Re: Color Measurement
Re: Color Measurement
- Subject: Re: Color Measurement
- From: Robin Myers <email@hidden>
- Date: Wed, 15 Jul 2009 13:30:03 -0700
Just as the scale changes in going from dE 1976 to dE 2000, the
tolerance range also changes. Where 1 dE 1976 was "roughly" assumed to
be a Just Noticeable Difference (JND), now that number should be about
0.5 dE for a JND in dE 2000. As the scale changes, so does the
interpretation.
Robin Myers
On Jul 15, 2009, at 12:58 PM, Mike Eddington wrote:
2.increase your tolerances to account for instrument
differences, or perhaps use dE2000
This should produce no improvement. Changing the metric will
not improve the inter-instrument agreement. It would be like
changing from an Imperial to a metric tape measure, the units
change but the item being measured does not.
Correct, it would not improve instrument agreement per se, but its not
exactly like changing units on a tape measure, where one unit is
always
equal to x other units. My contention is that many "measured"
differences in dE76 are less significant perceptually, and since
dE2000
more closely correlates with visual perception, differences between to
measurements are often less. So your "inch" (dE76) often looks more
like
a "centimeter" (dE2000). Like the examples below:
L* a* b* L* a* b* Delta E Delta E
2000
24.2 -0.55 -2.69 25.3 -0.5 -2.1 1.24924
0.963587877
54.34 -29.52 -48.79 55.3 -30.4 -47.5 1.833058
1.101827061
48.64 65.89 3.22 49.2 65.1 2.5 1.20669
0.668108822
86.38 -3.03 83.52 86.7 -3.5 82.2 1.437254
0.451074496
Mike
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