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Color Calibration with a Densitometer

IP.com Disclosure Number: IPCOM000118945D
Original Publication Date: 1997-Sep-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

Decker, WC: AUTHOR [+3]

Abstract

In order to minimize color errors in a full process color printer, the optical density of each color must be kept constant for all levels of tonal quantity (grey level). In order to accomplish this, optical density readings of each color at various grey levels are taken using a densitometer. Printer parameters are then adjusted such that all the optical densities are kept at constant calibrated values.

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Color Calibration with a Densitometer

      In order to minimize color errors in a full process color
printer, the optical density of each color must be kept constant for
all levels of tonal quantity (grey level).  In order to accomplish
this, optical density readings of each color at various grey levels
are taken  using a densitometer.  Printer parameters are then
adjusted such that all the optical densities are kept at constant
calibrated values.

      A significant error can be introduced if the densitometer used
is not calibrated or if its characteristics are different from the
densitometer originally used to obtain all the calibrated values of
the optical density.  The latter may occur frequently as one print
shop will use densitometers that are different from another and
different from the one upon which the calibrated density values were
obtained.

      A solution to this problem of using different densitometers is
to print standard patches at the time that the original density
calibration took place.  These standard patches are of all the colors
and at the different density levels associated with calibration.
These sheets of calibrated patches are shipped with the printer.  The
calibration procedure for the printer while the field is quite
simple.  The optical densities of all of the color patches from the
calibrated sheets are obtained with whatever appropriate densitometer
is available.  Then, the equivalent patches are printed by the
printer...