I have downloaded the new ISO profiles that are supposed to conform to
ISO 12647-2:2004.
In annex C of ISO 12647-2:2004, it lists "CMYK values for use in grey
balance patches" as the following values:
Quarter tone Cyan 25 Magenta 19 Yellow 19
Mid-tone Cyan 50 Magenta 40 Yellow 40
Three Quarter tone Cyan 75 Magenta 64 Yellow 64
If you lookup the LAB values of these percentages using either absolute
or relative colorimetric rendering intent, you will see that the
mid-tone and quarter tone have negative A* values and near zero B*
values whereas the paper and has a near zero positive A* value and a
negative B* value. Tints of Black only that have the same Luminance
values as the grey balance patches have A* and B* values much more
similar to the paper than that of the gray balance patches.
These values do not seem correct. Am I understanding this correctly?
Thanks,
Abe Hayhurst
We Do Graphics, Inc.
1150 N. Main St.
Orange, CA 92867
714-997-7390
abe(a)wedographics.com
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