Re: Eizo Color Navigator
Re: Eizo Color Navigator
- Subject: Re: Eizo Color Navigator
- From: Steve Upton <email@hidden>
- Date: Thu, 1 May 2008 11:02:22 -0700
At 10:14 AM -0400 5/1/08, Mike Eddington wrote:
>>>The target is basically RGB values thrown through the monitor
>>>profile to derive a reference, then it compares that to measured values.
>>
>>That is not exactly correct.
>>
>>The monitor validation procedure uses one of two methods, depending on the software package:
>>
>>1) It starts off with a list of RGB numbers, looks up their corresponding Lab values once the monitor profile is assigned to them, registers the Lab values read by the colorimeter from the monitor for each patch, compares the measured Lab values to the Lab values expected from assigning the profile, and finally derives DeltaE values from the comparison;
>>
This method effectively only tests the 'proofing' part of the monitor profile and the calibration of the display. For a matrix profile there really should be no round-trip issues but for a LUT-based profile you could get stuff introduced into the test that doesn't necessarily reflect what is expected in the test. For testing the neutrality of calibration or the curves of each channel though, this is the way to go.
>>or:
>>
>>2) It starts off with a list of Lab values, converts them to the monitor profile, sends the resulting RGB values to the monitor, registers the Lab values read by the colorimeter from the monitor for each patch, compares the measured Lab values to the Lab values in the original list, then finally derives the DeltaE values from the comparison.
>
>Seems like the former method might give more accurate results, as a given Lab list might contain values not reproducible on a given monitor.
Agreed, but the latter method is best to see if the monitor profile will reproduce color accurately on the screen and to test compliance with a reference data set (whether chosen to be in-gamut only or not). I suppose it is necessary if the native gamma of the display is kept constant in the profiling process. The profile will be required to see if the tone curve of the display is controllable...
In summary, you really need both to effectively test a display's calibration & profiling.
Regards,
Steve
________________________________________________________________________
o Steve Upton CHROMiX www.chromix.com
o (hueman) 866.CHROMiX
o CHROMiX Maxwell live May 14. All your color, anywhere.
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