Thanks for the suggestions. I tried colorize and began to think that if I could just remove the darkest and lightest colors I could get a good result. So I experimented with Color to Alpha. I would make a plasma layer, then use colorize to make it a single hue - a blue for example, then use Color to Alpha to take out the black, then use Color to Alpha again to take out the white, then make a new layer and repeat the process with another hue - red for example.
http://www.cartographersguild.com/at...0&d=1299003661
It seemed to work very well until I wanted to get a darker color in. That technique doesn't allow dark colors, and black is too dark to not filter out. Since the Color to Alpha doesn't seem to have a threshold control or whatever its called, there doesn't seem to be much adjustment for that. I tried union select and delete, but that seems to either blur the image too much if feather is used or remove too much of the... inner color detail?

Anyway, using the channel mixer:
http://www.cartographersguild.com/at...1&d=1299003685
Everything seems to look great. I had never used the channel mixer before, but this I think is definitely my favorite way to do this.