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Learn about colour differences
△Ch (Delta Ch)
Close to the grey axis, in other words for near neutral colours, the usage of Delta H is not
appropriate enough. Instead, the usage of the △Ch (Delta Ch) metric is proposed.
The metric that is called chromaticness can reveal grey balance errors.
The weighted ∆Ch puts more emphasis on the colour differences between composite greys,
where C is lower than 50%. The goal of weighting is to reduce the importance of the grey balance
for very dark greys. These dark greys errors are difficult to handle and are usually printed with
black ink. This weighting definition is in accordance with the IDEAlliance G7 specification.
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Chapter 10 - Print what you expect
L
∆L
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a
b
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b +
a +
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