Bullfight

It’s commonly believed that red capes make bulls angry. But actually, bulls are colorblind — and cannot see the color red at all! It’s the movement of the cape that provokes the bull, and the cape is red to camouflage bloodstains.

Louis’ Legs

King Louis XIV liked to show a little leg. “He was known as having gorgeous legs and he wore all kinds of fashion that would show them off,” explains French history expert Joan DeJean. And what better way to show off your legs than heels? Under his knee-length tight pants and silk stockings, Louis wore scarlet red heels.

Red Tape

“Red tape” goes back to the 1700s. Though back then it wasn’t sticky tape, but red ribbons used to bind documents. Red dye was expensive and “symbolized royal power and wealth,” Del Dickson explains in The People’s Government. Later, red tape came to symbolize annoying bureaucratic obstacles.

Attraction

If your idea of a fun night out involves getting a few new numbers, you might consider wearing red: Studies find both men and women see the other sex as more attractive when wearing red. Other studies found that women perceive other women wearing red as sexual threats, and men give better tips to waitresses wearing red shirts.

Rhymes With …

Need a rhyme for orange? Poets of the world, we’ve got you covered: Blorenge is a large hill in Wales.

You’re welcome.

Diet

Did anyone tell you when you were a kid that too many carrot sticks would turn your skin orange? It’s true! (Sort of). Hypercarotenemia, or carotenosis, is a yellowy orange discoloration of the skin caused by high levels of carotene in the blood, the result of eating a LOT of vitamin A.

Brown

We often think of brown as its own color, but according to Jude Stewart’s Roy G. Biv, it’s “actually a low-intensity shade of orange.”

Architecture

Though many people think of San Francisco’s Golden Gate bridge as red, it’s actually painted a special shade of “international orange.”

Food Coloring

When NPR’s Ari Shapiro encountered some “ghostly pale” egg yolks abroad, he turned to NPR’s food blog for answers: “Egg yolk color is almost entirely influenced by the birds’ diet. So if you’re feeding birds yellow corn, ‘it gets in the egg,’ [Kansas poultry specialist Scott Beyer] explains.”

Mystery solved.

Pee Paint

Until the late 1800s, Indian Yellow (a popular painter’s pigment) was made from cow urine. Specifically from “the urine crystals of cows fed entirely mango leaves, a diet that rendered cattle haggard (and farmers poor),” Stewart writes in Roy G. Biv. Fortunately for artists and cows alike, a method was eventually developed to make the pigment synthetically.

History

In the early 20th century, chaos reigned when it came to school bus colors. They were green, blue and even white. Then, in 1939, an education professor organized a conference to set the first school bus safety standards. There, he proposed 50 shades of yellow, which were eventually narrowed down to the cheerful hue we see today.

Etymology

“Pink” once meant “yellow.” What? We know, it’s confusing. See, Dutch “pink” was a yellow pigment; but because “pink” also means a frilled edge, it became closely associated with the dianthus flower, which has notched petals. And what’s the most common color for dianthus flowers? You guessed it: pink. Still confused? We are, too.

Eeexcellent

Simpsons creator Matt Groening explains why he made the show’s characters yellow: “I didn’t want the conventional cartoon colors. An animator came up with the Simpsons‘ yellow and as soon as she showed it to me I said: ‘This is the answer!’ because when you’re flicking through channels with your remote control, and a flash of yellow goes by, you’ll know you’re watching The Simpsons.”

NASCAR

Green is often associated with good luck, but not for NASCAR drivers. Ever since Indianapolis 500 winner Gaston Chevrolet was killed in a green car in 1920, green race cars have been seen as a bad omen.

Wicked

In the course of filming The Wizard of Oz, actress Margaret Hamilton’s skin started turning green from the face paint she wore as Wicked Witch of the West. “I suppose the stuff gradually sort of sunk into my skin,” she told author Aljean Harmetz. “It must have been months before my face was really normal again.”

Dress Code

Gentlemen, think twice before you wear a green hat in China. The Chinese expression “to wear a green hat” refers to a man who’s been cheated on. (A few foreigners have learned this the hard way.)

Poison

For thousands of years, green was a tricky pigment to nail down, but the 19th century saw the rise of two stable and incredibly popular green dyes. There was just one problem: Both were laced with arsenic. At the time, the health risks of arsenic exposure were unknown, but before long, doctors and newspapers began attributing illnesses to green-wallpapered rooms. (There’s even a theory that arsenic-laced wallpaper helped do in Napoleon.)

Linguistics

In language, blue tends to be the last color word developed across cultures, as linguist Guy Deutscher explains on Radiolab. The first is red. One theory is that blue is one of the hardest color dyes to make, and red is the easiest.

Favorites

If blue is your favorite color, you’re not alone. A 2007 study found that people tend to prefer blue over other colors. Why? Researcher Anya C. Hurlbert suspects it might be evolutionary: Back in our “savannah days,” clear blue would have signaled good weather and clean water.

Perception

The most brilliantly blue things, like a peacock feather or even a human blue eye, don’t have a single bit of blue pigment in them. “Blue is fascinating because the vast majority of animals are incapable of making it with pigments,” says evolutionary biologist Rick Prum. Instead, many have developed structures on their surface that bounce light in just the right way to make them appear bright blue to the viewer.

Eye Candy

Only 1 out of every 6 Americans has blue eyes, and 1 out of every 2 Americans will tell you that blue eyes are the prettiest, The New York Times reports. In fact, half of all tinted contact lenses sold are designed to make brown eyes look blue.

Newton’s Fault

Isn’t indigo basically blue? Why is it even in Roy G. Biv? We have Isaac Newton to thank for this one: He wanted the number of colors in the spectrum to match Rene Descartes’ seven-tone musical scale, and indigo brought the color count to seven.

Indiglow

Ripe bananas glow bright indigo under black light. Researchers attribute it to the unique way bananas break down chlorophyll as they ripen and theorize that it may come in handy for banana-eating animals that see in the UV range, like fruit bats.

History

The flag that inspired Francis Scott Key’s “Star-Spangled Banner” in 1814 had a blue star field that was dyed with indigo.

Pop Culture

Just as arbitrary as indigo is the way The Indigo Girls named their band: “We needed a name, and so we went through the dictionary and looked for words that struck us, and that was one,” band member Amy Ray told NPR. “You know, we were like 20 years old, I guess.”

Conchology

Making purple wasn’t easy in ancient Rome. In a complicated and smelly process, thousands of marine snails — which aren’t actually purple themselves — were boiled for days in enormous vats.

Chemistry

In 1856, while looking for a cure for malaria, chemist William Perkin stumbled upon the first synthetic dye. He was trying to make quinine in a lab but ended up creating a purple liquid that came to be known as mauveine or aniline purple. (Unfortunately, it did not cure malaria. But at least it wasn’t snails?)

Protest

Police sometimes use water cannons filled with purple dye to spray protesters, to identify them later. In 1989, anti-apartheid protesters in South Africa managed to redirect one of these cannons and turn the ruling party’s headquarters purple, inspiring the anti-apartheid slogan “The Purple Shall Govern.”

Society

When I am an old woman I shall wear purple
With a red hat that doesn’t go and doesn’t suit me.

Those first few lines of Jenny Joseph’s poem “Warning” inspired a global society of (mostly) older women who wear purple outfits and red hats. (You don’t have to be over 50 to join the Red Hat Society, but younger members wear lavender outfits with pink hats).