Long Read: The Histories of the Colour Blue

“What’s your favourite colour” is one of those questions that children first learn how to answer.

From a very early age, the world that surrounds them is codified by adults. They are introduced to the rules of perspective (near and far subjects), the iconographic tropes of what is a cloud, the sun, a mountain, in order for them to be able to decipher cartoons and illustrations and to eventually be brought into a common cultural tradition.

But colour is also another code that is taught. Not only the semiotic associations of pairs like blue-cold/red-hot, green-go/red-stop, etc, but also the social and psychological uses of certain colours: boys wear blue, girls wear pink. Love and passion are red, yellow means jealousy, death is black, hope is green...

But why is blue the world’s favourite colour?

In a 2015 survey by YouGov conducted across 10 countries, blue came first on all instances, with percentages that ranged between 23% in Indonesia to 33% in the United Kingdom, putting it between 8-18 points ahead of any other colour.

The second-most popular colour varies more from country to country but it was always between green, red and purple. However, blue was the most popular answer also when the groups are divided by different categories such as age, race, gender or political views.

THE INVENTION OF THE WORD BLUE

Blue is one of the most powerful concepts in our cultural tradition. In English we didn’t even have a word for it until at least 1250-1300 CE (Middle English), when the words “bleu” and “blewe” are first recorded with the meaning “of the colour of the clear sky”, derived from the Old French words “blo”, “bleu” found to have the broad meanings of “pale, pallid, wan, light-coloured, blond, discoloured, blue, blue-grey”.

Linguists have suggested an origin in the word “blæwaz” from Proto-Germanic, a theoretical reconstructed language believed to have been spoken in the South of the Scandinavian peninsula and the North of Germany around 500 BCE.

But even more, the root “bhel-” has been reconstructed all the way back to the Proto Indo-European language (believed to have been spoken between 4500 and 2500 BCE in the Ukrainian steppes North of the Caspian sea) with the meaning of “to shine, flash, burn” or “shining white”, and as part of the word “bhle-was” with the meaning of “light-coloured, blue, blond, yellow”.

The linguistic evidences show us that many Indo-European languages seem to have had one word that encompassed blue, green and grey as one single colour, and what in Proto-Germanic ended up meaning “blue”, evolved into the Latin flavus (yellow), the Old Spanish blavo (yellowish grey), the Greek phalos (white) or the Welsh blawr, (grey).

But, where is the colour blue in all of this?

If we invented a word for it, does it mean that before a certain point in time, blue didn’t exist?

THE COLOUR THAT WASN’T THERE

George Frederic Watts, Portrait of Gladstone, 1859, National Portrait Gallery, London, United Kingdom.

One of the first to notice the elusiveness of the colour blue was William Gladstone, a British politician and scholar who served as Prime Minister on four occasions in the late 19th century.

While reading Homer, he observed that references to colours in both the Iliad and the Odyssey were few and also quite peculiar. Black is mentioned almost 200 times, white around 100. But other colours are much more scarce: red fewer than 15 times, green and yellow fewer than 10.

But, you guessed it: there is no mention of the colour blue.

Blue didn’t exist as a separate concept from that green-blue-grey mix and as such, classic Greek doesn’t have a word for “blue”, because the concept of blue did not exist yet.

He published his book “Studies on Homer and the Homeric Age” in 1858, where he writes about how Homer talks about the colour of sheep’s wool as violet, mentions the green hue of honey, or, in the description that has haunted scholars the most, describes the sea as “wine-dark”.

Ever since these peculiarities were pointed out a myriad of academics has tried to explain logically why Homer would’ve chosen such a bizarre (to us) colour description.

The explanations have gone from chemists trying to link the alkaline nature of the water in Greece with the tradition of diluting wine with as much as six or eight parts of water and the colour of the resulting beverage, to scholars that have suggested perhaps a congenital colour-blindness endemic to the Greeks (this was Gladstone’s proposal), or biologists that have proposed perhaps a red algae infestations in the Aegean Sea to make sense of it.

But other suggest that perhaps this “wine-dark sea” was less a description than a useful poetic device.

Enter Jewish-German philologist Lazarus Geiger, who expanded Gladstone’s study a decade later by analysing other old texts in different literatures and cultures, from Icelandic sagas and ancient Chinese poetry to the oldest versions of the Hebrew Bible, Vedic hymns in Sanskrit or earlier versions of the Quran.

They all share the same characteristic: they never mentioned the colour blue. It might not be a poetic licence after all.

Geiger was the first to detect the existence of a universal sequence of acquisition of basic colour terminology on almost every language: the first two to be differentiated are black and white, that is, dark and light. This is followed by red as a separate entity, then yellow and then green (with some languages alternating the appearance of the last two).

And as we’ve seen, you have to wait thousands of years for a unique word for the colour blue to show up on most languages, and only once it was categorically separated from green and grey.

But, why is blue so controversial? Could our ancestors “see” the colour blue? Why is it putting us in a situation where we doubt even its own existence.

(ALMOST) NOTHING IS BLUE

The short answer is that blue is very rare in nature.

A few minerals, animals and plants sport this colour, however it is very rare to find a blue colour naturally that doesn’t lean more towards either green or violet/purple.

Yes, one can easily point out from the comfort of the 21st century that “large bodies of water” or “the sky” appear to be blue, and that we really don’t need to look that hard to find something “blue” in nature... but if our ancestors didn’t have a separate word for blue, and they perceived blue, green and grey as belonging to a singular conceptual construct that encompassed all of those shades into the same idea, we have to conclude that our conviction that “the sky is blue” is indeed more a cultural convention than a fact.

Furthermore, the blue of the sky or the blue of large bodies of water is immaterial: it is a wavelength that cannot be captured, and most importantly for our story, cannot be made into a pigment.

From the list of very few natural blue substances, the two most common natural blue dyes that exist in nature can be extracted from the mineral azurite or the indigo plant. The first turns greenish with time, and the second is unstable and fades easily when exposed to sunlight.

Our linguistic problem has become a material one.

What if we weren’t able to pin-point what blue was because we weren’t able to make blue?

LAPIS LAZULI

The Kokcha River in the province of Badakhshan, Afghanistan.

The only ancient written culture to develop a word for the colour blue was the Egyptian, and as it happens, they were the only culture to artificially develop a blue pigment. Scholars now call it “Egyptian Blue”, and we can find its traces in the material culture as early as in the year 3200 BCE.

But before we talk about Egyptian Blue we need to talk about lapis lazuli.

Lapis lazuli is a semi precious stone that is very rare in nature. Most of the lapis lazuli even to this day comes from the Kokcha river valley in North-East Afghanistan, one of the very few regions where it occurs naturally and to our knowledge, the only source of this material known in ancient times.

From Afghanistan, a very slow terrestrial route would disperse this precious stone across the world, and we can perfectly trace its footprints archaeologically.

Small beads of lapis have been found in sites linked to the Indus Valley civilisation in modern Pakistan from as early as the year 4500 BCE, travelling slowly via a coastal commercial route all the way to the centre of the Mesopotamian and Nile valleys as early as 3600 BCE at the sites of Tell Brak (Iraq) and Hierakonpolis (Egypt).

On rare occasions, we are able to find small statuettes carved directly from a block of lapis lazuli, exposing the extent of these ancient commercial routes that were able to transport a rock from Afghanistan to Egypt.

But due to the difficulty of working with it, lapis lazuli is rarely used as a pigment and most of the examples we have are from small accent details created using whole pieces of the rock. Only a couple of examples have survived from the ancient world that suggest lapis lazuli might have been occasionally used as a pigment, but these date from 1500-1300 BCE and are very, very rare.

So: how did the Egyptians come up with Egyptian blue, and how was it made?

EGYPTIAN BLUE

The oldest records we have in writing about a synthetic blue are the tributes given to Pharaoh Tuthmosis III by the Syrians around the year 1500 BCE as depicted at the Temple of Karnak.

In the hieroglyphs we find references to two separate materials, “blue” and “true blue”, which archaeologist have suggested they may refer to lapis lazuli itself and our elusive Egyptian Blue.

These two different materials are also found around the same time in Akkhadian cuneiform tablets as “real blue” and “blue from the kiln”, a synthetic glazed material created to complement the increasing demand for lapis lazuli.

Glazed materials were created to mimic the qualities of semi precious stones, and the oldest examples date from already the 3rd millennium BCE. With the rise of metallurgy and probably by accident, the mixture of the remains of metal ores containing copper with the salts present in the animal dung used as fuel in the smelting furnaces would’ve resulted in a glazed coat that would’ve deposited itself on top of the piece being fired.

Having discovered this reaction, artisans started to harness this technique and playing with different materials like quartz, calcite, azurite and different plants to create artificial glazed substances in different colours.

By the mid-2nd millennium BCE Egypt has achieved a sustained glass production with techniques that have evolved so much as to be able to obtain a multitude of colours, including whites, oranges, red and deep blues like the ones seen on the Mask of Tutankhamun. These deeper shades of blue were possible thanks to adding cobalt and natron to the mix.

What’s extraordinary is that archaeologist have found the source of this cobalt ore in the mountainous region of Qasr Lebekha, near the Kharga Oasis. When analysed chemically, the blue glass found around the whole Mediterranean world, from Greece to Turkey to Rome shows traces of this same Egyptian cobalt ore.

Only one other source of cobalt has been suggested outside of Egypt, probably in Mesopotamia or Yemen, but the evidence for this secondary source is very limited and it is still an academic mystery.

For centuries, blue glass was predominantly an Egyptian monopoly, the only real alternative to the costly and difficult to obtain Afghan lapis lazuli, hence its popularity and value.

But blue didn’t stop at glassmaking.

EGYPTIAN BLUE AS A PIGMENT

The same materials used to produce glazes and glass, when mixed in different proportions produce a frit that can be crushed and used to produce a pigment. This was the first successful blue pigment that gave us the magnificent night skies painted in the tombs in Deir el Bahri, the deep blues found in papyri drawings, that is imbued with mystic and religious connotations in Egyptian literature due to its secrecy and alchemical nature.

This pigment shows up all over the Mediterranean, in ceramic vases, sculptures, frescoes, all the way until the Roman era, when, it suddenly dies out.

We have found traces of Egyptian Blue in Roman art, including frescoes found in Pompeii, but by then it has become a secondary pigment used for the background, or to trace the silhouette of a figure.

Romans associate the colour blue with the barbarian tribes in modern Germany, France and Britain, and it is during this time that indigo-dyed clothing becomes popular amongst plebeians, creating a class association that made the colour less fashionable by the patricians and nobles that favoured white, black, red or violet garments.

Blue was quickly becoming obsolete and although we will still find blues made with azurite or cobalt showing up here and there during the Dark Ages in Byzantium and the early Islamic world, the technique to manufacture Egyptian Blue is completely lost by the 5th century when the Roman Empire collapsed.

But as as the colour was being forgotten in the Mediterranean, on the other side of the world a new technique is being developed.

FROM THE DARK AGES TO THE RENAISSANCE: ULTRAMARINE, AZURITE & SMALT

Around the 6-7th centuries in Afghanistan, near the same valley where lapis lazuli has been quarried for millennia, we find the first recorded use not only of pigments made out of this stone, but also of the first oil paintings as we know them today in the painted caves around the infamous Bamiyan Buddhas.

Cennino Cennini, Il libro dell’arte (detail), c. 1390 CE, Biblioteca Medicea Laurenziana, Florence, Italy. Source: Google Arts & Culture

It would take another 300 years for this technique to be brought into the Mediterranean world by Venetian merchants and for the first “new blue” pigment to be developed in centuries, known as Ultramarine Blue (blue from beyond the sea), but not until around the year 1000 CE.

This technique has been preserved in Cenino Cennini’s treaty “The Craftsman’s Handbook” written around the turn of the 15th century.

It consisted in crushing the lapis lazuli into a gravel, mill it finely, mix it with beeswax and other substances to create a sort of clay/dough that is submerged in water. The blue particles are not soluble and sink to the bottom, while the imperfections are either left in the wax clay or dissolve in the water. The result is a very small amount of blue for each piece of lapis stone, making the pigment extremely expensive, with a value even over that of gold.

In Western Europe, the colour blue obtained from cobalt begins a timid reappearance in the stained glass windows of French cathedrals from around the year 1000 CE, but the technique described above to obtain Ultramarine Blue is still the only reliable way of generating a blue pigment that would last and not fade.

It is also around this time that the Church starts to codify the colours used in religious images, and when the Virgin Mary starts to be represented with a blue robe for which the precious Ultramarine Blue was reserved.

Due to its price, artists had to came up with cost-cutting solutions using other types of blue as a base.

The most common technique combines a pigment obtained from azurite, in itself a very greenish blue that wasn’t particularly appreciated, covered with a very thin layer of the expensive Ultramarine Blue.

Another option was using a base layer of Smalt Blue, obtained from a synthetic glass made from cobalt.

Smalt Blue is believed to have originated in Iraq, having discovered the earlier examples of it in Islamic pottery from around the 9th century. In another fascinating cultural movement, this technique travelled in two directions, reaching China where it is believed to have developed into the famous blue and white porcelain of the 14th century Ming Dynasty, and reaching also Europe, where it developed into the white and blue Delft pottery in the Netherlands.

But it is not until the early 18th century that a solution was found for the blue dilemma.

MODERN BLUES

Invented in 1704 or 1706, Prussian Blue is the first synthetic colour in the modern sense. History attributes the invention to the pigment maker Diesbach who shared a lab with the alchemist Johann Konrad Dippel. The first was trying to create a red pigment using cochineal insects, but due to cross contamination with other materials used by Dippel, he ended up discovering a rather marvellous and deep blue.

For the first time in more than 1500 years, artists were able to use a blue pigment that was cheap and easily obtained, that helped expand the artistic vocabulary that crystallised in the dramatic paintings of the Baroque, Rococo and Neo-Classical eras.

The early 19th century saw the apparition of synthetic cobalt blues, including Cerulean Blue made famous in recent years by Miranda Priestly in The Devil Wears Prada.

And, finally, in 1824 Jean Baptiste Guimet was able to create the first synthetic Ultramarine Blue, more than a thousand years after it was first used by a group of Buddhist monks in some caves in Afghanistan, and almost around the same time when William Gladstone published his “Studies on Homer and the Homeric Age” after he noticed the curious way colours were described in ancient Greek literature, tying both our stories together.

EPILOGUE

Linguists believe that languages only need names for colours when the culture is able to manufacture them. For centuries, we lost the ability to easily manufacture the colour blue and only in the middle ages this technology was slowly rediscovered. It is not surprising that it is not until then that most languages were able to develop a predominant word for the colour blue out of the many different shades, as a separate category from green and grey.

Different studies conducted by psychologists show the difficulty or easiness that cultures have when discriminating between very similar shades of colour if they posses or lack a specific word for them.

Once a language creates a word to separate shades into different thematic categories, our brain becomes more accurate at “seeing” the distinct shades as separate entities, even if the empirical experience of colour (as light with a particular wavelength) is unchangeable.

After the Second World War and with the advances in synthetic organic chemistry, colour manufacturing lost most its mysticism as we are now able to create any shade imaginable, a process multiplied millionfold with the advent of digital technology and Ultra-High Definition screens.

The colour blue has maybe abandoned the realm of the alchemical, but to me at least, it is still very much a mystery. It is the world’s favourite colour because we have willed it into existence.

Next time you look at the sky, think about how much of what you think reality is, is not but just the result of thousands of years of cultural evolution.