The message at the end of the very cool new NASA JPL video Curiosity at Martian Scenic Overlook says
To aid geologists, colors in the image are white balanced so rocks appear the same color as the same rocks would on Earth.
Mars and Earth share the same Sun, and the color of sunlight doesn't shift with distance, so the change is perhaps related to different atmospheres?
How much of a shift was needed for the white balancing of these Curiosity images? Is it just a few percent variation, or much larger?
Bonus: What are the factors used to determine how to perform this white balancing? Is it done using a built-in color palate specimen on Curiosity, or from known parameters of Mars' atmosphere?