color theorist: blue

Blue seems to be quite an integral part of the human experience. Blue skies. Blue eyes. According to Regina Spektor it's the most human color. Profane comedy? Blue. Feeling sad? Even bluer. Smurfing smurfy? The bluest. We teach children that It's a primary color, though you'll see why that's technically a big fat lie when color theorist covers the color wheel, but let’s get back to the issue at hand... Blue. Is. Everywhere. Or is it?

rgb blue, hex color #0000FF

What even is blue?

Let's begin our journey with a brief science refresher. Sunlight contains rays of light of all wavelengths visible to the naked eye, from red to blue (which scientifically includes the colloquial rainbow shades "indigo" and "violet"), as well as light at wavelengths invisible to the naked eye (infrared and ultraviolet). As these rays pass through our atmosphere, certain elements absorb some wavelengths of light, and other wavelengths get reflected. Our eyes use cones to absorb that reflected light, then our brains process and interpret that information as colors, with different wavelengths being processed as different hues. Longer wavelengths contain less energy and appear at the red end of the spectrum, and shorter wavelengths contain more energy and appear blue (this is why high-energy flames appear blue, despite our association with blue as a “cool” color). Shiny gold star for those still with us.

Our sky appears blue to us because the oxygen and nitrogen molecules reflect and scatter blue wavelengths of light. Water also appears blue because of its absorption of long light wavelengths. We only see the sky and water as blue because the molecules in them reflect blue light. Technically, that may mean the molecules themselves are “blue,” but for practical purposes, we can’t ever use those molecules (in their natural state) to create, say, a certain hue of dye or paint.

you might recognize our good old friend, the sky. :: photo: public domain

Early civilizations didn't even have a concept of the color blue. It didn't appear to them naturally, except in the water and sky, which were thought to many to be inarguably colorless. Human concept of color only exists by comparison and since there was a dearth of anything conceivably "blue," it was virtually impossible to compare the color to another, and therefore unnecessary to communicate, and virtually indistinguishable (more on this later).

Natural blue pigment does exist, but it is surprisingly rare. Botanist David Lee points out in Nature's Palette: The Science of Color, that fewer than 10% of flowering plants in nature produce blue flowers (think hydrangea or morning glories) and none of the pigment we are seeing is actually blue. The color is created by plants using a red pigment called anthocyanin that is displayed with other color pigments to create bluish hues. Blueberries are blue because of anthocyanin as well. In animals, "blue" fur and feathers appear that way from reflected light, and only one animal in existence produces a true blue pigment: the obrina olivewing butterfly.

obrina olivewing butterfly :: photo: Didier Descouens

In the natural world, outside of water and sky, the vast majority of blue exists in mineral form. It makes sense, then, that the color became incorporated into the human lexicon only after we developed a method of producing blue pigments by manipulating the proper minerals. We can credit the Egyptians with literally inventing blue. They produced their pigment from a heated mixture of limestone, sand, and a copper-containing mineral (commonly azurite or malachite). Today we refer to this color fittingly as Egyptian Blue. It was the first of many famous hues to be synthetically produced by humans since (cerulean was a thing more than a century before Oscar de la Renta was even born, Ms. Priestley).

egyptian blue hippopotamus (“william”) :: egypt :: c. 1961–1878 b.c.e. :: photo: metmuseum.org

At the same time in history not a single other culture that we know of had a word for blue, and to this day, at least one still doesn't. But if there is no word for blue, does the concept of blue still exist? Well, remember how we mentioned previously that color only really exists by comparison? Well we did, and a 2006 study by Jules Davidoff reinforces that idea. His team studied the Himba tribe of Namibia, who do not have a word for blue, nor do they communicate any distinguishable difference between blue and green. In the study, the tribespeople were shown a circle of colored squares, one blue, the rest green, and though explaining the difference might seem easy to us, they had significant difficulty telling Davidoff how the square differed from the others.

the blue one seems pretty obvious, right? :: himba color experiment :: photo: Vidipedia

Conversely, the Himba tribe has many different words for varying hues of green, so when they were presented a similar setup, but with one of the squares a slightly different green (instead of blue), they easily and immediately were able to identify and explain the deviant hue, which we would tend to see as almost imperceptibly different, especially in comparison to a blue square.

can you find the different shade of green? :: photo: Vidipedia

even if you found the right one, it’s not nearly as obvious a difference to us as the blue square, right? :: photo: Vidipedia

So blue is a pretty fucking complicated color. We see it when it isn't there, and it's hardly there in the first place. Some of us can’t understand it at all. In ancient literature, when colors were being used to describe things we now know to be blue, it’s apparent humans weren't quite on board yet. Famously demonstrating this lack of blue awareness, the ancient Greek writer Homer described the unmistakably blue color of the Mediterranean Sea as "wine-dark," in The Odyssey. Despite modern color availability, we still don’t know if we’ve even seen all of the blues we can see. YlnMn Blue (so named because it results from a heating a combination of yttrium, indium, and manganese) was just discovered in 2009, and consequently added to the Crayola color palette.

Blue and we have quite the history, and who knows what our future with blue holds? It’s a pretty queer color though, so even though it showed up late to the party, we can all rest azured, it’s here to stay.

for further reading, we highly recommend MyModernMet's fascinating history of the shades of blue.
https://mymodernmet.com/shades-of-blue-color-history/

let's give credit, where credit is blue (significant sources):
MyModernMet
Medium
University of Adelaide
AllAboutVision
BusinessInsider Australia