Your A–Z reference to colour management and related terminology
Aspect RatioThe Aspect Ratio of a monitor describes the proportions of its panel. The first figure relates to its width and the second to its height. However, many monitors can be rotated from landscape to portrait orientation. An aspect Ratio of 4:3 or 5:4 is classified a 'Standard Format' monitor, whereas 16:10 and 16:9 are classified as being 'Wide Format'.
Color ConfidenceEurope's largest independent colour management solutions provider and distributor. The colour division of TypeMaker Limited founded in 1986 by Geoffrey Clements and Simon Prais, Birmingham UK. Learn more about Color Confidence.
CalibrationA procedure that sets devices including cameras, monitors, printers and scanners with the aim of providing a basis for the accurate representation of colour.
In terms of print, 0% of a base colour will print 0 colour, 10% will reproduce 10% and so on up to 90% and 100%. In terms of a monitor or a camera, the RGB signals will be balanced to result in the white being the correct tone and brightness through to the shadows and the darkest point.
Calibration deals with the individual base colours, ideally through setting the hardware correctly, whereas profiling deals with how the base colours interact with each other.
CMYKCyan, Magenta, Yellow and black, the four base colours used by conventional print processes. Generally, images and graphics for print are required to be supplied in this format/mode.
A CMYK image comprises of four channels, one representing each of the four colour components. Similarly, a flat area of colour comprises percentages of the four components. Colour reference guides, such as the DCS publications provide an accurate colour printed reference to all CMYK colour combinations. Images in applications such as Photoshop can also be viewed and printed in the correct colours when using the correct CMYK Profile.
Due to the nature of CMYK print processes being highly dependent on the paper type, density of ink and other criteria, it is important to use a CMYK profile that corresponds to the particular print conditions. FOGRA 39 Coated is the current accepted print standard within Europe (this superseded FOGRA 27 which will also produce achievable colour).
Cdm2Candela per Square Meter – This unit of measurement is used to define the brightness intensity of emitted light, such as from a monitor. A comfortable level of brightness is 90-120 Cdm2. For soft-proofing purposes this should be set to an equivalent level to that of the light intensity of a viewing light reflecting off the paper print.
ColorimeterA colour measurement instrument. This type of instrument uses Red, Green and Blue filters to quantify and record each colour sample, similar to the process used by an image scanner. This is considered to be adequate for monitor calibration/profiling, whereas for measuring ink on paper and printer profiling a spectrophotometer is required. Learn more about Monitor Calibration and Profiling Solutions.
Colour TemperatureThe tone of white light, such as when referring to the white of a monitor’s display, digital camera image, or viewing light. A low temperature, such as that from household bulbs down to candlelight, has a yellow to orange tone (3,000-4,000°k), whereas daylight (5,000-6,500°k) crosses form a yellow-white to blue-white, and above this (7,000°k+) is a blue white.
Connection Types - MonitorsMonitors can offer a number of connection types or ports that accept a corresponding cable to communicate with a computer. Choice of connection port is determined by a combination of what ports options are available on the monitor and similarly on the computer (Graphics Card). Although many monitors offer a VGA connection, this is analogue and should only be used if the computer only has a VGA port. Preferably, a digital connection port such as DVI and DisplayPort should be used. HDMI is also a digital connection port type, generally used in AV (audio Visual) displays.
For a detailed explanation of Connection types, benefits and limitations, download the Cables and Connectors PDF from the learning Centre.
ContrastIn relation to a monitor, the difference between the darkest black and brightest white it can display (at maximum brightness).
In terms of a printed image, a high-contrast print exhibits exaggerated highlight and shadow areas, resulting in a loss of detail in the mid-tone range. Whereas a low-contrast image has a more uniform distribution resulting in a flatter looking image.
Contrast RatioThis term is used in the specification of monitors, and is calculated by dividing the maximum luminance achievable by the resultant black achievable. A monitor calibrated to a luminance of 100 Cdm2 with a minimum black of 0.25 will have a contrast ratio of 400:1 (100/0.25). A high contrast monitor is beneficial for watching DVDs (at a distance), but has no benefit for assessment of prints on screen, as the contrast of ink on paper is far lower than a minimum monitor specification.
CRTCathode Ray Tube (CRT) describes the technology used in old monitors (and televisions), prior to the use of flat LCD panels.
DaylightThe term used to describe optimum 'natural' light balance for viewing conditions. The colour balance of the sun's illumination ranges from 5,000k mid-morning to 6,500°k mid-afternoon. D50 is a pure illuminant close to 5,000°k and D65 close to 6,500°k. Print work is generally assessed in a Viewing Booth with D50 illumination and products/textiles under D65.
Learn more about Viewing Booth Solutions.
DCSDigital Color System - A range of visual colour reference products comprising of CMYK colour samples printed to ISO print specifications covering a comprehensive range of combinations on a range of media, presented in a logical easy to use format. Learn more about the DCS Range.
DensitometersA colour measurement instrument. This type of instrument uses Red, Green, Blue filters to quantify and record how dark a colour is. It does not measure the hue of the colour, just how dark it is – the Density. Its most common application is for calibration of a printing press where known base colours are being used and so the measurement objective it to check how think the ink is being applied to the paper (by how dark it is, with the assumption that its hue is correct). For measuring and correcting for the colour of ink on paper (and desktop printer colour management) a spectrophotometer is required.
DensityIn terms of print - how dark a colour is, as measured by a Densitometer.
Printing inks are transparent and the resultant colour is achieved from a combination of the colour pigments and the base paper colour. The thicker the layer of ink applied to paper, the darker the colour will appear. Similarly (and more crucial) the heavier the lighter tones will print, resulting in an incorrect colour balance.
DisplayPort (and mini DisplayPort) Connection DisplayPort - A digital connection port type for connecting a monitor to computer, it has the added benefit of including a USB feed within the cable configuration. This is newer technology than DVI, however DVI is still a popular and current format.
See Connection Types.
Dot Pitch (Pixel Pitch)The distance between each pixel on a monitor panel. A lower value/distance, results in a higher quality/resolution. A panel comprises of Red Green and Blue Sub Pixels, and this is based on the distance between pixels of the same colour. In practical terms, if a particular model of 22" monitor has the same resolution as a 24" monitor, but the 22" is physically 2" smaller than the 24" model, this is achieved through the smaller monitor having a smaller ‘Dot Pitch’. Both monitors will display the same area of an image, the image will simply be slightly smaller but look ‘sharper’ on the smaller monitor. The most common Dot Pitch distance for good desktop monitors is 0.27mm. Higher resolution monitors will be closer to 0.25 and lower resolution monitors increase to 0.28 and higher. Although a small dot pitch has the advantages of a sharper display and a physically space-saving size, a disadvantage to some can be the smaller display of menus and dialogues.
DVI ConnectionDVI-I, DVI-D and DVI-D Dual Link - Digital Connection port types for connecting a monitor to computer. See Connection Types.
FOGRA 39 CoatedThe resultant colour appearance achieved from printing CMYK inks on paper is dependent on numerous factors including; paper absorption, colour and ink density. In order to achieve consistent predictable colour the ISO have adopted the print standards defined by the ECI and FOGRA organizations. These print criteria are made available for preparing CMYK images for print or simulating press results on a proof printer in the form of the FOGRA 39 Coated ICC Profile, available within most graphics applications (Adobe color settings) and also directly from the ECI web-site. Set this profile when preparing images for CMYK print processes on coated paper stock.
In order to verify that a print complies with the ISO FOGRA specification, a Control Strip can be licensed for inclusion on proofs and final prints.
Proofing solutions such as the EFI RIP include the ability and license to print a FOGRA Control Strip within the software.
GamutThe term used to describe the extremities of the range of colours that can be achieved from a device (also dependent on the ink/media used in a printer or a monitor’s brightness level). i.e. the strongest reds, greens, blues, yellows, and darkest black. A ‘large gamut’ device will display or print stronger colours than a device with a smaller colour gamut.
HDMI ConnectionHDMI – A digital connection port type for connecting a monitor to computer. It includes the ability to carry audio data and it mainly benefits Audio-Visual displays. See Connection Types.
HoodA monitor hood is generally included in professional monitors and can be added to inferior monitors and laptops. A hood fixes to the bezel of a monitor (or around a laptop) providing a shield, top left and right to shade the monitor form external light sources that could disturb assessment of an image on the screen. In producing a ‘tunnel affect’ the monitor can subsequently also be set to a lower brightness level, requiring less power, extending the life of the monitor and reducing the chance of eye-strain, whilst providing a more realist representation of a printed image. Refer to ‘Light and Shade’ in the Learning Centre.
ICC ProfileAn ICC profile relevant to a particular device (camera/scanner/monitor/printer), describes how the device reproduces colour. When associated (assigned) to an image, an ICC profile defines the colour characteristics of each pixel colour combination within the image.
Learn more about solutions for profiling monitors, cameras and printers.
IPS PanelIn-Plane Switching (IPS), see Panel Types
LCDLiquid Crystal Display (LCD) is the standard type of panel used in monitors today. They are comparatively compact, lightweight and use less power than traditional CRT monitors. The majority of LCD panels are now based on LCD-TFT technology even if they are only labelled as being LCD (see TFT).
LuminanceThe intensity of brightness/illumination, as for a monitor. This is measured in Cdm2. A high level of monitor brightness, circa 160–450 Cdm2, extends the contrast of a display. This can be desirable for when viewing a movie but not advantageous for assessing/editing imagery against a reference print. See Cdm2 for further details of recommended luminance levels.
LUT / 3D-LUT / Dual 3D-LUTA monitor’s LUT (Look Up Table) controls the display of the digital information on to the monitor's panel. It holds information about the monitors calibration settings in order to achieve a smooth and uniform gradation from black to white through balancing the individual RGB output signals.
This balance and distribution determine the Temperature, Contrast and Luminance of the monitor. A 3D-LUT can achieve a higher level of accuracy. A Dual 3D-LUT has the ability to hold two independent calibration settings within the monitor, enabling the user to switch between two different sets of calibration criteria, through the monitors OSD.
MetamerismColours with different spectral wavelengths can visually appear identical under some viewing conditions.
For example, if the colour of a jacket and trousers match each other under shop lighting, but in day light they do not match each other, this is known as a ‘Metameric Pair’.
We experience colour when a light source is reflected/absorbed by a surface. A light source has its own characteristics, such as the differences of daylight to home or shop lighting. Subsequently, surface colour is influenced by the illumination type. However, some parts of the spectrum (and resultant colour) may be visible under one light source but not the other. If such a component is present in one surface and not another, the two surfaces can visually match each other under one lighting condition but look different to each other under other illumination.
The RHEM Strip is a specially printed indicator, available in packs of self-adhesive labels. It is printed in a metameric pair of colours, resulting in the label looking ‘plain’ in D50 illumination, but light/dark ‘stripes’ in other illuminations.
Native ResolutionThe number of Pixels across and down a monitor panel defines its Native Resolution. Setting a monitor at its Native Resolution results in the best and sharpest display. Setting a monitor (via the computer graphics card) to a lower resolution displays a larger image resulting in it being less sharp and displaying a smaller proportion of the image. If a particular graphics card or cable/connection type does not handle the full native resolution of a particular monitor, a lower resolution is used. Download the Cables and Connectors PDF from the Learning Centre for advice on this and graphics cards.
OSDThe OSD (On Screen Display) refers to the on-screen menu options to control your monitors settings. These menu options are normally accessed by selecting a button on the monitor that subsequently displays a list of menu options than can be navigated through to make your required options. The default positioning of the OSD is generally in the centre of the screen, however the menus choices will normally include the option for the display of the OSD to be positioned in a corner of the monitor.
A comprehensive range of professional and semi-professional standard monitors are described and rated in our Monitor Showroom.
Panel TypesLCD Monitor panel types vary in technology and quality. The three main types are, TN, PVA (MVA) and IPS (there are also variants within and between these types).
Twisted Nematic (TN): Commonly used in Laptops, this technology suffers from a limited colour gamut and severe shifts in colour and contrast through slight changes in viewing angle. So much so that such panels should not be relied on for colour critical work.
Patterned Vertical Alignment (PVA): These panels are superior to TN panels, and have the potential to display a wide colour gamut. However, when viewing from slight angles a shift in contrast (particularly in shadow areas) will be evident.
In-Plane Switching (IPS): Includes S-IPS, H-IPS and the newer P-IPS considered the best in panel quality technology, providing potential of a wide colour gamut and no obvious colour/contrast shift within the main viewing angle.
Physical SizeMonitors are generally classified in terms of the diagonal distance across the panel in terms of inches. However, its overall proportions will vary depending on its Aspect Ratio. A wide format 22" screen will be shorter in height than a 21" standard format monitor as the difference in width makes up its widescreen format additional width. Most new panels are now made to a wide screen format.
PixelThe individual dots, which form the image on an LCD monitor (see Native Resolution). Similarly, an image file comprises pixels of different colours to form an image. Each pixel can only be displayed in a single colour.
ProfilingThe name given to the procedure of measuring a series of colour samples in order to generate an ICC profile.
Learn more about solutions for profiling monitors, cameras and printers.
PVA PanelPatterned Vertical Alignment (PVA), see Panel Types
ResolutionSee Native Resolution.
Response TimeThis is the speed at which a screen updates the displayed image. This is mainly of relevance to editing movies and action gaming. Although a 'graphics' monitor may have a slightly slower 'response time' than a specialist movie editing system, this is not noticeable in general graphics use or when viewing a DVD.
RGBRed, Green and Blue are the three light sources that when mixed together produce a white light. Similarly, a scanner and a camera capture images in terms of their RGB component and a monitor/projector displays combinations of RGB light.
Size Specification - MonitorsThe size of a monitor can be defined by a number of aspects, its Physical Size, its Aspect Ratio, and also Pixels in terms of Native Resolution and Dot Pitch.
Standard Format - MonitorsThis describes the aspect ratio of a monitor. The 'traditional' standard format has a landscape aspect ratio of 4:3 proportion
SpectrophotometerA Spectrophotometer records the light reflectance values of a surface over a range of wavelengths. The series of measured values accurately defines the colour characteristics of the measured surface. See Spectrally Neutral.
A spectrophotometer, such as an i1-Pro instrument from X-Rite, is most commonly used for measuring colour from a desktop printer in order to make an ICC Profile. It can also be used to measure a set of known colour values (a control strip), to determine the level of colour accuracy against pre-recorded known colour values. Similarly, measurement can ascertain a closest colour match within a colour reference library – such as in a Pantone colour guide.
A Pressroom Instrument will be manufactured to a higher specification, will generally also be more robust and will store/display data without being tethered to a computer. They vary in functionality and it is generally found to be advantageous to have a model that can have its functionality expanded through remote software updates rather than being restricted to the abilities of a specific model.
Industrial instruments cater for the accurate measurement of surfaces other than ink on paper. This includes the weave of textiles and gloss of metals, plastics and other materials.
Spectrally NeutralIf the reflectance values measured at all wavelengths are equal, this indicates that the surface is a spectrally neutral grey. The lower the value, the closer to black, and a higher value closer to white. A red colour will record higher reflectance values through the red wavelengths. A coloured surface may appear to be 'neutral' under some lighting conditions, but if the surface is not perfectly neutral at all points along the wavelength, its appearance can produce unexpected results under some lighting conditions.
Take a look at our comprehensive range of Reference Charts.
Standard Format – MonitorsThis describes the aspect ratio of a monitor. The 'traditional' standard format has a landscape aspect ratio of 4:3 proportion.
TFTThin Film Transistor (TFT) is the type of LCD technology used in monitor panels, televisions and other displays up to 32" (diagonal). The letters TFT are commonly dropped when describing an LCD panel as it is accepted today that LCD monitor panels are of the TFT type. These panels, used in computer monitors, fall into one of the following categories: TN, PVA (MVA), and IPS (listed in order of lowest quality first). See Panel Types for further details and sub-categories.
TN PanelTwisted Nematic (TN), see Panel Types
UniformityMonitor Uniformity refers to the consistency (uniformity) of a display panel. A monitor with a poor level of uniformity may exhibit a pink or blue colour bias when viewing a neutral grey screen. Similarly, the panel could vary in luminance, resulting in an image appearing to have a higher contrast when viewed in one part of the screen to another. A monitor specified to have a high level of uniformity will be balanced in the factory to meet a specified level of uniformity across the panel.
Viewing Light/BoothAs different types of illumination and background colour affect the way we perceive colour, it is crucial to have a standarised viewing environment for visual colour assessment that is consistent and optimised to offer a clear and unbiased view. A viewing light/booth comprises of a source of illumination (tube/light bulb) of a specified temperature and high CRI (Colour Rendering Index - a method of describing the level of light purity). Its housing comprises of a neutral grey and the spread of light should be uniform within the assessment area.
For viewing prints a ‘Daylight’ D50 (5,000°k) lamp is normally used, or D65 (6,500°k) for textiles/products. Other illumination temperatures, specified for viewing products include TL84 and Cool White Florescent that relate to store lighting conditions.
For critical applications, viewing booths can also include the option of adding a UV (ultra violet) light component to the viewing conditions. In addition to showing changes in colour appearance caused by high UV levels, this also indicates the presence of artificial brighteners in a media or product (or even in inkjet paper) that subsequently fluoresce violet. The more recent generation of viewing booths are based on LED illumination and vary between those for daylight viewing and those with multiple controllable illumination types. A further consideration is viewing booths for ‘soft-proofing’ which require the inclusion of a dimmer switch so that the intensity of the illumination can be reduced from the ISO specification for comparing print against print, to the significantly lower intensity specified by ISO for comparing a print against a computer monitor. Take a look at our comprehensive range of Viewing Booths.
VGA ConnectionVideo Graphics Array - An analogue (RGB signal) connection port for connecting a monitor to computer. This is considered old technology and it is preferable to use higher quality digital connections. See Connection Types.
Wide Screen Format - MonitorsThis is the more popular of monitor formats, the additional space in the width being used to accommodate the growing number of palettes and toolboxes that can be displayed within applications. It is also, a more suitable format for movies. An aspect ratio of 16:10 is used in many wide-screen monitors, this results in the height of a 24" widescreen monitor being comparable to the height of a 21" standard format (4:3) monitor. Whereas some widescreen monitors are a wider format with a ratio of 16:9 similar to HDTV format. A 27" wide screen (16:9) monitor will have a similar height to that of a wide screen 24" (16:10) monitor, the main difference being additional width.
White Point/BalanceWhite Point is used in relation to monitors in describing its temperature setting. i.e. The ‘White Point’ of the monitor was set to 6,500k. The White Balance of a camera similarly refers to temperature and describes the lighting temperature of the shot.
This can be set/balanced through including a spectrally neutral Reference Chart in an image.