Tyrian Purple

What color is Tyrian purple?

The story of Tyrian purple

Tyrian purple is the color of emperors, and it was made by leaving heaps of sea snails to rot in the sun.

The snails are murex, rock snails of the Mediterranean. Bolinus brandaris, the spiny dye-murex, gives a red-purple; Hexaplex trunculus, the banded one, gives a bluer shade. The Phoenicians of Sidon and Tyre, the port the dye is named for, built the industry by 1200 BC. The arithmetic is brutal: about 12,000 snails for 1.4 grams of dye, enough to trim one garment, and in the fourth century BC the dye sold for its weight in silver. The oldest surviving dyed fibers, found in Israel's Timna Valley in 2021, are about 3,000 years old.

Pliny the Elder wrote down the method. Take the snails after the rising of the Dog Star, extract the vein, salt it, steep it for three days, simmer it, and on about the tenth day test the liquor with a fleece. He rated the blackish result above the red. At the Phoenician works the snails were piled into vats to decompose, an Egyptian papyrus says the dyer's hands reek like rotting fish, and the Talmud let a woman divorce a husband who took up dyeing after the wedding.

Rome turned the smell into law. A magistrate wore the toga praetexta, white with a purple border; a general in his triumph wore the toga picta, solid purple with gold. By the fourth century AD only the emperor could wear it, so that to don the purple meant to take the throne, and selling the cloth became a state monopoly with the death penalty attached. Counterfeits ran on cheaper stuff, often indigo, and that was punished too.

Constantinople kept the vats going for another thousand years. The court paid for the dye works, and from the ninth century a child born to a reigning emperor was porphyrogennetos, born in the purple, after a room in the Great Palace lined with purple porphyry stone where empresses gave birth. Then the Fourth Crusade sacked the city in 1204 and imperial production never recovered; when the Ottomans took Constantinople in 1453 the color lost its throne for good. Europe's kings switched to scarlet from the kermes insect, and the method for making purple in quantity was forgotten.

Chemistry caught up in 1909, when Paul Friedlander showed that the dye is 6,6'-dibromoindigo: an indigo molecule wearing two bromine atoms, which is why the trunculus dye, left in sunlight before it sets, drops its bromine and turns the blue of jeans. It was first synthesized in 1914 and has never been made commercially. People revive it anyway: a working vat recipe was rediscovered in 1998 by trial and error from Pliny's notes. The snails, meanwhile, are still eaten in Spain and Portugal.

So what is in a tube called Tyrian purple? Not a snail. It is a costume: usually quinacridone violet or dioxazine, or a cool red and a blue premixed and given the old name. The real thing was a smell and a death sentence before it was a color, and the color itself, a dark wine red edging toward violet, takes ten seconds to mix from two pans. History has a sense of humor.

Pigment facts

These describe the pigment in general. Every brand's tube behaves a little differently, so test yours on scrap paper.

How to mix Tyrian purple

You can mix Tyrian purple in a breath. A cool red and a violet-blue: quinacridone rose or a permanent crimson with a little ultramarine, about three to one, gives the dark wine-red purple of the dye. Push toward the blue for the shade Hexaplex trunculus gave, toward the red for Bolinus brandaris. For Pliny's blackish shade, add a speck of indigo rather than black, which kills the glow.

Green Gold, its opposite, is the pairing that matters. A touch turns Tyrian purple into a warm shadow gray no tube gray can match; a little more gives you the brown of old velvet.

Using Tyrian purple in watercolor

Use Tyrian purple where a red needs to go into shadow without turning brown: the underside of a plum, the dark half of a rose. It is also the color of evening clouds after the orange has gone.

Glazing is the technique. A thin pass of the mix over a dry Poppy Bloom red gives a shadow that still reads as the same object, where a gray glaze reads as dirt. Keep it thin and judge it dry.

Pair it with its opposites. Green Gold beside it looks greener and the purple looks deeper, and a Lemon Yellow highlight beside a Tyrian purple shadow makes a still life sit up.

One thing I learned the hard way: a purple mixed from a red and a blue goes chalky if you work it on the paper. Mix it fully on the palette, lay it once, and leave it. Every extra stroke pulls the two apart and the wash dries dull, like a week-old bruise.

Tyrian purple vs royal purple (and mauve)

Royal purple is what most people picture when they hear the name, and it is wrong. The color that took that name in English in 1661 is bluer than the ancient dye, a proper violet. Real Tyrian purple is a red: dark wine, closer to crimson than to violet, and the Romans filed it as a blood color.

Mauve is the color that ended purple's exclusivity. In 1856 William Henry Perkin, eighteen years old, was trying to make artificial quinine and found a purple residue instead, the first aniline dye. Queen Victoria wore it in silk in 1862, and by 1890 it was everywhere. Cheap purple for everyone, from a coal-tar accident, three thousand years after the Phoenicians.

If Tyrian purple is a cardinal's cloak, royal purple is the stage costume of one, and mauve is the day the cloak went on sale.

More color stories

Mel, founder of Tobio'sI make portable watercolor kits and I named the company after my cat. I write these pages for the beginner I used to be, one pigment at a time.