A1call thanx for PM.

Given more 'review' I found this link:
http://www.highmars.org/niac/education/mer/mer00b.html

and finding more on this page I had forgotten about:

http://www.highmars.org/niac/education/mer/mer00.html

I am willing to say that under 'normal' conditions 'true color' would be :
RL4-GL5-BL6
as these are in the MIDDLE of the color spectrum for human eyes.

In using both L2 and L7 it seems to me BOTH extremes would be used and thus 'canceled' out. But I am willing to concede this may NOT be the case.

So Let's say it's a given that the 'natural' true color is RL4-GL5-BL6 to correctly reproduce the calibration target on Earth at high noon.

How does one 'change' the L2 and L7 filter images to more approximate L4 and L6 respectively at high noon on Mars?

Bob...