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[284] Difference between two colours in CIELAB
The following Delta E range illustrates how the values of Delta E may be interpreted for a specific
colour evaluation.
• Delta E smaller than 1 is not visible by the human eye.
• Delta E between 1 and 2 is visible through close observation.
• Delta E between 2 and 10 is visible at a glance.
PRISMAsync Print Server uses two variants of Delta E:
• Delta E 2000, △E00, the industry standard.
• Delta E 1976, △E76, based on a less complicated and accurate distance calculation.
△H (Delta H)
To indicate more colour difference information than the total colour difference Delta E, the hue
error △H (Delta H) is used.
You can imagine Delta H as which colour difference is left over when the lightness and the
chroma differences are ignored.
△L (Delta L)
△L (Delta L) is the lightness difference between the two colours. |ΔL| is the absolute value of △L
(Delta L).
The weighted |∆L| puts more emphasis on the colour differences for light greys, where the K
value is lower than 50%. The goal of weighting is to reduce the importance of the lightness factor
for very dark greys. The human eye usually does not identify errors in the very dark grey colour
area. This weighting definition is in accordance with the IDEAlliance G7 specification.
L
a
-
b
-
∆E
b +
a +
Chapter 10 - Print what you expect
Learn about colour differences
263
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