Adobe Illustrator CS4 User Manual

Page 103

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USING ADOBE ILLUSTRATOR CS4

Color

You can work with color values using the CMYK color mode, which is based on the CMYK color model. In CMYK
mode, each of the CMYK process inks can use a value ranging from 0 to 100%. The lightest colors are assigned small
percentages of process ink colors; darker colors have higher percentage values. For example, a bright red might contain
2% cyan, 93% magenta, 90% yellow, and 0% black. In CMYK objects, low ink percentages are closer to white, and high
ink percentages are closer to black.

Use CMYK when preparing a document to be printed using process inks.

See also

Change the color mode of a document

” on page 127

HSB

Based on the human perception of color, the HSB model describes three fundamental characteristics of color:

Hue

Color reflected from or transmitted through an object. It is measured as a location on the standard color wheel,

expressed as a degree between 0° and 360°. In common use, hue is identified by the name of the color, such as red,
orange, or green.

Saturation

Strength or purity of the color (sometimes called chroma). Saturation represents the amount of gray in

proportion to the hue, measured as a percentage from 0% (gray) to 100% (fully saturated). On the standard color
wheel, saturation increases from the center to the edge.

Brightness

Relative lightness or darkness of the color, usually measured as a percentage from 0% (black) to 100%

(white).

HSB color model

H. Hue S. Saturation B. Brightness

See also

Adjust the saturation of multiple colors

” on page 128

Lab

The CIE Lab color model is based on the human perception of color. It is one of several color models produced by the
Commission Internationale d’Eclairage (CIE), an organization dedicated to creating standards for all aspects of light.

The numeric values in Lab describe all the colors that a person with normal vision sees. Because Lab describes how a
color looks rather than how much of a particular colorant is needed for a device (such as a monitor, desktop printer,
or digital camera) to produce colors, Lab is considered to be a device-independent color model. Color management
systems use Lab as a color reference to predictably transform a color from one color space to another color space.

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