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Colour Brightness & White Brightness for Projectors

Download Buyer´s Guide to Colour Brightness (PDF)


720p – A 16:9 aspect ratio of 1280 x 720 pixels in progressive non-interlace mode. Total pixels of 921,600

1080p – A 16:9 aspect ratio of 1920 x 1080 pixels in progressive non-interlace mode. Total pixels of 2,073,000

3LCD – Abbreviation for 3 Chip Liquid Crystal Display

Additive Primaries – Red, green and blue light. When all three additive primaries are combined at 100% intensity, white light is produced.

Additive RGB colour space – A colourimetric colour space having three colour primaries (generally red, green and blue) such that CIE XYZ tristimulus values can be determined from the RGB colour space values by forming a weighted combination of the CIE XYZ tristimulus values for the individual colour primaries.

Black – The absence of all reflected light; the colour that is produced when an object absorbs all wavelengths from the light source. When 100% cyan, magenta, and yellow colourants are combined, the resulting colour, theoretically, is black. In real-world applications, this combination produces a muddy grey or brown.

Blue – One of three additive primaries

Chromaticity coordinates – Coordinates that specify position in a chromaticity diagram. The chromaticity coordinates of a stimulus are derived from its tristimulus values by taking the ratio of each of the tristimulus values to their sum.

Chromaticity diagram – A diagram that represents the unit plane (the plane defined by the equation X+Y+Z=1) in a tristimulus space. The location of a stimulus with a particular set of tristimulus values on a chromaticity diagram represents its direction from the origin of the space ignoring its distance.

CIE – Commission Internationale de l'Eclairage. An international organisation that recommends standards and procedures for light and lighting.

Colourimeter – Instrument for measuring colourimetric quantities, such as the tristimulus values of a colour stimulus.

Colour Brightness – Measurement of colour output from a projector. The higher the Colour Brightness the more vivid and realistic the colour. Also known as Colour Light Output.

Colour Filter Wheel – Mechanical device consisting of 3 or more colour filters used in 1-chip projection systems.

Dichroic mirror – Optical device used in a 3-path projection system to divide light into multiple beams. Each dichroic mirror is tuned to reflect specific wavelengths of light while allowing other wavelengths to pass through. For example, a dichroic miror may reflect red light but allow blue and green light to pass through.

Colour Gamut – The range of different colours that can be interpreted by a colour model or generated by a specific device.

Colour Light Output – IDMS 15.4 standard for the measurement of colour output from a projector. Also known as Colour Brightness.

Colour Space – An geometric representation of colours in space, usually of three dimensions describing the way colours can be represented as tuples of numbers, typically as three or four values or colour components (e.g. RGB and CMYK are colour models) with sRGB, Adobe RGB 1998 and Pro Photo RGB as colour spaces.

Colour Wheel – Colour theory tool used by creative professionals

Complementary colours – Two colour stimuli that can be additively mixed to produce an achromatic colour.

Contrast – The level of variation between light and dark areas in an image.

Cones – Photoreceptor cells in the retina of the eye responsible for colour vision.

Cyan – One of the process ink colours for printing.

CMY – Subtractive colours of Cyan, Magenta and Yellow.

CMYK – A colour model used in 4-colour offset printing.

DLP – Abbreviation for Digital Light Processing.

Gamut Mapping – Converting the coordinates of two or more colour spaces into a common colour space.

Green – One of three additive primaries

ICDM – Abbreviation for International Committee for Display Metrology

IDMS – Abbreviation for Information Display Measurements Standard. Also known as the International Display Measurement Standard. For download visit: http://icdm-sid.org/

IDMS 15.4 – Standard for Colour Light Output

Hue – The basic colour of an object, such as 'red', 'green', etc. Defined by its angular position in a cylindrical colour space, or on a Colour Wheel.

ICC – International Colour Consortium, industry body responsible for the ICC profile specification and colour management architecture.

Ishihara – A test for colour blindness

K – Black Ink used in mass production photomechanical printing processes, used to represent black in the CMYK acronym to avoid confusion with blue's 'B' in RGB.

Kelvin (K) – Unit of measurement for colour temperature.

Lumen – A measure of the total 'amount' of visible light emitted by a source.

Lux – One lumen per square metre.

Magenta – One of the process ink colours for printing.

Munsell Colour System – Widely used system for describing the colour appearance of samples. The Munsell system uses matching against a set of samples and interpolation between them to arrive at a designator for the appearance of a given test sample.

Pixel – A small 'picture element' that contains red, green and blue information for colour rendering.

RGB – Additive primaries of Red, Green and Blue, also describes a colour model.

Red – One of 3 additive primaries.

Resolution: – Measurement of how finely an image is resolved by the number of pixels.

sRGB – Colour space originally designed for the web.

Subtractive Primaries – Cyan, Magenta, and Yellow. When all three subtractive primaries are combined at 100% on white paper, black is produced.

Saturation, Chroma, Colourfulness – Saturation Colourfulness and Chroma are related but distinct concepts referring to the perceived intensity of a specific colour. Colourfulness is the degree of difference between a colour and grey. Chroma is the colourfulness relative to the brightness of another colour that appears white under similar viewing conditions. Saturation is the colourfulness of a colour relative to its own brightness.

SID – Acronym for The Society of Information Display http://www.sid.org/

Spectrophotometer – Instrument measuring the intensity or transmitted light as a function of wavelength or colour.

Spectroradiometer – Instrument measuring the spectral power distributions of illuminants.

SVGA – Super Video Graphics Array, the number of pixels a projector is capable of displaying in a standard 4:3 aspect ratio of 800 Horizontal, 600 Vertical totalling 480,000 pixels.

SXGA & SXGA+ – Super XGA, standard screen resolution of 1280x1024 pixels. SXGA was common on standard monitors, but provided a 1.25:1 aspect ratio, compared to the more common 1.33:1 (4:3) ratio. SXGA+ was a 1400x1050 resolution, which is an exact 1.33:1 ratio with total pixels of 1,470,000

Tri-stimulus Colourimetric – A set of techniques for predicting colour matches by equating a given stimulus with the amounts of three specified primaries that would be required to match it. The amounts of three primaries that would be required to match the stimulus are the tristimulus values of that stimulus for that set of primaries.

Tristimulus Values – Amounts of three primary lights that, when mixed additively, will match a given light to a given observer.

UXGA – Ultra Extended Graphics Array is 1600 pixels horizontally by 1200 pixels vertically (1600x1200). This amounts to a total of 1,920,000 pixels on the screen in a 4:3 aspect ratio.

WUXGA – Wide Ultra XGA, a wide screen resolution of 1920x1200 or 1920x1080 pixels in a 16:10 aspect ratio

WXGA – Wide XGA, a wide screen resolution of 1280x800 in a 16:10 aspect ratio with a total number of pixels of 1,024,000.

XGA – Extended Graphics Resolution, the number of pixels a projector is capable of displaying in a standard 4:3 as aspect ratio of 1024 Horizontal, 768 Vertical totalling 786,000 pixels.

Yellow – One of the process ink colours for printing.

White Brightness – Measurement of White Light Output of a projector without regard to colour.

Download Buyers Guide to Colour Brightness(PDF)
Download the International IDMS 15.4 Standard