[argyllcms] Re: Gamut mapping problems in 1.1.0

2009/11/9 Klaus Karcher <lists@xxxxxxxxxxxxxxxxx>:
> Martin Weberg wrote:
>>
>> I did the following conversions. No tiffgamut used.
>>
>> 1. collink -G -ip -cmt -dpp ProPhoto.icm ISOcoated_v2_eci.icc devlink.icc
>> 2. In Photoshop I converted Bill Atkinson's Lab Test Page to
>> ProPhotoRGB colour space.
>> 3. Then, conversion cctiff -ip ProPhoto.icm -ip ISOcoated_v2_eci.icc
>> rgbinfile.tif cmykoutfile.tif
>> 4. and cctiff devlink.icc rgbinfile.tif cmykoutfile.tif
>>
>> The whole image from step 4 is really desaturated compared to 3.
>
> That's consequential. In step 1 you create a gamut mapping that compresses
> the whole, huge ProPhoto space into ISOcoated_v2. In step 3 you use the
> precalculated gamut mapping of ISOcoated_v2 to compress a much smaller gamut
> (AFAIK something like the Pointer space) to ISOcoated_v2. Step 3 gives you
> more saturation, but clips everything outside the Pointer space.

True, true... So, I used tiffgam on the whole image.

1. tiffgamut -pj -cmt ProPhoto.icm rgbinfile.tif
2. collink -Grgbinfile.gam -ip -cmt -dpp ProPhoto.icm
ISOcoated_v2_eci.icc devlink.icc
3. cctiff devlink.icc rgbinfile.tif cmykoutfile.tif

Now, the image is much better, but I still lack red/orange.

Martin Weberg

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