Calibration bars
From The Glossary of Digital Photography
Standardized bars printed on images or color separations to assist in confirming that the process is properly calibrated. These calibration bars are often a standard 11-step grayscale that prints from 0 percent to 100 percent in 10 percent increments. On color separations, a color calibration bar is printed. These calibration bars can be checked with a densitometer
for accuracy. See also calibration
