Color Blind

As I ponder whether to register and actually pay for art courses I'm sampling free demos at the local art supply store this month. Two days ago I attended one by a recently retired tax accountant who has been an established painter since the 70's.  Not only did I appreciate hearing that many of his accounting clients had been artists but was also intrigued when this painter said he was red green color blind.  Apparently this has made him mix unusual greens which many buyers said made his art more interesting.  Even if his wife has to tell him occasionally that his colors have gone very off, he says for him painting is mainly about form and color values, ie. light, medium, and dark. In his opinion the specific colors themselves are almost irrelevant and completely interchangeable.  Wow!  Revolutionary thought for me who is so color sensitive. Have to ponder this for a while.