[argyllcms] Re: A beginner's questions
- From: Leonard Evens <len@xxxxxxxxxxxxxxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Fri, 01 Feb 2008 16:04:48 -0600
On Fri, 2008-02-01 at 21:57 +0100, Luud Heck wrote:
> Thanks all for the feedback.
>
> I noticed the option to create a test image with timage. This shows
> the problem I'm have quite good.
>
> I uploaded an example here: http://www.heck.dds.nl/timage.tif
>
> Open this in a program that does NOT apply color management such as
> windows Picture and Fax Viewer.
>
> On the top you see what Photoshop does when using the profile
> generated with argyll for a daylight temperature of 6500K (as this
> matches what the colorvision software does). The bottom one is the
> same image without any color management.
>
> The problem is in the blocky character of the argyll profile. The
> colorvision profile is much smoother like the bottom one. As is the
> original profile as provided by samsung for this monitor. (I expect
> the same problem is bothering me under Linux.)
>
> Anyone even seen this before and knows what causes this?
I seem to have the same type of response you have with my display
profile using gimp under Linux.
It isn't produced by loading the vgct tag from the profile with xcalib.
But the blockiness you describe shows up when I activate the profile in
gimp 2.4. There seems to be a visual discontinuity in the green-magenta
direction at green about 60, but it doesn't show up when I just look at
the green channel alone. There is also some much fainter banding.
I've done some other tests which show gray scale banding, but it was my
understanding that this sort of thing was hard to eliminate with an LCD
monitor. I was going to come back at another time to see if I could
improve that by tweaking gamma. I don't know if the two phenomena are
related.
I hope someone can suggest what the problem is or else I will have to go
back to square one.
>
> Thanks,
> Luud
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