Glossary
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.
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