Glossary, page 1
A
Additive Primaries
Red, green, and blue light. When all three additive primaries are combined at 100% intensity, white light is produced. When these three are combined at varying intensities, a gamut of different colours is produced. Combining two primaries at 100% produces a subtractive primary, either cyan, magenta, or yellow:
100% red + 100% green = yellow;
100% red + 100% blue = magenta;
100% green + 100% blue = cyan
See Subtractive Primaries.
100% red + 100% green = yellow;
100% red + 100% blue = magenta;
100% green + 100% blue = cyan
See Subtractive Primaries.
Appearance
Manifestation of the nature of objects and materials through visual attributes such as size, shape, colour, texture, glossiness, transparency,
opacity, etc.
opacity, etc.
Attribute
Distinguishing characteristic of a sensation, perception or mode of appearance. Colours are often described by their attributes of hue, saturation or chroma, and lightness.
B
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 colorants are combined, the resulting colour; theoretically; is black. In real world applications, this combination produces a muddy gray or brown. In four-colour process printing, black is one of the process inks.
The letter "K" is used to represent Black in the CMYK acronym to avoid confusion with Blue's "B" in RGB.
When 100% cyan, magenta, and yellow colorants are combined, the resulting colour; theoretically; is black. In real world applications, this combination produces a muddy gray or brown. In four-colour process printing, black is one of the process inks.
The letter "K" is used to represent Black in the CMYK acronym to avoid confusion with Blue's "B" in RGB.
Brightness
The attribute of visual perception in accordance with which an area appears to emit or reflect more or less light (this attribute of colour is used in the colour model HSB—Hue, Saturation, Brightness). See Lightness.
C
Calibration
To check, adjust, or systematically standardize the graduations of a device.
Chroma
The attribute of visual perception in accordance with which an area appears saturated with a particular colour or hue, for example; a red apple is high in chroma; pastel colours are low in chroma; black, white, and gray have no chroma (this attribute of colour is used in the colour model L*C*H - Lightness, Chroma, Hue).
Also referred to as Saturation.
Also referred to as Saturation.
Computer-to-Plate (CTP)
A technology that allows for the delivery of digital data directly to a plate for printing. CTP efficiency eliminates conventional films and stripping to significantly reduce prepress materials and costs, and allow for significant productivity and quality benefits over other commercial printing solutions.
CIE (Commission Internationale de l'Eclairage)
A French name that translates to International Commission on Illumination, the main international organization concerned with colour and colour measurement.
CIELAB (or CIE L*a*b*, CIE Lab)
Colour space in which values L*, a*, and b* are plotted at right angles to one another to form a three-dimensional coordinate system. Equal distances in the space approximately represent equal colour differences. Value L* represents Lightness; value a* represents the Redness / Greenness axis; and value b* represents the yellowness/blueness axis. CIELAB is a popular colour space for use in measuring reflective and
transmissive objects.
transmissive objects.
CIE Standard Illuminants
Known spectral data established by the CIE for four different types of light sources. When using tristimulus data to describe a colour, the illuminant must also be defined. These standard illuminants are used in place of actual measurements of the light source.
CIE Standard Observer
A hypothetical observer having the tristimulus colour mixture data recommended in 1931
by the CIE for a 2° viewing angle.
A supplementary observer for a larger angle of 10° was adopted in 1964. If not specified, the 2° Standard Observer should be assumed. If the field of view is larger than 4°, the 10° Standard Observer should be used.
by the CIE for a 2° viewing angle.
A supplementary observer for a larger angle of 10° was adopted in 1964. If not specified, the 2° Standard Observer should be assumed. If the field of view is larger than 4°, the 10° Standard Observer should be used.
