Using The Palace Color Map
What the Heck's a CLUT?
Once you've opened the GIF, select "Color Table..." under the Photoshop "Mode" menu. A dialog will pop up, showing you the color table. Hit the "Save..." button. I saved mine as "Palace CLUT" ("CLUT" = "Color LookUp Table"). Once the CLUT is saved, you can just hit cancel on the dialogs and close the GIF you won't be needing the GIF any more.
The procedure is almost identical for GraphicConverter.
The chart below shows the Palace color map, rearranged in various strips. The top strip shows the map in the order it appears in the GIFs, and thus in Photoshop (The block of blacks at the end of the table is unused). Subsequent strips rearrange the color table, sorting on hue, on saturation, on brightness, on the red intensity, on the green, and finally on the blue.
Of special interest here should be the block of colors at hues of around 15 degrees or so (easily found in Photoshop by using the color picker directly below the letter "L" in the second row). Sadly, this region is not well-represented, and the colors in it are overly-saturated. Why is this region important? Because that part of the color wheel is where all the skintones (worldwide) live. That sometimes makes it very hard to nail a good flat-colored "skin" region on an avatar face especially for flat-colored cartoon characters. Why this color map was made the way it was, I can't answer.
Remember: Save Your RGB Image. You may need it later, for changes or fixes.
To convert an RGB image, you select "Indexed Color..." under "Mode." A dialog will pop up. In the "Palette" box, press the "Custom..." button. In the "Dither" box, press whatever you like "None" will generally give you the smallest file size, "Diffusion" the nicest tonal gradations. Now press "OK."
Another dialog will come up, showing you the color table. If it's still the Palace table (after a while, you'll get to recognize it!), just press "OK." If not, press "Load..." and load our "Palace CLUT" file. Now look at your image: it's living in the Palace world.
|RGB Original||No Dithering||Dithered|
Not sure about that "Dither" option? Just hit "Undo" and convert it again in several different ways. Or duplicate the image and convert each copy a different way, to compare side-by-side. Above are three samples, superimposed over a bit of Harry's Bar.
Here's how to do it with GraphicConverter.
Here's Even More on Color Tables.