One method for producing the halftone screen is now explained in formal terms for {HEAD ~ the gradation correction} using {TAIL ~ a non periodic screen function} 
using
One method for producing the halftone screen is now explained in formal terms for { HEAD ~ the gradation correction } using { TAIL ~ a non periodic screen function }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL