Determining the color repeatability of images from color output devices is paramount for color-critical
applications. Color should be described in coloriinetric values which are then used to make a probability statement
about printed color repeatability.
Experiments are described that determine color repeatability for a four color continuous ink jet printer
using colorimetric methods and probability ellipses. CIELab measurements were taken from several ink jet prints
which contained a standard test image. The test image consisted of an array of color patches with different colorant
amounts. Two-dimensional ellipses, representing the 95% a*,b* confidence interval, were then computed for each
color patch to establish color repeatability. Typical results showed that ellipse axes were not parallel to the a*,b*
axes, suggesting that simple a*,b* tolerances would lead to an inaccurate repeatability statement.