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Articles on colour management can often contain unfamiliar jargon. Below you’ll find definitions of most terms that you’ll see.

 

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
 

A

Absolute Colorimetric

Rendering intent usually used in proofing to simulate the reproduction of a printing stock on an inkjet paper. Can also be used for colour evaluation and for softproofing on a monitor. Not usually used to convert images.

 

B

Black Point Compensation

Originally only in Adobe application but now becoming more popular in other software black point compensation maps the darkest neutral colour from a source profile to the darkest neutral in the destination profile. Generally produces better image conversions.

 

C

Calibration

Changing the behaviour of a device to conform to a standard or norm. Often a precursor to profiling a device and can be used to maintain colour consistency over time.

 

Candela

A unit of luminous intensity, usually candelas per meter squared - cd/m2.

 

Characterisation

Also known as profiling - measuring the colour behaviour of a device.

 

Chroma

Saturation level of a colour.

 

CIE

Commission Internationale d’Éclairage (International Commission on Illumination) - an international body of colour scientists who come up with many of the standards used in colour management.

 

CMYK

Often referred to as process colour or four colour - refers to the four inks used in some colour printing: cyan, magenta, yellow and key (black).

 

Colorant

Usually dyes, inks, toners, etc. Something that makes a colour on something else - paper, cloth etc.

 

Colour Model

A system for defining colour as a series of numeric values - for example RGB, CMYK or Lab.

 

Colour Space

The range colour achievable of a particular individual monitor, printer, scanner etc. Often used interchangeably with the term gamut and in some cases even with the term profile.

 

Colour Temperature

The colour of the light emitted by an object. Higher colour temperatures are blueish and lower ones more yellow. Measured in Kelvin (K) after Lord Kelvin who heated blocks of carbon to different temperatures to see what colour light they emitted.

 

Colorimeter

A device used for measuring colours, usually on monitors.

 

ColorSync

Apple’s software for handling colour management, it is embedded in the Mac operating system.

 

CRT

Cathode Ray Tube - old technology for monitors and TVs. Now replaced by LCD.

 

D

D50

A CIE standard illuminant with a colour temperature of 5000K and an even spectral distribution. Warmer than D65 and used in viewing booths in the printing industry.

 

D65

A CIE standard illuminant with a colour temperature of 6500K and an even spectral distribution. A cooler standard than D50. Often 6500K is the whitepoint used as the target for monitor calibration.

 

Delta E

A measurement of the colour difference between two colours. Often used to evaluate profiles and conversions. Lower Delta Es are better. Less than 1 is an almost perfect match.

 

DPI

Dots per inch - how we refer to the resolution of printers.

 

Dye

A colorant that is soluble in water. Often fades over time.

 

Dynamic Range

The range from dark to light that a device can reproduce or that is present in an image.

 

E

Embedding a Profile

Saving an ICC profile within an image or document file, synonym for tagging or assigning a profile. Provides the colour meaning for the values in the file.

 

G

Gamma

The way a device reproduces tonal values. Higher gamma values could be said to have higher contrast and lower values less contrast. 2.2 is a common gamma used in colour spaces and when calibrating monitors.

 

Gamut

The range of colours and tones a device can reproduce. Gamut Compression is the conversion from one large colour to a smaller one. Gamut Mapping is how colour and tones are converted from one colour gamut to another.

 

Gray Balance

Neutral values within a colour space.

 

GSM

Standing for ‘Grams per Square Meter’, GSM refers to the weight. The higher the GSM, the heavier and thicker the paper. Papers with a large GSM are perfect for those who are serious about achieving exhibition quality results, such as for fine art and gallery prints.

 

H

Hue

A way we can characterise the colour of a colour, as opposed to it’s saturation or lightness.

 

I

ICC

International Color Consortium - a group of companies who formulate standards for colour management.

 

Illuminant

Light source.

 

IT8

A group of targets used in calibration and profiling. Often refers to a scanner target.

 

K

Kelvin

Unit of colour temperature in the context of colour management but more properly it is a general temperature scale used in science.

 

L

Lab

Also CIE Lab and L*a*b*. A colour space formulated by the CIE. L* denotes how light a colour is, a* how red or how green and b* how blue or how yellow. Used extensively in colour conversions and measurements by colour management systems.

LCD

Liquid Crystal Display - technology used by most monitors and TVs. There are three types of LCD panel - TN, VA and IPS. TN are the cheapest and the lowest in quality, VA panels are much better and have some benefits over IPS panels but generally IPS panels are considered the best.

 

LED

Light Emitting Diode. Monitors now have backlight comprised of LEDs.

 

Luminance

Basically how bright a light source is. Usually measured in Candelas

 

LUT

Look Up Table - a table of values that allow referencing and replacement. Monitor calibration and profiling applications may adjust the LUT of a graphics card.

M

Metamerism

The property of two objects or colours to appear the same under one light source but different to each other under a different light source.

 

O

Optical Brightener

Chemicals used to enhance the whiteness of paper that fluoresce under UV light.

 

Output Profile

Usually profile for a printer, proofer or printing press but can be any profile used as a destination for a colour conversion.

 

P

PCS

Profile Connection Space - a colour space used in profile conversions as an intermediate step. Either XYZ or Lab are used in ICC colour management.

 

Perceptual

Rendering Intent that scales one colour space into another maintaining the differences between colours. Both in gamut and out of gamut colours can be changed. Used best when converting images with out of gamut colours from a large colour space to a smaller one.

 

Profile / Profiling

A file format developed by the ICC to contain information about the colour space of a device. Profiling is the act of making the profile

 

R

Relative Colorimetric

Rendering Intent where colours are mapped as accurately as possible, relative to the differences in white-point between the source and destination. In gamut colours are mapped very precisely and out of gamut colours are mapped to the closest in gamut colour. Good for converting colours where few are out of gamut of the destination.

 

RGB

Red, Green, Blue - red, green, and blue light are added together in various ways to reproduce a broad array of colours.

 

RIP

Raster Image Processor - software for converting data to a printable form for a printer, as opposed to using a printer driver.

 

S

Saturation

1) Purity of a colour

2) Rendering Intent that prioritises colour saturation over hue or lightness. Used with care this can produce a pleasing effect.

 

Soft-Proofing

Accurately previewing on a monitor how an image would print.

 

Source Profile

Profile used as the start point of a profile to profile conversion.

 

Spectrophotometer

A device for measuring the spectral characteristics of light.

 

sRGB

Microsoft and HP colour standard widely used. for the internet and consumer level cameras and printers.

 

Standard Illuminant

One of the CIE’s lists of standard light sources, for example D50, D65 etc.

 

Standard Observer

A definition created by the CIE for the typical human visual response.

 

T

Tagging

Embedding a profile in file.

 

Tonal Compression

Mapping a larger dynamic range onto a smaller one - something that happens in many profile to profile conversions.

 

U

UV

Ultraviolet - UV Brighteners are referred to in papers referring to Chemicals used to enhance the whiteness of paper that fluoresce under UV light.

 

UV Brighteners

Chemicals used to enhance the whiteness of paper that fluoresce under UV light.

 

W

White Point

The brightest white that can be reproduced by a device. For a print this is the paper white, for a monitor white point can be adjusted both in terms of colour temperature and luminance.

 

Working Space

A profile, sometimes an abstract one not created by measuring an particular device, used to store and edit data in, for example sRGB, Adobe RGB (1998) and Pro Photo RGB.

 

X

XYZ

CIE XYZ is a colour space that uses three primary colours, X,Y and Z as is a model for human colour perception. Used in colour calculations and as a profile connection space.

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