[Openicc] review of new ProPhoto-RGB profile

[Kai-Uwe Behrmann]

Am 23.03.12, 12:04 -0600 schrieb Chris Murphy:
> On Mar 23, 2012, at 10:13 AM, James Cloos wrote:
>> "KB" == Kai-Uwe Behrmann <ku.b at gmx.de> writes:
>>
>> KB> find attached a newly created ICC editing profile for review. It was
>> KB> created with ProPhoto primaries and a gamma of 1.8 like the original
>> KB> one.
>>
>> I used iccToXml to take a look at it, and got this fragment:
>>
>>    <curveType>
>>      <TagSignature>rTRC</TagSignature>
>>      <TagSignature>gTRC</TagSignature>
>>      <TagSignature>bTRC</TagSignature>
>>      <Curve>
>>         461
>>      </Curve>
>>    </curveType>
>>
>> The last profile you posted had a 256-element vector there.
>>
>> Is that a short-cut for a well-known curve?
>
> Same curve type as Adobe's ProPhoto RGB. However I'm seeing a difference in primaries and white point. Probably not big differences, but...
>
> Adobe's version of ProPhotoRGB:
>
>      <TagSignature>wtpt</TagSignature>
>      <XYZNumber X="0.96420288" Y="1.00000000" Z="0.82489014"/>
>
>      <TagSignature>rXYZ</TagSignature>
>      <XYZNumber X="0.79766846" Y="0.28804016" Z="0.00000000"/>
>      <TagSignature>gXYZ</TagSignature>
>      <XYZNumber X="0.13519287" Y="0.71188354" Z="0.00000000"/>
>      <TagSignature>bXYZ</TagSignature>
>      <XYZNumber X="0.03134155" Y="0.00009155" Z="0.82490540"/>
>
> Review version of ProPhotoRGB:
>      <TagSignature>wtpt</TagSignature>
>      <XYZNumber X="0.96429443" Y="1.00000000" Z="0.82510376"/>
>
>      <TagSignature>rXYZ</TagSignature>
>      <XYZNumber X="0.79771423" Y="0.28805542" Z="0.00000000"/>
>      <TagSignature>gXYZ</TagSignature>
>      <XYZNumber X="0.13516235" Y="0.71186829" Z="0.00001526"/>
>      <TagSignature>bXYZ</TagSignature>
>      <XYZNumber X="0.03132629" Y="0.00007629" Z="0.82489014"/>
>
>
> Is there correction for flare in these values?

I just picked the values from ROMMRGB.pdf and lcms generated the profile 
matrix from these below values.

http://www.color.org/chardata/rgb/rommrgb.xalter:

Chromaticity co-ordinates of primaries:
R: x=0.7347, y=0.2653, z=0;
G: x=0.1596, y=0.8404, z=0;
B: x=0.0366, y=0.0001, z=0.9633.

> Chris Murphy

kind regards
-- 
Kai-Uwe Behrmann
www.oyranos.org