Determination of Chromaticness Difference Tolerance of Offset Printing by Means of Simulation

Printing quality can be defined as conformance to specifications. ISO 12647-2 (2004), the standard for offset lithographic printing, specifies solid, TVI and mid-tone spread as conformance metrics. The revision of ISO 12647-2 (2010) embraces ΔCh as a new metric for grey reproduction assessment. In order to complete the revision, both the test method and the tolerance must be specified. In his presentation at TC130 in April 2011, Chung proposed a three triplets\u27 method as input to the grey reproduction assessment. He also proposed the use of G7 pass/fail criteria as the criteria to determine the tolerance in terms of ΔCh. This research extends Chung\u27s work by using TVI and midtone spread tolerances as the criteria to determine the grey reproduction tolerance in terms of ΔCh. Because these tolerances are based on TVI and midtone spread, they should be better in line with the foundation of ISO 12647. Two hundred fifty six simulations of TVI drift from four different calibrated press conditions were used to develop proposed ΔCh tolerances. Berns\u27 methodology was used to minimize disagreement between ΔCh tolerances and the existing midtone spread tolerance of 5. The resulting ΔCh tolerances exhibited nearly 90% agreement for quarter-tone and midtone near neutral patches, and nearly 80% agreement for the three quarter tone neutral patch