Adobe 29180155 User Guide - Page 153

ADOBE PHOTOSHOP ELEMENTS 4.0 148 User Guide • System (Windows) Uses the Windows system's default 8-bit palette, which is based on a uniform sampling of RGB colors. • Web Uses the 216 colors that web browsers, regardless of platform, use to display images on a monitor limited to 256 colors. Use this option to avoid browser dither when images are viewed on a monitor display limited to 256 colors. • Uniform Creates a palette by uniformly sampling colors from the RGB color cube. For example, if Photoshop Elements takes 6 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. • Local or Master Perceptual Creates a custom palette by giving priority to colors to which the human eye has greater sensitivity. Local Perceptual applies the palette to individual images; Master Perceptual applies the selected palette to multiple images (for example, for multimedia production). • Local or Master Selective Creates a color table similar to the Perceptual color table, but favoring broad areas of color and the preservation of web colors. This option usually produces images with the greatest color integrity. Perceptual applies the palette to individual images; Master Perceptual applies the selected palette to multiple images (for example, for multimedia production). • Local or Master Adaptive Creates a palette by sampling the colors from the spectrum appearing most often in the image. For example, an RGB image with only the colors green and blue produces a palette made primarily of greens and blues. Most images concentrate colors in particular areas of the spectrum. To control a palette more precisely, first select a part of the image that contains the colors you want to emphasize. Photoshop Elements weights the conversion toward these colors. Perceptual applies the palette to individual images; Master Perceptual applies the selected palette to multiple images (for example, for multimedia production). • Custom Creates a custom palette by using the Color Table dialog box. Either edit the color table and save it for later use, or click Load to load a previously created color table. This option also displays the current adaptive palette, which is useful for previewing the colors most often used in the image. • Previous Uses the custom palette from the previous conversion, making it easy to convert several images with the same custom palette. Color Specifies the number of colors to include in the color table (up to 256) for Uniform, Perceptual, Selective, or Adaptive palettes. Forced Provides options to force the inclusion of certain colors in the color table. Black and White adds a pure black and a pure white to the color table; Primaries adds red, green, blue, cyan, magenta, yellow, black, and white; Web adds the 216 web-safe colors; and Custom lets you define custom colors to add. Transparency Specifies whether to preserve transparent areas of the image during conversion. Selecting this option adds a special index entry in the color table for a transparent color. Deselecting this option fills transparent areas with the matte color, or with white if no matte color is chosen. Matte Specifies the background color used to fill anti-aliased edges that lie adjacent to transparent areas of the image. With Transparency selected, the matte is applied to edge areas to help blend the edges with a web background of the same color. With Transparency deselected, the matte is applied to transparent areas. Choosing None for the matte creates hard-edged transparency, if Transparency is selected; otherwise, all transparent areas are filled with 100% white.