From:
http://www.fredmiranda.com/forum/topic/1070288rico
Having become aware of impure color sources, I can't see anything else. Kind of ruined my enjoyment of outdoor photography unless there's heavy overcast, and owning a color meter just feeds the obsession. Note the green cast on the underside of that golf ball. Now, please excuse me, I must return to my light tent!I can't imagine photographers spending $1000 on a color meter and not having the slightest understanding of the behavior of light. I used to answer topics like this until Fred Miranda decided I was somehow the enemy.
I sincerely hope my forum readers have more knowledge than shown here and regularly on FM and other forums. If not, I'm alway happy to provide intelligent answers.
The answer to this dilemma is:
Rico, The golf ball is lit on the top by direct sunlight at about 5500°K, while the bottom is lit by light bounced off the green grass . . . of course the bottom side has a green cast . . . it ain't rocket science, it's lighting 101.