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