Earth, a pale blue dot seen just past the rings of Saturn, taken by the Cassini spacecraft on July 19, 2013.
We can explain the wan blueness of this little world because we know it well. Whether an alien scientist newly arrived at the outskirts of our solar system could reliably deduce oceans and clouds and a thickish atmosphere is less certain. Neptune, for instance, is blue, but chiefly for different reasons. From this distant vantage point, the Earth might not seem of any particular interest.
But for us, it’s different. Look again at that dot. That’s here. That’s home. That’s us. On it, everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every “superstar,” every “supreme leader,” every saint and sinner in the history of our species lived there-on a mote of dust suspended in a sunbeam.
The word itself has another color. It’s not a word with any resonance, although the e was once pronounced. There is only the bump now between b and l, the relief at the end, the whew. It hasn’t the sly turn which crimson takes halfway through, yellow’s deceptive jelly, or the rolled-down sound in brown. It hasn’t violet’s rapid sexual shudder or like a rough road the irregularity of ultramarine, the low puddle in mauve like a pancake covered in cream, the disapproving purse to pink, the assertive brevity of red, the whine of green.
How do you know, when you think blue— when you say blue— that you are talking about the same blue as anyone else?
You cannot get a grip on blue.
Blue is the sky, the sea, a god’s eye, a devil’s tail, a birth, a strangulation, a virgin’s cloak, a monkey’s ass. It’s a butterfly, a bird, a spicy joke, the saddest song, the brightest day.
Blue is sly, slick, it slides into the room sideways, a slippery trickster.
This is a story about the color blue, and like blue, there’s nothing true about it. Blue is beauty, not truth. ‘True blue’ is a ruse, a rhyme; it’s there, then it’s not. Blue is a deeply sneaky color.
Scientific discovery and artistic innovation often occur together in unpredictable ways. How is this relationship shaped by accident and synchronicity?
During the early 1700s, the color maker Diesbach was attempting to produce a red pigment from iron sulfate and potash in his laboratory in Berlin. He decided to be frugal and use some contaminated potash which his friend, the alchemist, theologian, and physician Johann Konrad Dippel, widely purported to be the model for Dr. Frankenstein, was about to throw out. As a result, he first obtained a very pale and unsatisfactory red. He decided to concentrate it, but it turned purple instead of a deeper red. At this point he concentrated it one last time and it became deep blue. Diesbach had accidentally created the first synthetic blue paint.
Prussian blue thinned with turpentine
At that time the best and most reliable blue pigments came from ground lapis lazuli, a semi-precious stone, and they were extremely expensive. This alternative, easy to make, inexpensive, intense and non-toxic, would become incredibly popular and was known as Prussian or Berlin blue. It would later be used to color the uniforms of Prussian soldiers. In an ironic twist, painters also sometimes refer to it as Parisian blue, since the first painter to make it famous, although not the first to use it, was Antoine Watteau, who passed it on to his students. It has been used by artists all over the world, including Asian painters such as Katsushika Hokusai, who imported it from Europe. The color appeared in the crayon box in 1949 and has been known as Midnight Blue since 1958.
Great Wave off Kanagawa by Katsushika Hokusai
Prussian blue is made from a powder of tiny crystals. These crystals are not water soluble and differences in their size result in variations in shade. The color owes its intensity to the transfer of electrons between iron compounds. Unfortunately for us, Prussian blue cannot be accurately reproduced on a computer display.
In 1842, the scientist and astronomer Sir John Herschel, seeking a means to reproduce notes and diagrams, would use a solution of Prussian blue on treated paper. This was called a cyanotype, although we are more familiar with the term blueprint. He shared his invention with friends, including the botanist Anna Atkins. One of his first experiments was a rather eerie copy of an engraving of a lady playing the harp, seen below.
Lady with a Harp, Sir John Herschel, 1842
Anna, born in 1799, was the daughter of another famous scientist, John George Children, a mineralogist, zoologist and chemist. Her mother, Hester Anna, died from complications after Anna was born. As Children’s only child, she was very well educated and grew into a an accomplished scientist herself. Her father used her engravings to illustrate his translation of Lamarck’s Genera of Shells, published in 1823. After her marriage to John Pelly Atkins in 1825, she devoted herself to collecting plant specimens.
When Herschel exhibited the cyanotype as a way to copy manmade items, Atkins was intrigued and saw potential to render the images of natural subjects. She began making contact printed images of algae by placing them on cyanotype paper and exposing them to light, creating the photogram or camera-less photo.
Dictyota dichotoma, Photographs of British Algae: Cyanotype Impressions (1843) Anna Atkins
“The difficulty of making accurate drawings of objects as minute as many of the Algae and Confera, has induced me to avail myself of Sir John Herschel’s beautiful process of Cyanotype, to obtain impressions of the plants themselves.”
–Anna Atkins
Cystoseira granulata, Photographs of British Algae: Cyanotype Impressions (1843) Anna Atkins
In 1843 she published Photographs of British Algae: Cyanotype Impressions, the first book ever published containing photographs. She published a number of such books as well as non-photographic literary works, including her father’s memoirs, before she died at the age of seventy-two.
If a little kid ever asks you just why the sky is blue, you look him or her right in the eye and say, “It’s because of quantum effects involving Rayleigh scattering combined with a lack of violet photon receptors in our retinae.”
It suddenly struck me that that tiny pea, pretty and blue, was the Earth. I put up my thumb and shut one eye, and my thumb blotted out the planet Earth. I didn’t feel like a giant. I felt very, very small.
