Color Bars

Color bars are carried on all four-color process jobs to show the amount of ink used, the trapping, and the relative densities across the press sheets. The main cause of color variations in multicolor offset printing is uncontrolled dot gain. Good offset printing depends on controlled and stable dot gain. A color bar is a guide for the platemaker, pressman and customer.

A color bar monitors most of the issues …

Add this to Solid Density Patch - The solid density patch is used to monitor the solid density. The values listed below are characteristic for prints on coated paper, when they are measure with reasonable new and well maintained densitometers.

Yellow .90 to 1.00
Cyan 1.25 to 1.30
Magenta 1.30 to 1.35
Black (halftones) 1.60 to 1.70
Solid black 1.70 to 1.80

(These values could slightly vary with different systems)

The values apply when the densitometer is zeroed on paper whites. On matte coated papers the recommended values are on the average lower by 0.10 than indicated above.

Add this to Gray Balance Patch
Gray Balance Patch - Dot values of 50% cyan, 41% magenta and 41% yellow were selected to produce a neutral midtone grey.