Minimizing browser dither

To protect colors from dithering in a browser, you can shift the colors to their closest equivalents in the Web palette. This ensures that the colors won't dither when displayed in browsers on either Windows or Macintosh operating systems capable of displaying at least 256 colors.

To shift a single color to its closest Web palette equivalent:

1 With an optimized image displayed, use the eyedropper tool () in the Save For Web dialog box to select a single color. Alternatively, click a color in the Color Table panel.

2 In the Color Table panel, click the Web Shift button () to shift the color.

A small white diamond appears in the center of a Web-shifted color and in all Web-safe colors.

To shift a group of selected colors to the closest Web palette equivalents:

1 With an optimized image displayed, select colors in the Color Table panel, as described in Selecting colors.

2 Click the Web Shift button or choose Web Shift/Unshift Selected Colors from the Color Table panel menu.

A small white diamond appears in the center of selected colors that have been Web-shifted (and in all Web-safe colors). If the selection includes both shifted and unshifted colors, all colors in the selection become shifted colors.

To revert Web-shifted colors to their original colors:

Do one of the following:

To specify tolerance for shifting colors automatically to the closest Web palette equivalents:

In the Optimize panel of the Save For Web dialog box, enter a value for Web Snap or drag the pop-up slider. A higher value shifts more colors.

Images and Page Design > Previewing and controlling dithering in Photoshop images > Minimizing browser dither