The biggest problem with mars image coloration, especially by amataurs, is to match up the exposure times with reality. Its easy to make images look less red, especially using the images we're being given in the blue spectrum (L567) by straight matching, but unfortuntely that just isn't true color.

There is a program named Maestro (http://mars.telascience.org) which allows users to see calibrated (linearized) and balanced images in a 3D environment. Its a great program, and i definetly suggest that people check it out. There are, included with maestro, files describing the telemetry associated with a certain image, and investigating this reveals that the "auto-exposure time" ends up exposing the L2,L3 (red) images for a very short period of time (.7-.8 seconds) as opposed to the L6, L7 (blue) images which get exposed for 1.2-1.6 seconds. With twice the exposure time, its not unreasonable to figure why the images not taking this into account look "whiter" or more importantly, "bluer" than the JPL images. JPL is calibrating according to the exposure times, and not straight addition of images, which ends up brightening up the red.

I'll be the first in line to say that L2 L4 L5, or L2 L5 L7 are horrible RGB channels to use, mainly because of L2 being very far into the visible red part of the spectrum, but I'm not quite ready to accept that mars has a blue sky, or that its dust isn't very bright red.