The rarest blue - by Baruch Sterman with Judy Taubes Sterman
The remarkable story of an Ancient color lost to History and rediscovered
Along with rocks and minerals, indigenous plant life also offered a source of color for the ancient world. Dyes that didn't run, fade, or wash out were precious. For nearly two millennia, all along the coast of the Mediterranean, from Jaffa to Djerba, shellfish dyes ranked among the most desirable commodities of the ancient world - and among the costliest. Battles were fought over control of the dying industry and strict law regulated the manufacture and use of the dyes.
By around 650 CE, following the Arab conquest of the Levant, shellfish dyeing, for all intents and purposes, disappeared. The secrets reminded hidden from the world for more than a millennium - until a chance event off the coast of Spain. A young zoologist stood on his boat in the Mediterranean Sea and looked with great curiosity at what a fisherman was doing. The man was showing off; he had broken open the shell of an ordinary-looking snail and was smearing his shirt with its slimy contents. Yellowish Stains streaked the shirt. But as the zoologist watched, the yellow streaks slowly changed color, turning first to green, then gradually miraculously becoming a beautiful, brilliant purple -0 a purple not seen since antiquity.
As Zoologist (Frenchman Lacaze-Duthiers) discovered, three snail species were used for dyeing in ancient times - Murex trunculus, Murex brandaris and Thais haemastoma- and all three belong to the same family of mollusk. From these mollusks a broad spectrum of colors can be produced, all subsumed in ancient times under the term purple.
Each murex provides only a few drops of the precious secretion; it takes more than 20,000 snails to produce just one kilogram of dyed wool. Prescribed as decorative colors for the holy Temple, both purple and blue formed an important component of the ritual garb of the priests. the Bible in the book of numbers, requires all Jews to tie a single thread of tekhelet to the fringes on the corners of their garments as a reminder of the daily obligation to fulfill the commandments. the sky blue color also had powerful religious significance. It evoked the cast, deep oceans, the boundless heavens and by the association, the one infinite, unfathomable God of the Universe.
A few miles south of Heraklion (the capital of Crete), lie the ruins of the Palace of Knossos, where according to Greek mythology, the great king Minos ruled. Minoans were the earliest to discover the highly complex labor intensive process of dying wool using secretions from sea snails. Some assert that an island off the coast of Qatar (Al Khor) was in fact the site of the earliest production of the shellfish dye.
The book of Numbers states:
The Lord said to Moses: Speak to the Israelites and instruct them to make for themselves fringes on the corners of their garments throughout the ages; let them attach a cord of blue to the fringe at each corner. That shall be your fringe; look at it and recall all the commandments of the Lord and observe them, so that you do not follow your heart and eyes in your lustful urge. Thus you shall be reminded to observe all My commandments and to be holy to your God.
Rabbi Meir said: Whoever observes the commandment of tzitzit, it is considered as if he greeted the Divine Presence, for tekhelet resembles the sea and the sea resembles the sky and teh sky resembles God’s holy throne.
Kala ilan a plat driven indigo, identical in almost every way to the blue dye obtained from the murex snails. But it is not the same from the context of religious legitimate based on the above connections to God’s holy throne.. The origins of the phrase kala ilan is not completely understood. Kala in Sanskrit mean blue, deep blue or black. The second word ilan means plan to tree in Hebrew. What we may also never know is which preceded which, indigo or shellfish dyeing.
Julius Caesar famously wrote of the custom of ancient Briton warriors to paint themselves blue: “All Britons, in fact stain themselves with woad, which produces a blue color so that they are more terrifying to face in battle.
A Hindu Siddha medicinal recipe mixes indigo with honey to help alleviate jaundice and diseases of the liver. Online you can buy hair old from Kerala, India made from coconut milk, gooseberries and Indigofera tinctoria, which promises to reduce hair loss and aid in growing long dark and lustrous hair. IN traditional Chinese medicine, indigo detoxifies the blood and reduces inflammation, while in S. Africa, it mollified toothaches.
The ancient didn’t understand the underlying chemical process. All they knew were the appropriate quantities of the various ingredients and the sequence of steps that somehow resulted in the rate and valuable color. Given lack of scientific understanding, all sort of superstition arose about dying process and about the power of indigo. Some cultures, believed that it was specially a menstruating woman who it was thought could ruin an entire crop of indigo plants, if she walked past.
Many hundreds plants produce indigo, the most important being Indigofera tinctoria, from teh pea family, which grows best in tropical and subtropical climates and Isatis tinctoria, a flowering plant related to cabbage and horseradish that grows in other regions including Europe.
Indigofera tinctoria could yield large volumes of transportable dye. In colonial India, indigo plantations supplying dye to Europe formed a pillar of the economy. Toward the end of the fifteenth century when the sea routes to India and China opened following Vasco da Gama’s famous expedition, indigo became one of the chief commodities imported along with such other exotic items as black pepper, nutmeg and opium.
The indigo of the British Empire also grew on colonial plantation in India, founded in the 18th century. The ruthless exploitation of farmers by zamindars who forced farmers to plant indigo rather than food crops led to revolt in Bengal in 1858.
The fact is that the laws of physics impose limits on the generation of blue and those laws are unyielding. they permit only five natural ways to make blue and of those only one can act as the basis for the biological process that lead to the formation of the blue dye molecule, The first four produce the blue of sky, of some birds’ feathers, of the ocean and of certain precious gems. The fifth process is responsible for all the color in our world, from green grass and yellow bananas to red flowers and brown rocks. But the immutable laws restrict the possible range of colors and excluded blue with the exception of one unique molecule that as it happens, can also attach to wool. Understanding the nature of blue, of color and color perception in general, and why the indigo molecule can defy all odds and yield a color fast and permanent blue dye requires at least a general acquaintance with some concepts of physical, biology and neurology.
The first and most ubiquitous physical process that leads to the creation of the blue is what gives the sky its magnificent azure color. When light from the sun strikes air molecules and dust particles in the atmosphere, it sets them air molecules electronically, essentially turning them into tiny antennas that scatter the light in all directions in a process known as Rayleigh scattering in which blue light scattered nearly 10 times more efficiently than red. When we look at a clear noon sky we see the sun’s blue light scattered back to our eyes. When the sun sites on the horizon, we see the rays through an atmosphere that has scattered out the blue, leaving the beautiful reddish skies of dusk or dawn. Larger particles in the air, like water droplets in a cloud, scatter incoming lights, but without preferring one wavelength over another,. As a result, all the wavelengths of the spectrum scatter together and we perceive the combination of colors as white.
The second method of producing blue has to do with a property of waves known as interference.
When light reflects from every structured and regular patterns, the geometry can favor specific wavelengths by inducing constructive interference of a specific color. The brilliant hue of the blue morpho butterfly and the bright blue of some flowers reflect this type of structural color generation, Sometimes color depends on the angle of reflection.
In molecules, absorption process is the main source of all color generation. When hit by photon, a molecule can absorb its energy and each molecule has a unique set of specific wavelengths that it will absorb. Blue is so scarce because not many substances absorb light in red sphere. Since creating blue color requires absorbing red, nature is constrained from generating that color.
The color of the ocean represents the third way in which nature creates blue. Water just barely manages to absorb some red, so that it appears blue. Since this absorption is very weak, you need large volumes of water in order to perceive the blue color.
The fourth way that natures creates blue involves a process described by ligand theory. Atoms in crustal, called ligands surrounded a central atom and bond with it. When a metal impurity centers a crystal lattice, it can distort the electric field and create a situation where electrons pass from one atom to another. This charge transfer or electronic transition often happens at energies with the visible range, producing the striking colors of gemstones. The regular structure of crystal gems forms at high temperatures and intense pressures, such as those found in the Earth’s interior. Biological processes cannot create them, so charges don’t happens in organic substances. The Prussian blue crystals that rebbe of Radzyan created from cuttlefish ink mixed with iron resulted from the same inorganic ligand process and requires the intense heat of the Hasidic cauldrons.
In order to achieve blue by means of the fifth method, a substance must absorb photons only in the red-orange range. Blue formed by the absorption of red-orange photons occurs extremely rarely since the atoms and molecules that constitute matter simply have no way of those photons. The exception is a lovely little molecule - produced by some plants in the pea family and also by some sea snails - called indigo.
The laws of nature seem to have a predilection for beauty, elegance and simplicity. In physics, the yardstick that measures those qualities is symmetry. Indigo molecule has such symmetry. Rotating an indigo molecule 180 degrees leaves the structure changes. In other words, if you draw the molecule on a sheet of paper and then turn the paper upside down, all the atoms are in the exact position as they were before the rotation. Indigo is a compact and simple molecule that exhibits a high degree of symmetry in both its ground and excited states. As a result, of the convergence of these characteristics, shifting between states requires relatively little energy compared to other molecule transitions. These lower energy requirements corresponds to photons of longer wavelengths which accounts for the unique property of indigo to absorb in the red-orange region of the spectrum.
Blue is the color of desire and of yearning for the infinite, for what will remain forever out of reach. the blue flower (Blaue Blume) that represents this yearning in a famous novel by Novalis became a defining symbol for the Romantic movement in Germany. On the other hand, blue represents the color of not of doubt or the intangible and mysterious, but of steadfastness, trustworthiness and fidelity - true blue. In Islamic cultures blue protects and blue doors ward off evil spirits. In medieval paintings the Virgin Mary often wears a blue robe, a custom originating in the early Byzantine Empire when it was the clothing of an empress. The Hindu god Vishnu and his avatars Rama and Krishna are blue;
Book mentioned in this book:
“The history of a color”, Michel Pastoureau
In the objective Eye: color, form and reality in teh theory of Art by John Hyman.