how do I modify colormaps in .eps?

[fournier]

I have some .eps files created by matlab, of which I would
like to change the colormaps. That is, I am happy with
everything in the images, plots etc. except the colormaps. I
can't recreate the files because the raw data is gone, and it
would be laborious to load each file into xv, although that
would work. I can probably write a script that uses sed, but I
hope someone can tell me a slick way to do this with gs or
something. Please cc address@hidden