A Method for Pre-Setting the Ink Distribution Keys for Offset Presses.

The study was for the purpose of reducing makeready time by quantitatively presetting ink distribution keys from data obtained using an estimating unit and a set of calibration curves. The photoelectric estimating unit was designed to read integrated densities of ordinary copy with the use of a series of lenses, a photoelectric tube and a meter movement. The unit yielded relative readings for image areas. The press was a standard offset type with calibrated ink fountain keys. A series of calibration tints were printed. For each tint, key settings and their estimated density values, curves were generated for use in the presetting of the ink keys. After sample copy was read using the estimating unit, a series of calculations were performed to find the ink key settings. All printed sheets were then evaluated to determine whether or not the presettings were producing copy within given specifications. The results of the study showed good correlation between pre-setting ink keys and copy printed within specifications.