You Are Reading

Thursday 15 November 2012

Colour Theory - Hexachrome / Hue, Saturation & Brightness

Hexachrome is an ultra-high fidelity six-color process printing system developed by Pantone, Inc. It's large color gamut, compared to four-color process printing, makes it possible for the first time to more accurately reproduce a wide range of both vibrant and subtle colors that can be defined and displayed on computer monitors which previously could not be duplicated in print.

In Hexachrome, the existing CMYK primaries were modified into more chromatic inks, with orange and green being added to the traditional equation. In addition to reproducing more brilliant continuous-tone images, Hexachrome is capable of accurately reproducing over 90% of the PANTONE MATCHING SYSTEM® Colors, almost twice the number that can be obtained using conventional four-color process printing. This Designer Hexachrome Primer will show how to create a design using QuarkXPress™ that includes image separations using an Adobe® Photoshop® plug-in called PANTONE HexImage™, creating vector art in Adobe® Illustrator® with the PANTONE HexVector® plug-in, and creating a layout in QuarkXPress 4.0.4 with Hexachrome colors.

The prepress workflow for Hexachrome is similar to traditional CMYK, but color management systems need to be properly set up and plug-ins are required to enable support for Hexachrome in applications that do not have built in support. The printing workflow is the same as conventional process printing except there is six of everything instead of four.





Hue, saturation, and brightness are aspects of color in the red, green, and blue ( RGB ) scheme. These terms are most often used in reference to the color of each pixel in a cathode ray tube ( CRT ) display. All possible colors can be specified according to hue, saturation, and brightness (also called brilliance ), just as colors can be represented in terms of the R, G, and B components.

Most sources of visible light contain energy over a band of wavelengths. 

Hue is the wavelength within the visible-light spectrum at which the energy output from a source is greatest. This is shown as the peak of the curves in the accompanying graph of intensity versus wavelength. In this example, all three colors have the same hue, with a wavelength slightly longer than 500 nanometers, in the yellow-green portion of the spectrum.

Saturation is an expression for the relative bandwidth of the visible output from a light source. In the diagram, the saturation is represented by the steepness of the slopes of the curves. Here, the red curve represents a color having low saturation, the green curve represents a color having greater saturation, and the blue curve represents a color with fairly high saturation. As saturation increases, colors appear more "pure." As saturation decreases, colors appear more "washed-out."

Brightness is a relative expression of the intensity of the energy output of a visible light source. It can be expressed as a total energy value (different for each of the curves in the diagram), or as the amplitude at the wavelength where the intensity is greatest (identical for all three curves). In the RGB color model, the amplitudes of red, green, and blue for a particular color can each range from 0 to 100 percent of full brilliance. These levels are represented by the range of decimal numbers from 0 to 255, or hexadecimal numbers from 00 to FF.


No comments:

Post a Comment

About Me

My photo
Leeds College of Art. Graphic Design.
 

Copyright 2010. All rights reserved.