Getting the Most from The Palace Color Map

Think Snappy!

The Palace color map is a full color wheel, but it's certainly limited in the choice of colors, compared to "full" 24-bit color images only 236 colors instead of 16 million+. Paint programs can do a super job converting for 24-bit to 8-bit, but you're better-off if you can nudge the process along a bit.

Muddy RGB Further, GIF and other images already have their own color maps what happens to them when we shift to the map used by The Palace?

Let's take a sample pic, with a character from the peerless Giant Robo series (and because no Palace site can have too many good-looking women with big guns...).

Even without masking (which would obliterate even more of the picture) we can see that there aren't a lot of distinct colors in here. Looks like someone was sloppy with the scanner... or maybe the original image was part of some larger picture, with its own contrast range.

Muddy GIF To check in Photoshop how things will all turn out...

Duplicate the image in another window
Resize to avatar or prop size (I picked 132 pixels)
Convert to index-color mode, using the Palace Palette
Convert to RGB mode
Select "Indexed Color..." again. There in the "Other:" box is the total color count. Only 33! And that's including the two or three dithered colors in our unmasked background. Ick!

So what to do?

First, crank up the contrast. I used the Photoshop "Image->Adjust->Levels..." dialogue, which gives you a great histogram for feedback. You could get similar (or even identical) results using the "Variations" dialogue or any ther sort of contrast-manipulating tool. I forced the hair values all the way down into the black, and the dress highlight all the way up to white. I also cranked the gamma so that more pixels would end up in the region below the middle gray. The on-screen image in my paint program immediately had loads more "snap."

Sharp GIF Next, I duplicate the image and do a 132-pixel resize, and follow it with a pass of "Unsharp Mask." Now, converting to Palace palette, we get more than twice as many colors: our convert/convert-back check shows 73 colors present in this version, a great improvement.

In this X's experience, beating on the original image's contrast and gamma ranges are the number one line of defense against muddy and incoherent palace prop images. The more colors you can get into the final prop, the clearer it will be.

Shifting from one color map to another can present its own suite of problems. Fortunately, many indexed-color images found on the web use the Netscape palette, which is very similar (identical?) to the one used by The Palace. When in doubt, call up the original image, duplicate it, convert to RGB, convert to the Palace CLUT, and view them together.

The most common problem here is dither noise (sometimes a problem with low-quality JPEGs, too). Functions like "despeckle" and "blur" can do a lot to solve it convert to RGB, run the filter, then convert to the Palace palette. In this illustration, expecially see the tones between the nose and nearer cheek.


An "alien" color-mapped image with 64 colors	Direct conversion to the Palace color palette	...Using Photoshop's RGB "Despeckle" filter

The undithering problem is really just a subtle variant of the halftone moiré problem so common in scanning from books and magazines. Despeckling and blurring will smooth-out the colors of the original image, creating new intermediate colors that can subsequently be more effectively re-dithered into the palace palette. You may also find that the problem is more-pronounced in one RGB color channel (say, green) than the others... so sometimes a careful bit of smudging by hand in just that one channel can be in order.