[argyllcms] Re: RGB Printer Profiling / Issues with Blacks and Shadows
- From: Andreas Hebeisen <fotografie@xxxxxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Fri, 5 Aug 2011 17:42:19 +0200
Graeme,
Thanks for your answers regarding my problem.
On 04.08.2011, at 11:23, Graeme Gill wrote:
>
> So you should be getting RGB black out from it.
OK. That's good to know.
So there is definitely no problem with the way I've created my profiles.
BTW: It's not just the blacks which aren't as black as they should be.
Every color seems to suffer from this problem. But I noticed it first in the
blacks.
Meanwhile I've found a reliable method to simulate the problem, without the
need to print.
If you like, I can send you two PDFs which show the evaluation image I'm using
but with the color corrections applied from Aperture using either the
eyeOne-iMatch or the ArgyllCMS-profile.
But they're pretty big (around 45Mb each), so I'll just send them if you really
want.
> At a guess there is something odd going on with the CMM. Perhaps the
> input profile black point is being treated oddly ?
Seems so.
But it can not be within Apples ColorSync CMM, because when I print from
Pixelmator using ColorSync, everything seems to be quite OK.
> (Not unusual
> when it comes to RGB/matrix profiles, and the various changes in the ICC
> spec. in regards to this aspect).
Hmm... Can't really follow, but sounds bad.
> What happens if you use the sRGB
> profile from the Argyll distribution as the source colorspace ?
I did try that too (along with other profiles).
Unfortunately, I'm not seeing the slightest change in the output.
Since it seems to bee a big secret which color space Aperture uses internally
before sending the files to the printer driver, one can only guess which input
profile would be best.
At the moment, I'm in the middle of another experiment:
I printed the targets from Aperture with no color management (instead of using
the Adobe Color Printer Utility) and will measure them as soon as they are dry
enough.
Maybe this will compensate the error?
I will come back with the results as soon as I get there.
Andreas
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