Application of a 3-CCD color camera for colorimetric and densitometric measurements

D. Brydges, F. Deppner, H. Kuenzli, K. Heuberger, R.D. Hersch

Electronic Imaging Conf. Color Imaging: Device Independent Color, Color Hardcopy and Graphic Arts III, SPIE Vol. 3300, 1998, pp. 292-301

Video cameras have been used in the graphic arts industry primarily for quality inspection applications where one is interested only in the macro or large scale appearance defects of the print i.e. acceptable/not acceptable. CCD video cameras also have the potential for use in on-press color-type measurements. The advantages of such measurements are numerous, most notably the ability to accurately determine what has been measured. However, despite the advantages current CCD cameras are not designed to measure colors directly. One of the major drawbacks to the use of standard 3-CCD cameras for such measurements is that the spectral response of the cameras differs from standard densitometric or colorimetric responses. Additionally, the dynamic range of the CCD camera is not suitable to accurately measure the densities attainable in high quality sheet-fed printing. This paper discusses techniques which have been used, and results obtained, in an attempt to acquire both densitome tric and colorimetric measurements from a standard 8-bit 3-CCD camera for use in newspaper printing.

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