control can be achieved on lithographic presses through the use of color
spectrophotometry. In this system, either the color bar portion of the image or the entire
image is scanned. The digital pixels are compared with a reference: either a measuring
proof, or some in-house standard. The press can then be adjusted to match the reference.
Required adjustments are accurately predicted and measured leading to less waste during
the makeready phase. Several presses can also be controlled by the correct color settings,
thus eliminating the need to produce waste during the adjustment of each press.
Source: Graphic Arts Monthly, February, 1999, p. 72.