I agree with Flickerstreak.. Here is an off the wall idea but I have had luck in different pictures with it. Use a light source and remove light by going into the negative, also pick a color for the light that will give it an offset to the color problem you have. I can't help but think the problem I am seeing rests in the part of the picture I can't see.. I think it is coming from shadows of other objects and the sky.. I notice in the picture that the shin has a purplish cast to it, which seems to follow the hand pattern resting on his knee. This leads me to believe that shadows might be the problem. You might also check in the sky settings and see if a color is assigned to shadows. Byrce sky's no matter how tame can add some very nice or wierd effects to a picture. Thats all I can add at this point hope that helps.