Colour & Colour Management — 60 Terms Defined

Display P3 Colour & Colour Management A wide colour space now standard on modern phones, tablets and laptops, combining the DCI-P3 primaries with sRGB's white point and transfer curve.

Gamma Colour & Colour Management γ exponent The non-linear relationship between stored numerical values and displayed brightness in a colour space or on a device. Output = Input^γ

Gamut Colour & Colour Management The complete range of colours a device, medium or colour space can produce or record.

Gamut Mapping Colour & Colour Management The process of converting colours from a larger space into a smaller one while preserving as much of the image's appearance as possible.

HSL Colour & Colour Management A colour model describing colour by hue, saturation and lightness, widely used for targeted colour editing.

Hue Colour & Colour Management degrees (0-360) The attribute of a colour that gives it its name — red, green, blue — represented as a position on a circular scale.

ICC Profile Colour & Colour Management A standardised data file describing how a device's colour numbers relate to absolute, measurable colour.

Kelvin Scale Colour & Colour Management K The absolute temperature scale used to state the colour of light sources and white balance settings. K = °C + 273.15

Lightness Colour & Colour Management L* The perceived brightness of a colour on a scale from black to white, independent of its hue and chroma. L* = 0 (black) to 100 (white)

Look-up Table (LUT) Colour & Colour Management A table mapping input colour values to output values, used to apply a colour transformation quickly and repeatably.

Metamerism Colour & Colour Management The phenomenon in which two samples match under one light source but differ visibly under another.

Mired Colour & Colour Management mired A unit of reciprocal colour temperature that makes colour shifts uniform in perceptual terms, used to specify filters and gels. mired = 1,000,000 / K

Mixed Lighting Colour & Colour Management K A scene illuminated by two or more sources of different colour temperature, which cannot all be neutralised at once.

Monitor Calibration Colour & Colour Management K, cd/m², gamma Measuring a display with an instrument and building a profile so its output matches known standards for white point, brightness and tone response.

Out-of-gamut Colour Colour & Colour Management A colour present in an image that the destination device or space cannot reproduce.

Perceptual Rendering Intent Colour & Colour Management A conversion strategy that compresses the entire colour range so relationships between colours are preserved, at the cost of shifting every colour slightly.

ProPhoto RGB Colour & Colour Management A very wide colour space that encompasses almost all colours a camera can capture, including some outside human vision.

Rec. 2020 Colour & Colour Management The very wide colour space defined for ultra-high-definition television and high dynamic range delivery.

Rec. 709 Colour & Colour Management The colour space and transfer function standard for high-definition television, sharing its primaries with sRGB.

Relative Colorimetric Intent Colour & Colour Management A conversion strategy that reproduces in-gamut colours exactly and clips out-of-gamut ones to the nearest reproducible value.

Rendering Intent Colour & Colour Management The strategy chosen for handling colours that fall outside the destination gamut during a colour space conversion.

Saturation Colour & Colour Management % The intensity or purity of a colour, from fully neutral grey to the most vivid version available.

Selective Colour Colour & Colour Management An adjustment that targets one range of colours in an image while leaving the rest unchanged.

Spectral Power Distribution Colour & Colour Management W/nm A plot of how much energy a light source emits at each wavelength across the visible spectrum.