See Also: Why you need to reduce colors on raster images, Reduce colors manually

The number of colors that you select must include black and white even if there is no black or white on the image.

For example, if you were reducing the image above, you would need to reduce it to no less than four colors made up as follows: Blue, brown, white (compulsory), black (compulsory, even though there is no black on the image).

Scan2CAD automatically reduces the number of colors that are used on the raster image to the number of colors you select.

Based on the color distribution within the image it chooses which colors to retain and maps all the other colors to the most appropriate of the colors it has chosen, or to black or white.

Click to undo.

 You will sometimes get a better color reduction if you reduce the colors on an image to slightly more than you think you need. Then, do a manual color reduction to remove the extra colors.

You will sometimes get a better color reduction if you reduce the colors on an image in stages. For example, if you have a 16.7 million color image you might want to reduce it to 256 colors, then 64, then 4 rather than going from 16.7 million colors down to 4 in one step.

After you have reduced the colors on the image automatically, it is often a good idea to do a manual color reduction to remove any unwanted colors. These often occur as “fringes” at the edges of more dominant color blocks.

After you have reduced the colors on the image you may want to use Smooth and Remove Speckles to make the areas of color more uniform.

Problems? See Troubleshooting color reduction, Technical support