{HEAD ~ The modified alpha value} and the modified color of {TAIL ~ a pixel} are determined as a function of the amount of gray in the original color of the pixel 
of
{ HEAD ~ The modified alpha value } and the modified color of { TAIL ~ a pixel } are determined as a function of the amount of gray in the original color of the pixel
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH