This will reduce the number of colors in the image to a maximum of 256 distinct colors.
· Adaptive This will select the 256 best colors for the image. The palette generated for the image is optimized and unique for this image.
· System This will use the 256 fixed colors in the system palette. The palette for the image is fixed. Images converted to system palette will all have the same palette.
· 8-8-4 levels This will use the vaunted 3-3-2 bits fixed palette, that is, a palette with 8 intensity levels for the Red and Green components and 4 levels for Blue. This palette was used in the 2.x versions of Microsoft Windows.
· 6-7-6 levels This will use a 6-7-6 level fixed palette, that is, a palette with 6 intensity levels for the Red and Blue component and 7 levels for Green, thus the image will be reduced to a maximum of 252 colors.
· 6-6-6 levels This will use a 6-6-6 level fixed palette, that is, a palette with 6 intensity levels for each color component (Red, Green, Blue), thus the image will be reduced to a maximum of 216 colors. This palette is well suited for systems with palette manager since the Palette Manager works best if the palette contains no more than 236 color entries.
· None The colors will be selected on best match basis. The color error is not compensated.
· Ordered Ordered dithering is used to compensate the error. Ordered dithering can only be used with R-G-B level palettes.
· Diffusion Floyd-Steinberg error diffusion dithering is used to compensate the color error.
Number of colors
If you have selected Adaptive Palette this will let you select the maximum number of distinct colors in the image.