As an artist I see this all the time. One person says its green, another says its brown. Here is the question: Is it a physical difference in the eye that makes peope see different colors, or is it a mental descission that was made early in life where someone told them that was green and someone told you that was brown? Or was it nurture, where I am used to telling colors by the way oil paints and pencils show, others are used to them by other means and those means may define them differently than mine? Personally I am leaning towards the eye difference since I have been unable to convince people that green is green and not brown.