-- card: 72580 from stack: in -- bmap block id: 0 -- flags: 0000 -- background id: 2287 -- name: -- part contents for background part 1 ----- text ----- MacWorld-pg 116 -- part contents for background part 11 ----- text ----- 10/88 -- part contents for background part 12 ----- text ----- A Halftone Handbook Halftones Image scanners Screen ruling (frequency) Angle dithering TIFF; RIFF; ten-ninety halftone (10/90) xref MacUser-pg 257 (2/89) excellent tutorial on half tone mechanics and gray scales.