Abstract: The present invention proposes a method and a computing system for deducing ink thickness variations from spectral reflectance measurements performed on a printing press or on a printer. The computed ink thickness variations enable controlling the ink deposition and therefore the color accuracy, both in the case of high-speed printing presses and of network printers. Ink thickness variations are expressed as ink thickness variation factors incorporated into a spectral prediction model. The method for computing ink thickness variations comprises both calibration and ink thickness variation computation steps. The calibration steps comprise the calculation of ink transmittances from measured reflectances and the computation of possibly wavelength-dependent ink thicknesses of solid superposed inks. Wavelength-dependent ink thicknesses account for the scattering behavior of non-transparent inks or of inks partly entering into the paper bulk.

Abstract: The present invention proposes a method and a computing system for deducing ink thickness variations from spectral reflectance measurements performed on a printing press or on a printer. The computed ink thickness variations enable controlling the ink deposition and therefore the color accuracy, both in the case of high-speed printing presses and of network printers. Ink thickness variations are expressed as ink thickness variation factors incorporated into a spectral prediction model. The method for computing ink thickness variations comprises both calibration and ink thickness variation computation steps. The calibration steps comprise the calculation of ink transmittances from measured reflectances and the computation of possibly wavelength-dependent ink thicknesses of solid superposed inks. Wavelength-dependent ink thicknesses account for the scattering behavior of non-transparent inks or of inks partly entering into the paper bulk.