Adobe 13101332 - Photoshop - Mac, User Manual, Page: 86 / 549

Using Help | Contents | Index Back 86
Adobe Photoshop Help Working with Color
Using Help | Contents | Index Back 86
Working with Color
About color modes and models (Photoshop)
A color mode determines the color model used to display and print images. Photoshop
bases its color modes on established models for describing and reproducing color.
Common models include HSB (hue, saturation, brightness); RGB (red, green, blue); CMYK
(cyan, magenta, yellow, black); and CIE L*a*b*. Photoshop also includes modes for
specialized color output such as Indexed Color and Duotone. ImageReady uses RGB mode
to work with images.
In addition to determining the number of colors that can be displayed in an image, color
modes affect the number of channels and the file size of an image.
You can set up the Info palette so that you can select any tool, position the pointer
over any part of an image, and determine the color value under the pointer. You can
customize the Info palette and color samplers to express color values using HSB, RGB,
CMYK, Lab, or Grayscale modes without changing the mode of the image itself. (See
“Seeing the color values of pixels (Photoshop)” on page 133 and the procedure to change
Info palette options in “Using the Info palette (Photoshop)” on page 32 .)
HSB model
Based on the human perception of color, the HSB model describes three fundamental
characteristics of color:
•
Hue is the 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 , sometimes called chroma , is the strength or purity of the color. 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 is the relative lightness or darkness of the color, usually measured as a
percentage from 0% (black) to 100% (white).