Adobe photoshop cs2 사용자 설명서

ADOBE PHOTOSHOP CS2 

Converting to indexed color reduces the number of colors in the image to at most 256—the standard number of 
colors supported by the GIF and PNG-8 formats and many multimedia applications. This conversion reduces file size 
by deleting color information from the image. 

To convert to indexed color, you must start with an image that is 8 bits per channel and in either Grayscale or RGB 
mode. 

Choose Image > Mode > Indexed Color. 

For grayscale images, the conversion happens automatically. For RGB images, the Indexed Color dialog box appears. 

Select Preview in the Indexed Color dialog box to display a preview of the changes. 

Specify conversion options. 

When converting an RGB image to indexed color, you can specify a number of conversion options in the Indexed 
Color dialog box. 

A number of palette types are available for converting an image to indexed color. For the Perceptual, 

Selective, and Adaptive options, you can choose using a local palette based on the current image’s colors. It’s also 
possible to use a master palette that was created in ImageReady. These are the available palette types: 

Creates a palette using the exact colors appearing in the RGB image—an option available only if the image 

uses 256 or fewer colors. Because the image’s palette contains all colors in the image, there is no dithering. 

Uses the Mac OS default 8-bit palette, which is based on a uniform sampling of RGB colors. 

Uses the Windows system’s default 8-bit palette, which is based on a uniform sampling of RGB 

colors. 

Uses the 216-color palette that web browsers, regardless of platform, use to display images on a monitor 

limited to 256 colors. This palette is a subset of the Mac OS 8-bit palette. Use this option to avoid browser dither when 
viewing images on a monitor display limited to 256 colors. 

Creates a palette by uniformly sampling colors from the RGB color cube. For example, if Photoshop takes 

six evenly spaced color levels each of red, green, and blue, the combination produces a uniform palette of 216 colors 
(6 cubed = 6 x 6 x 6 = 216). The total number of colors displayed in an image corresponds to the nearest perfect cube 
(8, 27, 64, 125, or 216) that is less than the value in the Colors text box. 

Creates a custom  palette by giving priority to colors for  which the  human eye  has greater  sensi­

tivity.