This investigation was aimed at establishing a relationship between the optical spread function of four common printing stocks (cast coat, enamel gloss, enamel dull and ledger) and a Yule - Neilsen n value in predicting physical dot Area, for offset lithographic printing. Using an offset press each paper stock was printed with a test target containing common screen frequencies at percent dot areas from 5-90"/. and solid ink patches adjacent to each tint. Using planimetry and macrodensitometry, exact n values were calculated for comparison with the measured spread function of that same paper stock. No relationship between the optical spread functions of the printing stocks and a Yule - Neilsen n value was found. Coated stocks (i.e., cast coat, enamel gloss and enamel dull) behaved differently than uncoated stock with respect to n values. This was found to be due to irregular ink coverage on the uncoated stock. n values were found to be screen frequency dependent.
Department, Program, or Center
Chester F. Carlson Center for Imaging Science (COS)
Lewis, Paul, "A study of the application of paper spread function data to the prediction of physical dot areas for offset lithography" (1986). Thesis. Rochester Institute of Technology. Accessed from
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