Re: Colorimetric Accuracy in the Field
Re: Colorimetric Accuracy in the Field
- Subject: Re: Colorimetric Accuracy in the Field
- From: Iliah Borg <email@hidden>
- Date: Wed, 05 Jun 2013 11:15:13 -0400
On Jun 5, 2013, at 11:06 AM, Rich Wagner wrote:
>
> On Tue, 04 Jun 2013 13:18:48 -0400 Iliah Borg wrote:
>
>>>> 3. Use dcpTool. (http://dcptool.sourceforge.net/Introduction.html) This command-line driven software can decompile binary format DNG profiles into XMP, compile XMP files into new compiled DNG profiles, make a profile "invariate" (an invariate profile won’t cause changes in tint when you make adjustments to exposure settings), and untwist a profile. (An invariate profile won’t change color when you adjust exposure settings, but still has hue twists embedded within it. Untwisting a profile removes all hue twists completely. See http://dcptool.sourceforge.net/Hue Twists.html)
>>
>>
>> With dcpTool you can reduce the "DNG profile" (DNG Camera Profile, DCP) to a simple matrix (ColorMatrix), however in ACR/LR white balance is still applied using ColorMatrix interpolation or extrapolation. Unless ad hock dcp is calculated for the light in the scene the result of interpolation/extrapolation is unpredictable in terms of colour.
>
> Iliah,
>
> Of course, DNG profiles can be created from a single illuminant with both the ColorChecker Passport software and the DNG Profile Editor, where both matrices end up identical.
>
> dcpTool can do a lot more than just reduce a DNG profile to a simple color matrix.
I know. I just do not see it solving colorimetric renedering.
> I'm particularly looking for feedback from people who have been using this tool
I do.
> , as appropriately modified DNG profiles would appear to effectively deal with many of the complaints about LR/ACR and colorimetric accuracy.
Addressed it. Apart from being far from colorimetrically accurate dcp profiles with extra parameters introduce additional noise and artifacts (smoothing of LUTs leave a lot to be desired).
CC24 is too small for any colorimetric accuracy anyway.
--
Best regards,
Iliah Borg
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