You can open the "Gray balance calibration" dialog using the "Tools" menu in all the main functions.
In this dialog, you can set gray balance data for process calibration (see Calculate correction data).
General Information about Gray Balance
The gray balance is defined as a set of tonal values for cyan, magenta, and yellow that results in an achromatic color when printed and viewed according to specified conditions. Print conditions are defined in the applicable process standards (Process Standard Offset published by bvdm, German Association of Print and Media) based on ISO standards (ISO12647-2:2004/Amd1 2007).
Gray balance optimization does not contradict the ISO standard and the Process Standard Offset (PSO) but is a sensible complementary method. The correct perception of gray values is a key quality feature of a printed product. Gray values deviating from the printing material regarded as neutral color are rated disturbing.
There are special control strips for visual and metrological checking of the gray balance, such as ECI_GrayConS_FOGRA39.
As a rule, prepress uses standard profiles for defined print conditions. These standard profiles apply to defined tints and dot gains on a defined paper grades.
One example is the "ISOcoated_v2_eci" profile based on "FOGRA39L" characterization data for paper grades 1 and 2 (coated papers). This profile features a specific chromatic gray axis resulting from the overprinting of the Cyan, Magenta and Yellow process colors.
But deviations in gray rendition (paper white, inks, ink absorption, screening, etc) occur again and again in daily print shop practice. This means the gray balance in a print process is not a static but rather a dynamic factor depending on various parameters and therefore is prone to more or less readjustment as need be.
The rendition of gray will vary on different paper whites (e.g. due to optical brighteners) and with different inks in spite of correctly set tints and correctly calibrated dot gains.
Processes where defined dot gains are replaced with a defined gray balance cannot be correctly described by conventional process calibration methods and require new methods.