In one embodiment, {HEAD ~ coatings} of initially colorless color formers and color developers are coated on {TAIL ~ selected areas} of a substrate surface 
In one embodiment , { HEAD ~ coatings } of initially colorless color formers and color developers are coated on { TAIL ~ selected areas } of a substrate surface
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH