75 colour-terminology terms, each defined once and linked to from tools, colour profiles, history and practical guidance rather than re-explained per page.
Hue
The base colour itself — red, blue, green, yellow and so on — independent of how light, dark or saturated it is.
Shade
A hue with black added — a darker version of the same colour.
Tint
A hue with white added — a lighter, softer version of the same colour.
Tone
A hue with grey added — a more muted, softer version of the same colour.
Saturation
How intense or how 'washed out' a colour looks — high saturation is vivid, low saturation is closer to grey.
Chroma
Similar to saturation — how far a colour is from neutral grey — but measured in a way that stays consistent across different lightness levels.
Value
How light or dark a colour is, on a scale from black to white, independent of hue.
Brightness
How much light an area appears to give out or reflect — in everyday use, also a loose word for both value and lightness.
Lightness
How close a colour is to white or black.
Undertone
A subtle warm or cool bias within a colour that otherwise reads as fairly neutral — a 'warm white' vs a 'cool white', for example.
Warm colour
A colour with a red, orange or yellow bias — associated with heat, sunlight and cosiness.
Cool colour
A colour with a green, blue or purple bias — associated with calm, shade and freshness.
Neutral colour
A colour with very little hue strength — greys, off-whites, beiges and similar low-saturation colours.
Pastel
A soft, pale colour that still has a hint of colour rather than reading as pure white.
Muted colour
A colour that has been softened toward grey — less intense than its purest, most vivid version.
Vivid colour
A strongly saturated, intense colour — the opposite of muted.
Complementary colours
Two colours from opposite sides of the colour wheel — a classic high-contrast pairing.
Analogous colours
Colours that sit next to each other on the colour wheel — a harmonious, low-contrast pairing.
Triadic colours
Three colours spaced evenly around the colour wheel.
Split-complementary colours
A base colour plus the two colours next to its complementary opposite, rather than the exact opposite itself.
Colour temperature
A measure of how warm (yellow/orange) or cool (blue-white) a light source looks, usually given in Kelvin.
CRI (Colour Rendering Index)
A score, with 100 as the maximum, for how accurately a light source shows colours compared with a reference light of the same colour temperature.
Metamerism
When two colours look like a matching pair under one light source but noticeably different under another.
Pigment
A finely ground, insoluble colouring material mixed into paint, ink or other media.
Dye
A soluble colouring material that chemically bonds with or is absorbed into the material it colours, such as fabric.
Structural colour
Colour produced by microscopic physical structures scattering or reflecting light, rather than by pigment.
Additive colour
Mixing coloured light, where combining colours moves toward white — how screens work.
Subtractive colour
Mixing pigments or inks, where combining colours moves toward black — how paint and print work.
Opacity
How much a material blocks light from passing through — fully opaque means no light gets through at all.
Translucency
Letting some light through while still scattering it, so objects behind aren't clearly visible — frosted glass is translucent, not transparent.
Iridescence
A shifting, rainbow-like colour effect that changes depending on the viewing angle.
Carotenoid
One of a family of yellow, orange and red pigments made by plants and algae: the colour of carrots, tomatoes, peppers, egg yolk, salmon and autumn leaves.
Anthocyanin
One of a family of water-soluble plant pigments that give red, purple and blue to berries, red cabbage, red grapes and many flowers, and that change colour with acidity.
Colour constancy
The human visual system's tendency to perceive an object's colour as relatively stable even when the lighting around it changes.
Apparent colour
The colour something looks like under specific, real viewing conditions, as opposed to a fixed, condition-independent value.
Simultaneous contrast
The way a colour's appearance shifts because of the colours around it: it looks lighter beside dark, darker beside light, and pushed away in hue from its neighbour.
Contrast ratio
A number from 1:1 to 21:1 describing how different two colours are in lightness, used to judge whether text and interface elements can be read.
Luminance
How bright light from a surface or screen is, weighted by the eye's sensitivity to each wavelength.
White balance
A camera setting (automatic or manual) that adjusts colours in a photo so that white objects actually look white under the light present at the time.
Melanin
A natural pigment responsible for the colour of skin, hair and eyes in humans, ranging in amount and type between individuals.
Light scattering
The way light bounces off tiny particles or structures in a material, sometimes producing a visible colour without any pigment being present.
Colour space
A defined way of turning numbers into colours, so that the same numbers mean the same colour wherever they are used.
Gamut
The complete range of colours a particular device, ink set or colour space can produce or describe.
White point
The particular white a colour space, display or viewing condition treats as neutral.
CIELAB (L*a*b*)
A way of writing any colour as three numbers: L* for lightness, a* for green to red and b* for blue to yellow, designed so that equal distances look roughly equally different.
OKLCH
A way of writing colours as lightness, chroma and hue that tracks how different the colours look more evenly than HSL.
ICC profile
A small data file describing how a particular device or colour space reproduces colour, so software can convert colours between devices.
Rendering intent
The rule used to move colours that do not fit when converting from a larger gamut to a smaller one.
Process colour (CMYK)
Printing colour built from dots of cyan, magenta, yellow and black ink, rather than a separately mixed ink for each colour.
Spot colour
A colour printed with its own pre-mixed ink instead of being built from CMYK dots.
Log encoding
A way of recording camera images in which each doubling of scene brightness takes about the same step of signal, so a very wide brightness range fits in the file; the footage looks flat until it is converted for a display.
Scene-referred colour
Image values that describe the light that was in front of the camera, as opposed to display-referred values, which describe the light a particular kind of screen should emit.
LUT (lookup table)
A stored colour transform: a table that gives an output colour value for each input value, used in film and video to convert between encodings or to apply a look.
Illuminant
A light defined by its spectrum on paper, so that colour calculations can say exactly which light they assume.
Spectral power distribution
How much energy a light gives out at each wavelength — the light's full recipe, of which its colour temperature is only a summary.
Reflectance
The share of light a surface sends back, measured wavelength by wavelength.
Transmittance
The share of light that passes through a material, measured wavelength by wavelength.
Absorbance
A logarithmic measure of how much light a sample stops: 0 means all of it passes, 1 means a tenth passes, 2 means a hundredth.
Light reflectance value (LRV)
A 0–100 figure for how much visible light a paint or surface reflects, used in decorating and building design.
ΔE (Delta E)
A single number for how different two colours are.
Spectrophotometer
An instrument that measures a surface's reflectance at many wavelengths, from which its colour under any light can be calculated.
Colorimeter
An instrument that measures colour directly as three numbers through filters that imitate the eye.
Fluorescence
When a material absorbs light, usually ultraviolet or blue, and gives it back out at a longer, visible wavelength.
Master standard
The approved physical sample that defines a production colour, kept in store and almost never handled; working standards are duplicates of it used for everyday comparison.
Gloss
How much light a surface reflects like a mirror rather than scattering it, from flat matt to high gloss.
Goniochromism
Colour that changes with the angle you view or light it from, as on metallic car paint, pearlescent finishes and some bird feathers.
Subsurface scattering
Light entering a surface, bouncing around inside it and coming out somewhere else — the reason marble, skin, wax and milk look soft and glowing.
Patina
The coloured surface layer a material develops as it ages — the green on old copper, the brown on bronze, the soft grey of weathered timber.
Efflorescence
A white, powdery deposit of salts that appears on brick, concrete, stone or plaster when water carries dissolved salts to the surface and evaporates.
Anodising
An electrochemical process that thickens the oxide layer on aluminium, which can then be coloured with dyes or metal salts and sealed.
Lightfastness
How well a colourant resists fading or changing when exposed to light.
Limewash
A traditional wall coating made from lime and water, white unless an earth pigment is added, brushed on in thin coats that have to be renewed.
Chromatophore
A pigment-containing cell, or in octopus, squid and cuttlefish a small organ, that an animal uses to change the colour of its skin quickly and reversibly.
Aposematism
Warning coloration: a conspicuous appearance carried by an animal that is costly to attack because it is toxic, distasteful or armed.
Photonic crystal
A material whose internal structure repeats at about the scale of light's wavelength, so that it reflects some colours strongly without containing any pigment of that colour.