Setting specific export options for GIF, Animated GIF, or PNG-Indexed format

Once you've decided on an export format as described in About export formats, and have chosen the high-level export options as described in Setting basic export options, you can specify document-level settings for GIF, Animated GIF, or PNG-Indexed format.

It's a good idea to use the Preview Export Compression command and watch the Composition window and the file size indicators to see how your choices affect the size and visual quality of your composition. (See Previewing compositions.)

To specify export options for GIF, animated GIF, or PNG-Indexed format:

1. Choose the general options for exporting as described in Setting basic export options.
2. Verify that you chose GIF, Animated GIF, or PNG-Indexed from the format pop-up menu at the top of the Export palette.
3. Specify the number of colors for the exported image by dragging the Colors slider or entering a value (2-256) in the text box. Shift-drag constrains the value to common color depths.
4. Select a color palette to set how colors are displayed in an operating system or a Web browser:
• Perceptual creates a custom palette by giving priority to colors for which the human eye has greater sensitivity. This palette usually produces images with the greatest color integrity.
• Selective creates a custom palette by sampling colors from the spectrum appearing most often in the image. For example, an 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.
• Web Adaptive creates a custom palette by shifting colors toward Web-safe colors, and preserves Web-safe colors on export.
• Web uses the standard 216-color palette common to the Windows and Mac OS Web-safe color palettes.
• Mac OS uses the default 8-bit color palette of the Mac OS, which is based on a uniform sampling of RGB colors.
• Windows uses the default 8-bit color palette of the Windows system, which is based on a uniform sampling of RGB colors.
5. Click the display options you want:
• Click the Include Transparency Information button to export the image with the object's alpha channel or active matte. (See Using alpha channels.)
• Click the Dither button  to mix the available colors to simulate unavailable colors. Dithering often improves the gradation after you have reduced the number of colors but increases the exported image's file size. You can see dithering with Preview Export Compression on.
• Click the Compress for Progressive Downloads button  to let browsers display a lower resolution image while the final image loads.
6. If you are exporting an animated GIF, choose a frame rate from the Frame Rate menu. Then choose how many times, if at all, you want the animation to loop or repeat.