Loss and Dyeing: Fading, Conservation, and Orchil Dyes in Tapestries

This is the first of a several part series of posts on textile conservation at the Rijksmuseum, Amsterdam. 

Go into any historic house or museum with tapestry displays, and you will likely be confronted with beautiful and strange landscapes of cool colours. The current rotation of tapestries 16th-17th century tapestries at the Rijksmuseum from François Spiering’s atelier is no exception to this. Blueish foliage, grey-skinned classical figures clad in indigo, tan, and maybe hints of pink or rusty orange line the room. The detail is exquisite, the colour subtle. You may find this beautiful and calming, and won’t be the first. William Morris found inspiration in this palette and used it frequently in his famous 19th century designs.

The thing is, you and Bill are seeing it all wrong.

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Typical blueish foliage found in many Renaissance era tapestries. This is a detail from a piece Spiering’s studio designed by van Mander c. 1617. It is currently undergoing conservation treatment. The pin is marking an area to be conserved with supportive stitching.

Dye fading is arguably one of the most noticeable and difficult problems with textiles, and often a large problem with any object or artwork that contains pigments. Light is the most common source of colour loss, which presents a challenge when considering conservation versus access. In a very literal sense, colour does not exist without light, although the existence of light has the ability to destroy the parts of a dye compound that are perceived as colour.

When a photon of light hits certain compounds, the energy becomes absorbed, electrons enter an excited state, and energy is emitted back from the molecule. If this light energy has a wavelength of 390-700nm and is directed to the lens of a normal human eye, it is translated by the brain into what we call colour. In darkness, colour does not exist because no photons are present to stimulate electrons into an excited state. Call me a geek, but I find this pithy.

The catch-22 is that this energy, especially if it is in the form of high-energy ultraviolet light, has the ability not only to produce what we perceive as colour, but also can provide the energy required to break up bits of a molecule. There are certain characteristic structures that result in emission of light in the visible range, and it only takes a very minor disruption to alter or destroy a molecule’s chromatic properties.

This, by the way, is why most rooms in museums with tapestries are pretty dark. It’s just damage control.

While colour is an important aspect of all dyed textiles, the pictorial aspect of a tapestry makes it particularly crucial. Aside from adding a little physical and visual warmth to a cold castle hall, tapestries are essentially large pictures, which informs conservation decisions. A paintings conservator, for example would not typically choose to conserve the weave structure of the canvas at the expense of the oil painting above it. Conversely, an historic costume often is still very meaningful if the cut and construction are intact, even if the original colour has been lost.

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Tapestries can be amongst the oldest non-archaeological textiles in museum collections, generally ranging from the 16th century onward. That’s a lot of years to hang on a wall, and a lot of hours of daylight to slowly strip away the image that hundreds of hours of weaving created.

The tendency for dyes to fade was not unknown to dyers and weavers of the past. Certain dyes, although they are temptingly brilliant when fresh, were known to degrade quickly and significantly, and there were often strict regulations on what dyes and recipes were acceptable. Indigo, while a complex dye to produce, creates a brilliant blue with good lightfastness. Yellows, conversely, are on the whole more prone to fading. This partially explains the cool palette of many tapestries. Many greens were produced by overdyeing indigo and yellow (often from the weedy plant weld); as time passes the yellow compounds degrade and only blue-jeans blue is left.

Reds provide another challenge. Madder is a solid and important dye plant, although the red it produces is often more bright and orange than deep and luxurious. Some tree barks produce excellent and rich reds, becoming accessible for Europe as certain countries expanded their mercantile and colonial power. Brazilwood is one such example, eventually becoming so economically important that the Portuguese named their colony after it. Safflower can also produce beautiful colours from yellow, to pink to red. None of these dyes aside from madder, however, stand up very well to light exposure.

Lichens dyes are another route to achieve stunning reds and purples. Orcein, derived from orchil, sometimes called archill, is a derived from a group of Roccella species that can produce a truly astounding mauve. It does not require a mordant, but instead relies on the ammonia found in stale urine to produce the colour, making it much cheaper to produce than the rare and exorbitantly expensive Tyrian purple. In a basic environment, the colour turns richly purple. As it becomes more acidic, orchil turns red. The Dutch historically called this plant litmus. The eponymous test still uses filter paper soaked in this dye to establish pH.

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Cephalus and Procris, 1549-1631. Designed by Karel van Mander Workshop of Francois Spiering.

Despite the stunning colour, orchil dyes are sadly far from colourfast. In fact, it was among the regulated dyes, and its poor resistance to light fading was well known amongst dyers and weavers guilds. This brings us back to Spiering, the Rijksmuseum, and why we are all wrong about how tapestries look.

Francois Spiering (c. 1576-1630) moved from his native Belgium to the Netherlands in 1591, where he established a highly successful tapestry studio in Delft. His studio was known for producing technically excellent work with an impressively detailed painterly style, with colours to rival contemporary oil paintings. Karel van Mander the younger began his career with Spiering, and was responsible for the cartoons of many of the workshop’s excellent tapestries.

Spiering undoubtedly knew that orcein dyes would fade, yet analysis shows that he used them extensively. Perhaps it was his artistic sensibility, perhaps he just didn’t care. It’s slightly possible he didn’t know orcein dyes were used in the yarns he purchsed, but I find this highly unlikely. The result is that today, while the subtle modelling and minute detail are still evident, the overall impression of the tapestries is dramatically altered.

When looking at Renaissance and Mannerist paintings, the richness of colours, particularly reds, is apparent. This was part of the aesthetic of the day, and tapestries would have been no exception. Our experience of them is tainted by the passage of time, degradation by light, and the inevitability of chemistry.

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The Worshipping of the Golden Calf.  Karel van Mander, 1602 .Oil on Canvas This painting was done by van Mander, who designed many tapestries in Spiering’s studio. Notice the similarities in composition and style. While the distant landscape is indeed blueish, there is a richness of colour that likely has since vanished in his tapestries. It is also worth noting that pigments, paints, and varnishes are all susceptible to changes from light exposure.

As conservators, usually the most we can do is try to keep these factors at bay. Reducing light levels and eliminating UV while on display and rotating collections can reduce exposure. Maintaining stable humidity and temperature can slow photodegradation. Sometimes a look at the back of a textile gives better clues to how it may have originally looked. However, no physical intervention can ethically and realistically restore a tapestry to its former glory.

Some institutions are beginning to play around with exciting digital options. While the textile itself remains unaltered, digital reconstructions with the use of programs like Photoshop can provide an image that may reveal original dye colours. Light can be projected onto the textile itself, producing a superimposed image of the imagined colours. Experimental dyeing, translations of old recipes, and chemical analysis all provide clues that can help us revisit the past.

Even if what we see now isn’t what was intended 500 year ago, the images are still beautiful masterpieces. Our experience today is inherently different from what it would have been in 1620, if we were ever so lucky as to see such an item of luxury. Investigation and preservation are crucial in maintaining and understanding our cultural heritage, but it’s also important to not mourn the losses. Change is inevitable, degradation is certain. So go to room 2.2 in the Rijksmuseum and see some incredible works that have faded in colour but absorbed five centuries of history.

Further Reading:

http://kalden.home.xs4all.nl/dart/d-p-spieri-f.htm

https://www.rijksmuseum.nl/

Natural Dyeing- Comparing Mordants

Natural dye tests with alum and iron on silk and wool

Synthetic dyes have only been around for about 150 years, which is relatively short in the timeline of textiles. Dyeing with plants, lichens, and insects has been practiced for at least 4,500 years. Although textiles are notoriously absent from the archaeological record, some conditions have allowed for the preservation of fabric that still retains evidence of being dyed. Early Iron Age bog finds from Northern Europe and woven textile scraps from the Hallstatt salt mines in Austria dating from as early as the Bronze Age show the use of natural dyes. In ancient Egypt, cloth from about 2500 BCE has been found to contain dyes, and additional records of dye recipes support the existence of the practice. It is likely that people had been experimenting with dyeing for much longer than this.

While the use of natural dyes is uncommon as a conservation technique due to their unpredictability, it is important to understand the process and its conservation implications. Dye fading, usually by light and UV, can erase or dramatically alter original colours in both natural and synthetic dyes. Seeing what an original colour may have looked like before time took its toll is informative, although it must be noted that the actual hue produced can be incredibly variable based on the species, origin, and growing conditions of the dye material as well as an almost infinite combination of dye processes and recipes that depend on concentration, impurities in water, temperature, dyeing times, and nearly any factor imaginable. Undertaking your own dye experiments certainly gives an appreciation for the expertise of dyers from the past!

Fabric is generally dyed by one of three processes: direct, mordant, or vat dyeing. Direct dyeing is the most straightforward, requiring only the fabric, water, and the dyestuff. Turmeric is a common example of this, although it should be noted that it has poor light-fastness, which means that it is likely to fade when exposed to any source of light, natural or artificial. Vat dyes, such as indigo and woad, rely on a more complex chemical process that allows a dye compound that is originally insoluble in water to chemically change and become attached to the fibre.

Mordants, from the French mordre, or “to bite,” are compounds that bind to both the fabric and dye compound, creating a bond strong enough to prevent the dye from being washed away and result in fading or loss. While these compounds are usually metal salts such as iron, tin, and alum, tannic acid has also been used.

The choice of mordant affects both the colour achieved and the strength of the fibre itself. Iron is what is called a “saddening” mordant, as it tends to produce colours that are duller, cooler, and darker than alum, even when the same dyestuff is used. It can be utilised to produce the somewhat elusive black. Unfortunately, iron mordants often cause weakness within the fibre. This can sometimes be seen in printed textiles and tapestries when only a certain colour such as black or yellow appears to have deteriorated.

Despite the impressive range of hues achieved in historic textiles, the number of dyes actually utilised is relatively small. For one of our last days of the term, we got the chance to play around with some of these dyes. In addition to dyeing cotton with indigo, we also carried out mordant dyeing with iron and alum on wool and silk. For reds, we tried the oft-used madder root and the insect dye cochineal. We also tried out old fustic for yellow and logwood, which was often used to produce a range of blues, purples, greys, and blacks.

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Dried madder root, used in dyeing oranges and reds.

The end result was an interesting comparison between mordants and materials. Side-by-side, it was easy to see the “saddening” effect of the iron mordant, which produced a more sombre set of colours than the cheerful red, yellow, and orange created by the alum mordanted fibres. The rich red and sunny orange produced from cochineal and madder on alum turned to a warm brown and blue-grey with iron. The silk, with its smooth and glossy surface lent a lustrous richness to the colours that was dampened by the rough surface of the wool fibres.

It was interesting to be able to sense the weakness introduced by iron mordanting even on new fibres. The wool in particular seemed “fuzzier” than its alum counterpart, and it was easy to see how the fibres would be more prone to breakage. Despite some of the beautiful complex colours created by the iron mordant, this experiment has actually nudged me away from using iron in my personal dyeing, as I have concerns for the longevity of my products.

Although I have done some natural dyeing myself, each time is a learning process. Of the four mordant dyes, I had only ever used madder with alum, and actually achieved a much calmer red as compared to the bright orange that we got in the lab. That alone highlights what is so difficult but interesting about natural dyes. The unpredictable nature is both nerve-wracking and delightful. I am looking forward to using beautiful, rich cochineal and subtle logwood purple in future projects, as well as trying more overdyeing combinations.

For a little more dye history and chemistry:

Natural History Museum – Seeds of Trade

Encyclopaedia Britannica – Dye

Some more on natural dyeing:

Paradise City Homestead- Dyeing with Marigold. Although marigold isn’t an historically important dye, it does produce a beautiful, cheery golden yellow with alum on wool.