The Rainbow Valley was the first stop on our 4WD trip : i.e. first time unfolding the tents, first canned food dinner, first night alone in the middle of nowhere. And for a first camping spot, it was simply terrific! Perfect light, awesome scenery, and not a single fly! (which unfortunately was going to be pretty different further south)
We were lucky since the claypan in front of the cliff was partially filled with water (it rained for three days while we stayed in Alice Springs). The color variations are due to rock composition (iron-oxide darkens the top while it was washed away from the lower portions).