NATURE'S HIDDEN RAINBOW

After the white snowdrop, the first flowers to bloom in spring are yellow, bringing hope for the sunny summer days ahead. It is also nurturing, both as the Confucian colour of spirituality, and quite literally; many of the plants that give yellow dye are also used in food such as dill and turmeric.

Onions have been cultivated for over 3,000 years. It was the plant most often depicted in Egyptian tomb paintings, and is the yellow dye plant most frequently mentioned in literature; Alexander the Great was said to have fed onions to his armies to ensure their success. Without any colour impact on the plate, it is the papery outer skin of the onion, Allium Cepa, that contains quercetin that gives the yellow dye on wool mordanted with alum – even when the onions are red. This yellow dye can produce attractive yellow shades from pale gold to deep yellowy orange. It is however very light sensitive and fades extremely quickly within weeks, even if it isn’t exposed to direct sunlight.

The ancient Romans used weld as the best source of a light-fast yellow, although the secret was already known in Neolithic times as weld seeds have been discovered in excavations of Neolithic sites in Switzerland. According to Pliny it was used exclusively for women’s clothing, especially wedding garments and the robes of vestal virgins. It also has a long history of being used in combination with other dyes to enhance or modify colours. In Coptic textiles of the 3rd-10th centuries it was used with madder to give shades of orange, and with indigo to give shades of green.

Orange in its true form elusive. There are many plant dyes that produce pleasing russets and golden browns but a true blend of red and yellow, bright like the fruit, is rare. In Confucian philosophy the blending of fiery red and noble illuminating yellow created a transformative colour that represents sensuality and spirituality. In modern colour theory it is the colour of communication: perhaps one of the reasons why the Buddha chose it 2,500 years ago for his followers to wear on their path to spiritual enlightenment.

The robes of the Buddhist monks were made in the simplest way, often of reclaimed rags which were stitched together creating a pattern like the paddy fields on the hillside. The only dyes permissible for the monks to use were from roots and tubers, leaves, bark, flowers and fruits, the most typical being the heartwood of the jackfruit tree, ochre and saffron.

Saffron has been cultivated as a dye plant since ancient times when it coloured the robes of Persian emperors and kings. Worth its weight in gold, it is the stigma of the violet-blue petalled Crocus Sativus flower that is dried to produce saffron. Saffron is distinctive as a dyestuff as it is able to reach an excellent density of colour without a mordant.

In the ancient Roman era, woad was synonymous with the intractable ancient Britains who put up such huge resistance to being colonised. Maybe it was the sharp spear shape of the dark bluish green leaves that inspired the Iceni to daub themselves with woad in preparation for battle, or maybe the natural antiseptic of the leaves: either way woad left a fearful and lasting impression on all those who faced them.

Even at the turn of the 20th century, those who worked with woad Isatis Tinctoria were identified by their blue hands and fingernails. Throughout the Middle Ages woad dealers in Germany, France and Britain had become wealthy from the best source of light-fast blue; as in the saying ‘as true as Coventry blue’ dating to the 16th century when the city was renowned for its excellent woad-dyed thread.

Woad was grown all over Britain from the 16th century. Woad workers or ‘waddies’ would travel to the fields where it was grown to set up woad mills, where the freshly harvested leaves could be ground in a circular trough under three great wheels drawn by horses. The pulp generated was shaped into balls by hand and dried for several weeks to allow bacteria to develop the indoxyl into dye-producing indigotin, before being broken up and re-ground and couched – a kind of moist fermentation – to allow the amount of vegetable matter to be reduced and the dye intensified so it could be ground into woad powder.

Despite being absolutely ubiquitous throughout the plant kingdom it is almost impossible to get a true grass green from a single dye. It has to be over-dyed by turn in yellow and blue, but olive green can be made by adding an iron mordant to some yellow dyes. Artichokes have been suggested as a good source of green as have rhododendron leaves, nettles, black-eyed Susan, and to make a pleasant pale green, the fresh leaves of Lily of the valley. The Natural History Museum recommends using spinach or grass which can simply be boiled to extract the colour in which to steep the fibre, but it isn’t clear on how resilient the colour would be.

Although indigenous to western Asia and the Mediterranean, weld provided the green found in Moroccan carpets and ottoman dyes right through to the 19th centuries. Weld was widely exported and cultivated across Europe, reaching Britain in the Middle Ages with seeds discovered on archaeological sites in York and Perth dating to the 9th-11th centuries. Most importantly, in Britain at least, it was the magical ingredient that when mixed with dyers’ greenwood creates Kendal green. The coarse woollen cloth was so important to the town’s success in the medieval era that the town’s coat of arms bears the motto ‘Pannus mihi panis’ meaning ‘cloth is my bread’, and the cloth was mentioned by Shakespeare in Henry IV, Part 1.

Lincoln green, the colour beloved of Robin Hood, was a combination of weld and woad. Produced in Lincoln, the green woollen cloth was already part of a valuable export trade to Spain and Italy at the end of the 13th century as mentioned in the Venetian tariff of 1265. At that time Lincoln was also known as a centre for fine fabrics ‘dyed in the grain’ with kermes, although it has been suggested that Lincoln green is a corruption of Lincoln in grain.

Extract from the article A Splendid Shade of Milked Snail: Nature’s Hidden Rainbow, written by Aurora Almendral in Issue 57 Meteorological. Find out how to read the rest of the article here:

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