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