Posterization and colorshifting occur when the sRGB version is subjected to a Levels midtone increase from 1.00 to 2.00 and Saturation increase of +50. The spikes on the shadowed end of the histogram indicate how the darkest greens and blues remain pinned there, causing the darkest greens to become posterized, and the darker reds to turn purple, instead of each merely becoming brighter and more saturated.