[argyllcms] R: Re: R: Re: Neutralize Grey Axis
- From: "realman10@xxxxxxxxx" <realman10@xxxxxxxxx>
- To: <argyllcms@xxxxxxxxxxxxx>
- Date: Tue, 11 Jan 2011 19:46:45 +0100 (CET)
Hi Klaus, I did as you said. I picked up a paper with a b value =8, i.e bluish
in terms of Fine Art.
The profile I obtained is in fact slightly warmer than the "standard" one. In
practice on a series of gray patches it produces b values that are 1 point
higher.
The black and the white point are protected and not messed with, so that is
good news.
I would like to have a stronger effect and I believe I have to follow the
device link strategy. As I said I am learning...where can I start if I want to
understand how to manipulate device link profiles? A good suggestion is
welcome...
Michele
>----Messaggio originale----
>Da: lists@xxxxxxxxxxxxxxxxx
>Data: 11/01/2011 15.45
>A: <argyllcms@xxxxxxxxxxxxx>
>Ogg: [argyllcms] Re: R: Re: Neutralize Grey Axis
>
>realman10@xxxxxxxxx wrote:
>> colprof -iD50_1.0.sp -o1931_2 -f -qh -ds:n -dw:.345669:.358496 -da:100 -db:
18 -
>> dl:170 -df:1.5 -df:.345669:.358496 -S"sRGB.icm"
>>
>> is that something I can use as such or does it need to be adapted to the
>> actual paper white and L that he is using?
>
>D50 is most likely the illuminant you are looking for, but you can vary
>the effect of the FWA compensation by using D50-like illuminants with
>more or less UV (D50_0.0.sp ... D50_3.0.sp files in Argyll's "ref"
>subdirectory)
>
>You can simplify the command if you use predefined viewing condition (-d
>pp, pe or pc) and just overwrite the adapted white point chromaticity
>(e.g. "-dpp -dw:.345669:.358496") x=0.345669, y=0.358496 are the xy
>values for D50 (respectively a* = b* = 0 under D50) so this is most
>likely what you are after. You can calculate chromaticity coordinates
>for other adaptation colors using Bruce Lindbloom's Color Calculator
><http://www.brucelindbloom.com/index.html?ColorCalculator.html> if required.
>
>But as Gerhard mentioned and Graeme confirmed, changing the CIECAM
>adaptation chromaticity does not affect the gray balance of the
>perceptual intent essentially, so it might be better to replace it by
>-taa (Absolute appearance intent) as Graeme suggested. There's no gamut
>mapping in the absolute appearance intent however. If i got it right,
>the only way to get both gamut mapping and adaptation to a white point
>other than paper color in Argyll seems to be using device link profiles.
>
>Klaus
>
>
>
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