Blue is the Rarest Color: Language and Visual Perception

ultramarine blue monochrome painting with visible texture
“Yves Klein blue,” or International Klein Blue, is named for the artist who mixed this particular hue and is most associated with the color blue. Pictured Untitled Blue Monochrome, 1955, dry pigment and synthetic resin.

Then Achilles, in tears, moved far away from his companions, and sat down on the shore, and gazed out over the wine-dark sea. (Iliad, 1. 351-353, trans. Stephen Mitchell)

What color is the sea? Perhaps a silver-pewter at dawn, or a deep blue, or a warm green-blue, depending on the particular day, depth, and geographic location —but have you ever described the sea as being the color of claret?

One of the characteristics of Homer’s writing is his use of epithets:  rosy-fingered dawn, swift-footed Achilles. Arguably the most famous of these is his oinops pontos, his wine-dark sea; it appears over a dozen times in the Iliad and the Odyssey, companion books chronicling the Greek siege of Troy, the Trojan War, and then the difficult journey undertaken by Odysseus after the war as he attempts to find his way home back to Ithaca. Wine-dark sea has been the subject of much speculation over the past couple hundred years. Shouldn’t the sea be blue? Strangely, nowhere in Homer’s epic poetry is the color blue ever mentioned. Water, water everywhere, but not a hint of blue.

One of the first people to seriously study Homer’s use of color was the 19th-century classics scholar and British Prime Minister William Gladstone. In 1858, Gladstone published a seminal 1,700-page study of Homer’s epic poetry, which included a 30-page statistical analysis of Homer’s use of color. Gladstone notes that, compared to modern writers, Homer rarely mentions color, and what is mentioned is mostly limited to shades of black and white, with red, yellow, and green making only occasional appearances. Black is mentioned almost 200 times, white about 100. Red is mentioned fewer than 15 times, and yellow and green fewer than 10. Moreover, Homer’s descriptions of color can be, at times, completely bizarre: skies the color of bronze, stars are an iron or copper hue, sheep wool and ox skin appear purple, horses and lions are red, and honey glows green. Most conspicuous, however, Gladstone noted the complete absence of the color blue. Nothing is ever described as “blue.”

an interior room with deep blue crystals growing on the walls, floor and ceiling.
Roger Hiorns’s installation Seizur transformed an empty council flat in London into a sparkling blue environment using liquid copper sulphate to cover the interior, producing crystalline growth on all surfaces. The piece was moved in 2011 and is on view at Yorkshire Sculpture Park.

But Homer’s blindness could not be an explanation for the strange use of color in the Iliad and Odyssey. The existing texts record stories from a longstanding oral tradition. Moreover, once Gladstone sifted through Homer’s texts, he also analyzed the descriptions in other ancient Greek texts and found they too had a conspicuous lack of color terms, limited to mostly shades of black and white—and again, a total absence of the color “blue.” The word didn’t even exist. Did the Homeric Greeks have defective color vision? Was there something physically different about their eyes? Indeed, that was Gladstone’s conclusion: “[The] organ of colour and its impressions were but partially developed among the Greeks of the heroic age.” The ancient Greeks, according to him, were color blind.

Gladstone’s broad conclusion regarding ancient Greek color blindness has been hotly debated through the years. Returning to the specific example of Homer’s wine-dark sea, a number of possible substitute theories have been posited.

Firstly, wine-dark sea is powerful poetry. Author Patrick O’Brian borrowed the epithet for the title of one of his books and modern poet W.H. Auden writes of “ships upon wine-dark seas” in his celebrated “The Shield of Achilles.” But it is important to consider that wine-dark sea might be more than just a gorgeous turn of phrase. Homer likes to describe the sea as being wine-dark following a tragedy. Achilles mourns the death of Patroclus, looking out on the wine-dark sea. Odysseus mourns the death of his men after a shipwreck, where they’ve been swallowed up by the wine-dark sea. In this interpretation, wine-dark sea becomes transformed from an epithet to a metaphor, we are meant to read it figuratively. The sea is dangerous, dark, and deep, rendering the tragic circumstances in the color of blood.

A second theory concerns an obsolete type of French wine called le petit bleu or le gros bleu, a kind of chardonnay that, when filtered through a pulp of red grape skins containing the natural pigment anthocyanin, turns an electric blue color. As of this year, however, the wine is being made again and will soon be made available in the U.S. But was this wine available to the ancient Greeks? It doesn’t seem likely. But according to research by chemist Robert H. Wright and retired classics professor Dr. Robert E. D. Cattley, there is still yet another possibility for a blue wine. The ancient Greeks fermented strong wine, and they rarely took their wine neat. More often than not they would dilute their wine with as much as six or eight parts water. Peloponnesian geology includes large formations of marble and limestone, leading Wright and Cattley posit that the ground water must have been alkaline as a result, perhaps sufficiently enough “to change the color of the wine from red to blue.”

Others have suggested instead that Homer was describing red tide, the phenomenon caused by large concentrations of aquatic microorganisms, an algal bloom. The result is the ocean turning either a rust red or even a deep blood red. Meteorological conditions could also account for the wine-dark sea. Dr. Rutherford-Dyer, who disputes the blue wine explanation, based upon Homer describing wine as being red colored in the Iliad and Odyssey, suggests in Greece and Rome, a British journal of classical scholarship, that high dust content in the atmosphere gives a dark red sunset, which when reflected in the dark sea, gives a “color and texture very close to that of mavrodaphne” (a dark wine made from grapes indigenous to Northern Peloponnese). He also claims to have seen the phenomenon off the Maine coast when the sky carried dust from the faraway eruption of Mount St. Helens in 1980. He further adds that dusty skies indicate slow-moving winds, thus stable weather conditions ideal for sailing, perhaps giving substance to the nautical maxim “red sky at night, sailor’s delight.”

All of these potential explanations fail to account for one very important thing, however: the absence of the word “blue” in ancient Greek literature. The Greek islands are practically surrounded by the color blue: blue sky, blue sea—and yet the word for “blue” is conspicuously absent. Gladstone was on to something with his statistical compilation of color use in ancient Greek literature, but as it turns out, his study was a bit narrow: the ancient Greeks were not alone in their limited color descriptions, nor in the conspicuous absence of the color “blue.” Expanding upon Gladstone’s research, philosopher and philologist Lazarus Geiger found the same phenomenon in ancient Hebrew literature, Assyrian texts, Icelandic sagas, the Koran, ancient Chinese stories, Hindu Vedic hymns and Indian epics such as the Mahabharata. It is as though the entire ancient world were living in murky world of black and white, basking under heavy, brazen bronze skies, interrupted on rare occasion by flashes of red or yellow. The only ancient culture to have a word for blue was the Egyptians, as they developed the first synthetic pigment, Egyptian blue (the secret of its manufacture was lost in Roman times, but is thought to have been derived from heating together a quartz sand, a copper compound, calcium carbonate, and a small amount of alkali).

View from high up of blue rooftops on whitewashed buildings with vivid blue sea and sky in the background.
Classic postcard view of Santorini, Greece.

Geiger expanded Gladstone’s research in another direction as well; he was the first to notice there was a universal sequence in the acquisition of basic color terms, an evolution to color perception. Every language has a word for black and white, or dark and light. The next color to appear—again, in every language—is red, the color of blood and wine. Following red, yellow appears, or sometimes green. Both yellow and green are picked up before the last color appears: blue. Geiger’s work was largely forgotten until anthropologist Brent Berlin and linguist Paul Kay published Basic Color Terms: Their Universality and Evolution in 1969. Berlin and Kay proposed the same color hierarchy, adding brown as the next stage, followed by purple, pink, orange, or gray. Berlin and Kay’s hypothesis concerning the latter colors has since fallen out of favor, but the black, white, red, yellow, green, blue sequence remains intact. The problem with Berlin and Kay’s hypothesis, as well as Geiger’s, is that it fails to explain why this sequence exists.

One theory has it that the progression of color perception correlates directly with humans’ survival instincts. It is believed that black and white appear first because humans must be able to tell the difference between night and day. Red is important as well, as humans must be able to recognize signs of danger, such as blood or poisonous fruit. Even today, the color red causes an increase in sweat gland activity, an involuntary reaction to signs of tension and alarm. Green and yellow appear in our vocabulary as we found a need to distinguish between ripe and unripe fruit. No matter how sublime the sea or majestic the sky, knowledge of the color blue, it is argued, just isn’t vital for survival. Aside from the sea and sky, the color blue doesn’t appear much in nature. Blue fruits are not common, nor blue flowers. Blue appears only rarely in geology, in the form of precious and semi-precious stones. Blue eyes are also rare, and only appeared some 7,000 ago. And blue animals? There aren’t many, save the occasional bird or baboon’s ass.

Gladstone’s hypothesis that the ancient Greeks were color blind due to physiological defects spurred scientists to investigate the possibility that a similar condition might exist in modern humans, and indeed, these scientists discovered that a small portion of our population has difficulty distinguishing between different colors. Meanwhile, ophthalmologist Hugo Magnus concluded that ancient people’s color blindness was the result of their eyes not being sensitive to colors, and that over time, as their eyes absorbed more colors, their sensitivity to color increased, and that this newly acquired trait was passed on to subsequent generations. Today, however, we know that acquired capabilities cannot be passed on genetically. We also know that it is pretty unlikely our eyes, our organs of perception, have changed to any considerable degree since ancient times. If the rise of color words since ancient times wasn’t due to ocular changes, what might be the cause?

Anthropologists took up the challenge next. They were curious about how color was perceived by traditional cultures with limited or no contact to outsiders. In 1898, anthropologist and psychiatrist W.H. R. Rivers went to the Torres Straits Islands, located between New Guinea and Australia, where he investigated the islanders’ color perception. Rivers was astonished to hear the elders describe the sky as black, and a child describe the sky as being dark like dirty water. Rivers and other anthropologists concluded that early humans and members of  isolated cultures were not color blind. They saw the same colors we see but linguistically don’t distinguish beyond hues of white, black, or red. This might be a simple enough explanation for Homer’s wine-dark sea, but it still raises the question: did ancient peoples perceive the color “blue”?

In 2006, researchers led by Jonathan Winawer at MIT presented Russian and English speakers with sets of three blue squares, two of which were identical, and another a slightly different shade. With two separate words to distinguish between light blue (goluboy) and dark blue (siniy), Russian speakers clearly had the advantage; they were consistently quicker to pick out the anomaly over English speakers, suggesting that linguistics does play a strong role in color perception. These experiments’ conclusions support the famous hypothesis proposed by American linguist Benjamin Whorf in the 1930s, which suggests that our words literally shape how we categorize the things we observe in the world around us.

Similarly, researcher Jules Davidoff traveled to Namibia to investigate possible links between language and color perception, specifically addressing the question of whether you can truly see a color if you don’t have a word for it. Davidoff performed an experiment with members of the Himba tribe, who speak a language that has no word for “blue.” Instead, their term conflates the colors blue and green, offering no distinction between the two. (As this is not entirely uncommon across cultures, linguists have taken to calling this combined color “grue.”) When shown a circle composed of 11 green squares and one blue square, the Himba could not easily pick out which one was different from the others. Considering the color green, however, the Himba have a wider vocabulary than English speakers. A reverse experiment was devised, with 11 consistently green squares and one square a slightly different hue from the rest. Himba tribe members could immediately spot the difference, while native English speakers consistently failed. Davidoff concluded that lacking precise color terms makes it more difficult for people to discern such differences.

Before the color blue became a common concept, perhaps humans saw it but simply didn’t recognize it as such. Even more fascinating—or perhaps disturbing—is the realization that the way we perceive the world around us may be something of an illusion, a trick played on us not by some external force but by our own minds, shadows cast against the back of Plato’s allegorical cave. We are oblivious to whatever realities exist outside of our perception. While we modern humans can differentiate between 1 million colors today, our perception is still largely limited to eleven color categories (in the English language: white, black, gray, red, yellow, green, blue, brown, pink, orange, purple). More humbling is the fact that we humans get by with just three types of photoreceptor cone cells (corresponding roughly to red, green, and blue sensitive detectors). Somewhere, silently scuttling beneath Homer’s wine-dark sea, the modest mantis shrimp boasts 16 different types of photoreceptor cone cells, viewing the world through a kaleidoscopic vision of unknowable colors, the likes of which we can only dream.

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