I place a delphinium, Blue, upon your grave.

                        —Derek Jarman

The world I'm looking at is blue, faintly blue. I'm gazing out the window of the Better Living Through Coffee Coffeehouse in Port Townsend, Washington, taking in a view of Admiralty Inlet. I sip a double-short latte and look out. Water. Distant mountains. A long dock, and, out in the inlet, a dolphin (a cluster of pilings) to guide the ferry arriving from Whidbey Island. A heap of rocks edging a stony gray beach appear to be part of a retaining wall. The sky and water are bright and dark, tinted gray and blue. The mountains stand in a blue haze.

***

For days I've been attempting to see the color blue as the ancient Greeks might have seen it. They had no word for blue. Homer never mentions the color blue. In The Odyssey, you have the "wine-dark sea." Wine-dark? But Homer, whoever he was, may have been blind. Still, The Odyssey and The Iliad emerged from a much older oral tradition. No blue. Does this mean the ancient Greeks could not actually see blue? Is this even possible? What of the vivid blue sky over the Mediterranean?

***

Many languages did not and some still do not include the color word blue. Color words tend to enter languages in the order of black and white (or dark and light), and next red, and next green and yellow, colors that often share one and only one word, and finally blue. And consider this: We English speakers designate navy blue and sky blue as different shades of the same color, but in the light spectrum, sky blue's wave length is closer to green than it is to navy blue. Language colors color perception. And consider this: Language is a dunce in the face of the million or so colors we can actually see.

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Seriously, how much blue is there in the natural world? If you eliminate modern synthetic dyes, which came into existence with the invention of mauve from coal tar by William Perkin in 1856, how much blue do we blue-seeing people see? On the ferry from Seattle to Port Townsend, I noted that Puget Sound's rough waves took on a metallic-looking dark green. I dub it steel-green. No way could you call blue that long arm of the sea that is Puget Sound. Could it be, asks linguist and color researcher Guy Deutscher in his book Through the Language Glass, that calling the sky "blue" is a cultural convention?

***

Here's a story told on the renowned Radiolab podcast on color.

Psychologist Jules Davidoff studied the Himba people from Namibia. This cattle-herding people make no distinction between green and blue, and have no word for blue. Davidoff showed tribal members a circle of twelve squares of which eleven were bright green and one was bright blue. Could they see the blue? Not really. They deliberated for a long time before deciding and made frequent mistakes. But the Himba have color words we don't have. You can find on the Internet the two tests, including one with eleven green squares and one square the color of a Himba color word. I can, just barely, after much squinting, see that there is something different about one of the squares, but I can't really see what. Looks kind of off-green to me.

***

And here's another story told on that same Radiolab podcast. The abovementioned Guy Deutscher has a daughter, Alma. Due to his great interest in language and color perception, he taught his toddler girl every color. What color is this? Boo! she would say (Blue!). He and his wife agreed that they would never say "blue sky" in front of her; indeed, they would never mention the color of the sky. So one day, after Alma had every color down without a second's hesitation, father and daughter were out walking on one of those intensely blue-sky days and he was pointing to things and asking what color this or that was and his child answered enthusiastically and with unfailing correctness. Then he looked up at the sky and asked her what color (very blue) it was. She looked up. A look of utter incomprehension came over her face. She had no idea. In the following days he would ask her again, and she wouldn't know or she would guess "white," and eventually "blue" but then change her mind. At age 4 she once pointed to a pitch-black night sky and declared that it was "blue!"

***

The water-sky world seen through this coffeehouse window—accompanied by the voice of Billie Holiday singing the blues—is largely gray. The espresso machine hisses and people at other tables are loudly laughing and talking—odd for 7:30 a.m. on an Easter Sunday morning. Yes, the palest blue streak shows through the white-gray cloud cover. Blue tints ripples in the water that are mostly dark (almost black) and light (white).  Am I thinking blue because the words blue and sky seem to fit together, because in storybooks anyhow it's "the deep blue sea"?

***

I am writing this in a Mead composition book whose pages are ruled with pale blue lines. On my hand holding down the page is a lapis lazuli ring—its flat stone set in silver wire. This blue stone gives me a connection to the old matter of blue pigment. From the sixth to the twelfth centuries, lapis lazuli was ground to get blue for use in Byzantine manuscripts. In the sixth and seventh centuries—very late in terms of Homer et al., not at all ancient—it was ground to get blue for wall paintings in Afghanistan. And in the eleventh century it was ground to get blue for use in paintings in India and in China. In the words of Philip Ball in Bright Earth, a history of the chemistry of artist's pigments, this blue gotten from lapis lazuli was "not grand."

Lapis lazuli is not pure blue. Crushed, its non-blue components weaken its blue hue. Its blue is provided by the mineral lazurite, a compound composed of aluminum, silicon, oxygen, and sulfur. To get the blue lazurite out of dull powdered lapis lazuli was beyond technological ken until, in medieval times, the recipe was concocted, likely in Afghanistan. It required powdering the rock, mixing it with resin, gum, and lye, and cooking it and pouring it, repeatedly. The costly, precious blue lazurite, renamed ultramarine, was thereafter used in many paintings, most notably in the robe of the Virgin Mary. In Vermeer's The Milkmaid (1658), the gorgeous blue in the milkmaid's garment is ultramarine.

***

But ultramarine blue is not a feeling-blue blue. Ultramarine is bright, pulsing, dazzling. To feel blue is to feel down, low, melancholic.

The blues—the Muddy Waters, Mose Allison, Mississippi John Hurt type of blues—got their name, it seems, because the blues cures the blues. According to the Oxford English Dictionary, in 1915 the Chicago Tribune reported: "That is what ‘blue’ music is doing for everybody—taking away what its name implies, the blues." But why is a blue mood blue? Why not yellow (that sunny color) or green? The use of blue for melancholy is old. In 1450 we read in Chaucer: With teres blewe and with a wondyd herte Taketh youre leue. (With tears blue and with a wounded heart take your leave.)

***

I used to get the blues in a big way, perhaps once every three or four years. The depression would last a few weeks. This was back in the Boston years when I was in my twenties and thirties. I haven't felt so down in a long time. Age flattens emotions. Now I miss feeling blue. Nostalgic for the bad old days? Maybe. Being blue slows you down. You don't run around or move fast. You are not in a party mood or a chatty mood or a cheerful mood. You don't answer the phone. Chatty, cheerful people annoy you. This low-down blue mood is reflective, contemplative, an actual comfort. Or maybe I'm remembering it nostalgically, i.e., falsely.

***

Picasso rendered his renowned Blue Period paintings, not in dazzling ultramarine, but in Prussian blue. A sadder blue. Prussian Blue was invented during a chemical mixup by a "colormaker," named Diesbach in 1704 or 1705. He was attempting to make red, his ingredients became contaminated, and Prussian blue (iron ferrocyanide) materialized.

Picasso painted his Blue Period paintings between 1901 and 1904. He was out of luck. Out of funds. Feeling blue. A close friend, Carlos Casagemas, had just committed suicide. Picasso was failing to support himself and for a time was obliged to return from Paris, where he'd moved at age 19, to Barcelona to live in his childhood home with his parents. Humiliating. And the Blue Period paintings were depressing. No one wanted them—at the time. So his penury went unrelieved.

Some Blue Period paintings, as Picasso's biographer John Richardson puts it, are sentimental and a bit maudlin. Others, Richardson says, "have a solemn presence and an air of compassion." Picasso's Blue Period paintings were among my first art loves, especially The Old Guitarist (1903–1904), The Tragedy (1903), and Blue Nude (1902). I discovered them back when I was 15, living at my grandmother's house in Bucks County, Pennsylvania, perusing the art books in that well-kept home, priding myself on learning about art. I still like them.

***

Where do we see the color blue? Bluebirds are blue. Kingfishers. The steller's jays that visit my Seattle yard glint neon blue. The Douglas asters blooming in my yard have pale blue petals and yellow centers. Pennsylvania bluestone is more gray than blue. The veins of people with pale white skin show through as blue, and this is the origin of the term blue blooded.

***

Blue jeans are blue. Blue as indigo, the vegetable dye that originally blued denim. Indigo is an ancient blue derived from tropical plants in the genus Indigofera. As far back as 2500 BCE, Egyptians wrapped their mummies in indigo-dyed cloth. A tablet from ancient Babylonia contains a recipe for indigo dye. In West Africa women were its master dyers and master traders. In the 1500s and 1600s Europe resisted indigo, demonized it, deemed it toxic, magic, a pathogen leading to sexual impotence. No wonder, since indigo threatened the woad trade. Woad, "indigo's inferior cousin" in the words of James Sullivan in his book Jeans, is another vegetable dye (Isatis tinctoria). Woe to woad. Indigo won. It became part of the slave trade and flourished in colonial South Carolina. By 1755 the colony was exporting five hundred tons of indigo annually. Indigo was also big in India. India had its Blue Mutiny, a peasant revolt in 1860 when it was made illegal to plant rice where indigo had ever grown. Indigo made further history in 1917 when Mahatma Gandhi staged his first act of civil disobedience in Bihar in solidarity with indigo growers.

Back to blue jeans. Back to denim, a cotton weave, a "warp-faced twill." On the loom the warp (vertical threads) are dyed indigo, the weft (horizontal threads) are left undyed, white. Denim is a twill, that is, the weft is woven under two blue warp threads, then over one, then under two. This makes the blue face out, creating this warp-faced twill. Blue jeans are more blue than white but the more they wear the more they whiten.

Levi Straus did not invent denim. "Blue collar" workers had long worn it in aprons and work trousers. He did not invent blue jeans, though he did make millions off them. He emigrated from Bavaria with his mother and two sisters in 1847. He was 18 years old. His two half-brothers had a mercantile store in Manhattan. By 1853 he was in California, where the gold rush had cranked up the market for work pants. But here, writes James Sullivan in Jeans: The Story of an American Icon, the stories become apocryphal, various imagined scenarios assisted by the 1906 San Francisco fire, which destroyed not only the city but most of its records. The riveted pants, the pants with pockets reinforced with copper rivets, was the invention of a struggling tailor, Jacob Davis, who lived and worked in Reno, Nevada, and bought his denim from Levis Strauss. Davis's riveted trousers became so popular that he thought it would be a good idea to patent them, but he couldn't afford to do it. He joined forces with Levi Straus, who in 1873 patented the pants, and the rest is history—embroidered with hearsay.

***

For seventy minutes Derek Jarman's film Blue holds to one image, an image that fills the screen, an image of blue. It is a deep, vivid blue, the blue invented by the French painter Yves Klein in 1960 or thereabouts. Blue is Jarman's last film. He was a painter as well as a filmmaker. He was a master gardener. A gay rights activist. He died of complications of AIDS on February 19, 1994.

Blue is a memento of images lost, last words. The fathomless blue of bliss. I expected it to be "experimental" in some clever way, in other words, irritating. No. It is profoundly moving. The script (I couldn't hear it well and turned on the subtitles, which undoubtedly compromised the vision of deep shimmering blue): I resign myself to fate. Blind fate. Named are friends dead of AIDS. Named are the drugs. The hospital room. Hell on Earth is a waiting room. And the passage: Kiss me again. Kiss me. And again. Never enough.

Going blind, dying of AIDS, Derek Jarman wrote:

Blue protects white from innocence

Blue drags black with it.

Blue is darkness made visible.