Process for recording semihalftone images

Abstract From the Canadian patent

A process involving scanning an original linewise and determining the tonal value of each scan dot. Multiple scan dots are collected into a scan field. The average tonal value of each scan field is determined by averaging the tonal values of the scan dots of that scan field. The original is reproduced on a recording medium by individual recording dots that can take the tone value "print" or "no-print". Several recording dots correspond to a scan field of the original. The tone value of the scan field can be reproduced almost exactly on the average by printing a specific number of recording dots. The distribution of recording dots to be printed for a scan field is determined by subdivision …