What colour am I?

Decides fast, moves first, apologises later.

Red is the oldest pigment in human art, and the only colour with a dedicated word in every language that has more than two colour terms. It carries the widest split in meaning of any hue: luck and celebration across much of East Asia, danger and prohibition in most road-sign systems, love and appetite in Western advertising. Physiologically it is the colour the eye locates fastest against green foliage, which is probably why it ended up on stop signs and fire engines rather than anything symbolic.

Turns a room up two notches without trying.

Orange is the newest of the common colour words in English: the fruit came first, arriving from Sanskrit through Persian and Arabic, and the colour borrowed its name around 1500. Before that the hue was simply called yellow-red. It reads as warmth and cheapness at once in Western marketing, which is why budget airlines and discount chains reach for it, and it carries sacred weight in Hinduism and Buddhism, where saffron robes mark renunciation.

Assumes it will probably work out, and is often right.

Yellow is the most visible colour to the human eye in daylight, which is why it took over from red on hazard markings, school buses, and high-visibility clothing during the twentieth century. Its symbolism is unusually split: joy and sunlight in most of the world, cowardice in English idiom, imperial authority in historic China where commoners were barred from wearing it, and mourning in parts of Latin America.

The one everything else gets built on.

Green sits at the centre of human colour sensitivity: the medium-wavelength cone peaks near it, and we can distinguish more shades of green than of any other hue, which is usually explained as an adaptation to reading foliage. Its associations are unusually consistent worldwide, covering growth, health, and permission, though English also keeps green for envy and for inexperience.

Calm in the way that is actually calm, not suppressed.

Teal takes its name from the duck, whose eye stripe is exactly this colour. It sits between blue and green on the wheel, in the region where languages most often disagree about where one colour ends and the next begins. Japanese famously used a single word, ao, across a range covering both, and traces of that survive in why Japanese traffic lights are noticeably more blue than elsewhere.

Trusted by default, which is a heavier job than it sounds.

Blue is the most commonly named favourite colour worldwide and the last major colour word to appear in most languages, showing up only after black, white, red, and yellow. Homer never uses it. The reason is likely economic rather than perceptual: blue pigment was hard to make and rare in nature, so cultures had little reason to name what they could not produce.

Wants the underlying reason, not the working answer.

Indigo is the odd one out in Newton's spectrum: he wanted seven colours to match the seven notes of a musical scale, so he split the blue-violet region in two. Most people cannot reliably pick indigo out of a spectrum as its own band, and modern colour science generally treats it as a shade of blue. The dye itself, from Indigofera, was one of the most valuable trade goods of the early modern world.

Would rather be interesting than correct.

Tyrian purple was made from the mucus of the murex sea snail, and it took roughly 250,000 of them to dye a single robe. That cost, not any inherent quality of the hue, is the entire reason purple means royalty: Roman sumptuary law eventually restricted it to the emperor. The association survived the invention of cheap synthetic mauve in 1856, which is a good illustration of how durable colour symbolism is once it sets.

Reads the room before anyone has said anything.

Pink was considered the masculine colour in Western children's clothing well into the twentieth century, on the logic that it was a diluted red and therefore martial, with blue assigned to girls as the gentler shade. The modern convention only settled after the Second World War. Pink is also perceptually odd: unlike most colours it has no single wavelength, existing only as a mixture of red and blue light.

Practical, unhurried, allergic to nonsense.

Terracotta is literally baked earth, and the pigment family behind it, the iron oxides, is the oldest in human use: the ochres in the Blombos Cave workshop in South Africa are around 100,000 years old. Every culture that has ever painted anything has had access to this colour, which makes it the least symbolically loaded hue on the wheel and the most consistently associated with the ground itself.

Says less than they know, on purpose.

Grey is the only common colour word in English with two accepted spellings split by geography, grey in Britain and gray in the United States, both from the same Old English graeg. Visually it is the colour of pure lightness with no hue at all, which is why it functions as the reference in photography: an 18 percent grey card reflects a fixed share of the light falling on it, giving a camera something honest to meter against.

Removes rather than adds, in most things.

Black absorbs across the visible spectrum rather than reflecting a band of it, which is why the darkest engineered materials work by trapping light in a forest of carbon nanotubes rather than by pigment. Culturally it inverted: it was the colour of mourning in Rome, then of piety and then of wealth in Renaissance Europe once a truly deep black dye became expensive to produce, and it has held the formal-wear slot ever since.