Colour is the visual, perceptual property corresponding in humans to the categories called red, yellow, white, etc. and is derived from the spectrum of light interacting in the eye with the spectral sensitivities of the light receptors.
Color space fundamentals
Computer monitors emit colour as RGB (red, green, blue) light. Although all colours of the visible spectrum can be produced by merging red, green and blue light, monitors are capable of displaying only a limited gamut (range) of the visible spectrum.
Whereas monitors emit light, inked paper absorbs or reflects specific wavelengths. Cyan, magenta and yellow pigments serve as filters, subtracting varying degrees of red, green and blue from white light to produce a selective gamut of spectral colours. Like monitors, printing inks also produce a colour gamut that is only a subset of the visible spectrum, although the range is not the same for both. Consequently, the same art displayed on a computer monitor may not match to that printed in a publication.
CMYK colour separation
Colour originals must be “separated” so that the effect of full colour can be achieved by printing in only four colours. This is done by breaking down the original into three colours magenta, cyan and yellow, to which black is added to give finer detail and add density to dark areas.
It is possible to reproduce most colours from combinations of two or more of these four colours. For example, a purple is produced by mixing a percentage of magenta with a percentage of cyan, the proportions vary according to the particular shade required. However, certain colours are impossible to produce accurately using 4-colour process.
The Pantone colour formula guide provides an accurate method for the selection, specification, communication, reproduction, matching and control of solid Pantone Matching System colours, the international printing, publishing and packaging colour language.
Where special colours are required (ie not a four colour process), the Pantone system is used throughout the world as a convenient way of specifying a colour.
Pantone books contain tear-off swatches which can be attached to the artwork. However, the reference number alone is usually sufficient. Two colour jobs are usually black with a Pantone second colour.
The system is supported by a global Pantone colour communication network, comprised of companies licensed by Pantone to produce and distribute Pantone colour products and services. Printing inks in Pantone colours are available worldwide from licenced Pantone printing ink manufacturers.