms, the poem is about inspiration and skill. Browning asks himself about genius, as he did when studying, say, the paintings of Old Masters.  What is genius? Where does it come from? When some ‘poets’ recognised genius in others, as in the work of Keats, they picked up superficial, outward facets of the verse and imitated them. They basked in their hollow cleverness. Browning describes the humbleness of the shells, or conches (‘Mere conchs!’) and celebrates the ‘cunning’ of those who learned how to refine this costliest ‘dye of dyes‘. What’s the humble origin of Keats’ unique genius, he wonders wittily in his last line:

What porridge had John Keats?

Contemporary knowledge in the 1850s

Considering the knowledge that Browning appears to have of dye preparation:

Till cunning come to pound and squeeze
And clarify,—refine to proof
The liquor filtered by degrees

it could be that he knew a little more about the process than was available through classic texts. Henri de Lucaze Duthiers was working on shellfish dyes in the 1850s, but not for dyeing. He was demonstrating the potential to use the molluscs for a photographic printing process. I don’t see enough evidence to draw any conclusions about what Browning knew, but it’s been fun speculating, and a reminder of the magic we dyers experience liberating colour from simple, natural materials.

To read the whole poem Popularity, you can go here, but two key verses are below.

VI.

Who has not heard how Tyrian shells
Enclosed the blue, that dye of dyes
Whereof one drop worked miracles,
And coloured like Astarte’s eyes
Raw silk the merchant sells?

XI.

Mere conchs! not fit for warp or woof!
Till cunning come to pound and squeeze
And clarify,—refine to proof
The liquor filtered by degrees,
While the world stands aloof.

 

NOTE: *Dyeing, as opposed to smearing. Traditional use of shellfish to colour threads and cloth, such as in Oaxaca, Mexico, is not true vat dyeing, but more akin to  surface smearing.


Links about my research, on this blog

Overview  Dyes, History and a chilly trip to Yorkshire

About orchil: Talking Orchil

My research information: Historical Dye studies


Bibliography

Cooksey, Chris (2013) Tyrian Purple: the first four thousand years, Science Progress, 96(2), p 171 – 186

Jordan, Maria (2012) Recreating the life of a tapestry: Fading dyes and the impact on the tapestry image available online from The Institute of Conservation here

Chris Cooksey’s Tyrian Purple Bibliography

Wikipedia on Tyrian Purple


Thanks

With thanks to Dr Maurizio Aceto for some input on dates, Nigel Phillips for giving me the Nucella lapillus shells in Somerset last summer, and especially to the RPA.

 


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French Connections

I’m back from a trip to the DHA (Dyes in History and Archaeology) Conference in La Rochelle. La Rochelle hosted the ISEND Conference in 2011 and so I was already familiar with the conference venue – a former fishmarket, now the exhibition and conference centre  L’espace Encan.

This is a text-heavy post, so here’s a picture of La Rochelle to keep you going.

LaRochelle

La Rochelle

A DHA conference annually attracts a wide variety of delegates from various disciplines. This year there were about 90 of us. Our number included chemists, conservators, artists, historians, researchers working with natural dyes, and students at various academic levels. At a DHA conference you can find yourself sitting next to someone from the British Museum, the Louvre or the Rijksmuseum, or an independent scholar who is simply passionate about parchment. It is a friendly assembly and all are welcome. Even if, as a non-chemist, you sometimes sit boggle-eyed through muscular technical papers full of graphs, analysis and molecular data, there is always something to be learned. I’m told that in early DHA days (this was the 32nd meeting!) there was a heavy bias towards these more scientific analytical papers but that nowadays the balance is more even, with a good mix of historic /scientific presentations. The selection committee who choose proposed papers must have an intensely hard job. Of the 24 or so papers accepted, several intrigued me but as none have yet been published this handful of comments remains general.

Purple Parchments

One paper involved the analysis of  purple-dyed parchments. Very little work has been done to analyse the source of the purple colour in such codices and as far as I understand, there is currently no scientific evidence that shellfish dyes were used on the parchments. Non-invasive methods are normally used in their analysis, essential if precious manuscripts are to be studied without damage, and these methods can make it more difficult to identify dyestuffs. (With a parchment it isn’t so easy to remove a physical sample as it can be from a textile, where a loose fibre may be available).

There was a mention of dyeing parchment with orchil, and my ears twitched. Last year I was asked to dye some parchment samples with orchil – and dye they certainly did. But it was apparent that the temperatures and immersion involved in dyeing with orchil stiffened and damaged the parchment quality. I felt that this method wasn’t viable. Cold-dyeing seemed to yield a more sympathetic result but I have no idea to what extent the parchment quality was affected as I was only sent miniscule pieces of parchment to dye.

In the post-presentation question session it emerged that the term ‘dyeing’ means different things to different people. Some delegates considered ‘dyeing’ could be the layered painting on of dye and not dyeing by immersion, as working dyers think of it. Now, I should say that I tried painting orchil on too, but soon lost the will to live. It would be immensely protracted to paint on sufficient orchil to build up a good colour. That’s not to say it would be impossible, I just didn’t have the time or the resources to continue.

It will be interesting to learn more about this research. Maybe at Glasgow and DHA 33 next year? The dates are October 30th – 31st 2014.

Shearings and Clippings

Magnified images had been studied by the presenters which showed lumpy-looking particles in the red lake used in several medieval paintings. These indicated that they were reclaimed dyes from red-dyed wool, made into lakes for painting. The reclaiming of red lake pigment dyestuffs from clippings of dyed wool revealed that it made good economic sense to extract the dyes and to reuse them as painting materials. The dyeing of red, from whichever dye source, was expensive and thus waste material might be reprocessed. Again, I encountered problems with a mutual understanding. Initially I was confused by the words ‘shearings and clippings’ which were used by the presenters. I associate these words primarily with sheep-shearing!  In the paper the words referred to waste dyed cloth after cutting woven material – or yarn.

The finding of these ‘reclaimed reds’ isn’t in itself new. A 1996 paper by Jo Kirby and Raymond White goes into great detail (find it here) and also lists a  number of paintings in which red lake pigment dyestuffs have been found. Have a look. You may be amazed.

Networking

A couple of years ago, at DHA in Lisbon, I presented a paper about the trade in dye lichens from Angola through Lisbon. I have yet to publish this, for several complicated reasons. But I had an interesting conversation with another delegate which led me to sending a very small quantity of dye lichen and a recipe to the University of Évora. I heard no more, and forgot all about it. At La Rochelle my Portuguese colleague and  her team presented a paper in which they had measured and tracked the breakdown of the depsides and depsidones (the dye precursors) in the orchil preparation process until purple chromophores formed. Chromophores are the part of the molecule responsible for colour. The chemistry was patiently explained to me in a coffee break and I now understand rather more about the process that before – although I wouldn’t like to take an exam just yet. DHA is great for this kind of contact and co-operation.

DHA=GFZ: A Gremlin Free Zone

If you read the previous post you will now that I was co-presenting a paper at DHA 32  and I wrote about the snaggly-toothed IT gremlins that lurk for unprepared presenters. I am pleased to report that my eminent co-author, Zvi Koren, had done an admirable job on gremlin-bashing (he’s ace at puns too) and everything loaded and presented totally as expected. So did everyone else’s, and we all benefited from calm, unobtrusive technical expertise delivered by Florent Glatard of ARRDH- CRITT Horticole. Our presentation was really well-received but I will not be writing about it until formal publication.

Thanks to DHA 32 organisers Anne de la Sayette and Dominique Cardon

Anne de la Sayette is the Directrice of ARRDHOR – CRITT Horticole, a ‘centre of research, innovation and technology transfer in horticulture’. Dominique Cardon is well known to most natural dyers as author of Natural Dyes: Sources, Tradition, Technology and Science. She is also Emerita Senior Researcher at CNRS, the French national centre of scientific research. CIHAM UMR 5648 CNRS  (an institution, not a mathematical  equation..)  is one of the most important research centres in France for history, literature and archaeology of the Middle Ages. A new book by Dominique is about to be published but I don’t have the details: as soon as I do I will add them to a post.

Carnac

If you have got this far you deserve a pictorial prize. Using photos from DHA is tricky as I feel I should ask people’s permission before posting their images on a blog, so here is something rather special from the trip home.

I had never been to Carnac in Brittany until last week and I had no idea of the scale and breadth of the entire site. But it seemed most serendipitous to discover, on some stones of the alignments, a quantity of orchil lichen. Naturally, I did not touch it. But here are some images to reward stalwart readers. The orchil lichen is in the left hand image only.


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Reasons to be Stressful

Presentations

I’m halfway between two presentations. The first was for the 6 Guilds of Weavers, Spinners and Dyers at Stratford where I spoke about orchil and how the trade in lichen dyestuff reached global proportions in the late nineteenth century. I thoroughly enjoyed my day at Stratford which included a talk by co-speaker Joan Baxter on the way the East Sutherland landscape influences her tapestries. Her recent collaborative work with dancers Between the Web and the Loom was interesting and she showed some video clips. But I can’t find any images on the internet to provide a link beyond this one (about the dance) and this one (about the tapestry she wove).

The second presentation is for the Dyes in History and Archaeology Conference (DHA) in La Rochelle, France. That’s later this week, is about something else entirely, and it’s going to be rather sensational.

Friday 4th October

11:45          Treasures from a Leeds Dye Chemist: A Century-Old “Tyrian Purple”?

                   Isabella Whitworth, Zvi C. Koren

If you want to know more about the sensational, come to La Rochelle. Otherwise, I’m sorry, you may have to wait a little. To download the whole DHA La Rochelle programme, visit this page and follow the links at the bottom.

For the moment, here is a taster in the form of some images. You will see two men, both chemists. There is a brother and a sister, and the son of a famous father.

Lectures and technology

Those who are of ‘a certain age’ will remember that one of the worst things that could happen when giving a lecture was that you dropped all the slides just prior to going on stage then reloaded them upside down, in the wrong order and back to front.

Technology wasn’t satisfied with such piffling levels of stress. So it created Macs and PCs and system updates; memory sticks and SD cards and PowerPoint and embedding. It now arranges that hosts provide an ancient laptop unable to read anything post 1910;  it organises missing leads, the wrong leads, deflating batteries, clickers that die, videos that won’t load and projectors which will have nothing to do with your laptop.

I have watched entirely respectable speakers show a presentation devoid of images because they haven’t checked their Mac presentation on a PC – or haven’t embedded their photos.

As a result I am obsessive about options. At the 6 Guilds event I took my own Mac laptop, own projector, requisite leads plus a boggling array of memory sticks and SD cards correctly formatted and checked out on a neighbour’s PC. In fact, the options proved unnecessary as the 6 Guilds laptop was up-to-date, the memory stick loaded, and two super-calm techies were in control.

For DHA, all presentations have to be sent in advance of the Conference which is good sense – in theory. You will be informed that something has arrived, but you still don’t know if the presentation shows exactly the way you designed it. So, when you get there, you need to check – and have some options up your sleeve. I didn’t do the DHA PowerPoint: my co-author did, for which I am deeply grateful. It can all be his fault.


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Talking Orchil

Canterbury graveyard, 1960s sketchbook

Lichens in a Canterbury graveyard: from my 1960s sketchbook

In my last post I started to write about orchil, and how I became fascinated by its story through my researches on an eighteenth / nineteenth century Wood & Bedford / Yorkshire Chemicals archive.

To start at the beginning, orchil (pronounced or-kil) comes from lichens. It has been used for millennia to dye wool and silk a purple colour. There is some confusion over ancient recipes for purple. It isn’t always possible to decipher which recipes refer to lichen and which to shellfish dyes. Both dyestuffs produce a remarkably similar colour, were to be found in the same areas (e.g. the Mediterranean coast) and descriptions of lichen are often a little vague. For instance, dyestuff might be referred to as a plant, or a moss, or a seaweed.

There is evidence (Pliny, Theophrastus, Dioscorides) that orchil was used in conjunction with shellfish purple and it’s a ready assumption that this was done  to defraud – which of course it may have been. The processing of orchil would have been significantly cheaper than for shellfish dye. But the combination was also undertaken to produce a legitimately cheaper alternative to pure shellfish-dyed cloth. Nevertheless, orchil and shellfish-dyed cloth seems regarded with disdain because of the great and unique reputation of shellfish purple, and orchil’s tendency to fade.

The beauty of fresh orchil on woollen yarn

The beauty of fresh orchil on woollen yarn

Orchil dye is extremely beautiful in its first, fresh bloom of colour but it normally proceeds to fade fast. It is therefore interesting to read a 2012 paper (link below) in which Casselman and Terada demonstrated that a combination of orchil and shellfish dye may in certain circumstances, stabilise the orchil. They also reported that the  use of orchil as a base dye would to some extent neutralise the intensely unpleasant odour of shellfish-dyed cloth. Those facts cast an entirely different light on the historic combination of orchil and shellfish dye.

It occurs to me that in more recent days, far from being ‘poor man’s purple’, orchil could have been considered a great luxury. If you could afford the rich glories of orchil-dyed silk, and these would be obvious to all by the colour, it might indicate one’s financial indifference to fading and the realities of a soon-spoiled garment.

Dye lichens

Not all lichens will dye, not all dye lichens will make orchil. Orchil-producing lichens (and there are innumerable species) contain precursors of the dye and to make this available the dyestuff must be crushed in ammonia or stale urine and water and then kept well-oxygenated. It undergoes a type of fermentation, and the purple colour develops over several weeks.

Orchil is very sensitive to changes in pH and by adjusting vat strength and acidity, a wide variety of colours can be achieved, ranging from browny reds to reds, pinks and purples.

Crotal / crottles

There are lichens that will dye rusty reds, browns and golds. They are often referred to as ‘crotal’, (a Gaelic word) or crottle, lichen. These require no fermentation and are normally boiled up together with fibre, yarn or cloth. They have been in traditional use in Scotland for centuries and the warm, earthy smell of crotal-dyed yarn is also a moth deterrent. But crotals are not orchils!

Mordants

Neither orchil nor crotal requires a mordant although some historical recipes recommend an alum mordant for orchil.

 

The Wood & Bedford Orchil Story

I found a vast number of items in the archive which related to the nineteenth and twentieth century trade in orchil. A couple of them can be seen in the previous post. The records defined several sources of orchil lichen. Around 1830 these included Scandinavia, Sardinia, the Azores, Madeira,  the Canary Islands and Cape Verde. Political changes and colonial interests affected trading in the later 1800s, as did the slave trade and, eventually, its abolition. A picture emerged of a voracious trade that reached an industrial and even global scale by the mid nineteenth century. There is a certain irony in the fact that stocks of what, in effect, is a non-renewable product were saved by the synthesis of mauveine by Perkin in 1856. The demand for lichen then dropped. Nevertheless, Wood & Bedford,  later the Yorkshire Dyeware and Chemical Company, continued to buy and process orchil lichen well into the twentieth century. I understand that the last unused lichen stocks went to Johnsons of Hendon who presumably used lichen to make their indicator papers.

Lichen ethics

You will see that I have learned to make orchil and to dye samples for research purposes but I don’t use it in my studio work. You can read some of my thoughts on lichen use here. I am extremely grateful to all those who taught me about making orchil and how to dye with it.

Pronunciation

How do you pronounce lichens? I say it to rhyme with kitchens. Most people and academics (ok, sorry, academics are also people)  say ‘likens’. The OED pronunciation makes it official: you can say it either way:
/ˈlʌɪk(ə)n, ˈlɪtʃ(ə)n/

References:

The Politics of Purple: Dyes from Shellfish and Lichens Karen Diadick Casselman and Takako Terada

Natural Dyes: Sources, Tradition, Technology and Science; Dominique Cardon, Archetype Publications

The Colourful Past: Origins, Chemistry and Identification of Natural Dyestuffs; Judith H. Hofenk de Graaff, Archetype Publications

Lichen Dyes: The New Sourcebook and Craft of the Dyer by Karen Diadick / Leigh Casselman