Just to state the obvious, Tom’s switched back to a more natural coloring scheme as we’ve moved away from all of the moody evening lights and shadows.
I’ve tried to stretch out the transition between night and day over a couple of comics. ERB basically covers it in a sentence (check out the transcript). I’ve tried to bring it across above as, when Carter catapults out of the depths of the canyons, the sun’s already up in the sky, but he’s not been exposed to it as readily due to where he’s been. Hopefully that comes across okay.