â–³Ch (Delta Ch)
Close to the gray axis, in other words for near neutral colors, the usage of Delta H is not
appropriate enough. Instead, the usage of the â–³Ch (Delta Ch) metric is proposed.
The metric that is called chromaticness can reveal gray balance errors.
The weighted ΔCh puts more emphasis on the color differences between composite grays, where
C is lower than 50%. The goal of weighting is to reduce the importance of the gray balance for
very dark grays. These dark grays errors are difficult to handle and are usually printed with black
ink. This weighting definition is in accordance with the IDEAlliance G7 specification.
Learn about color differences
Chapter 9 - Print what you expect
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