[argyllcms] Re: Gamma problems

  • From: David Garabana Barro <david@xxxxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Tue, 10 Nov 2009 01:34:29 +0100

O Luns, 9 de Novembro de 2009, Denis S escribiu:
> David Garabana Barro wrote:

> > I seems white is brighter on xrite's profile, and black is about the
> > same. So yes, it's noticeable.
> The reason that white look brighter could be in different color
> temperature IMHO, but I'm not sure. Let's wait if someone more
> knowledgeable try to answer your question.

But Color temperature is the same according to dispcal. I bet "-a" option was 
changing gamma and contrast taking in account my illumination. I have also 
tried with several illuminations. The higher the illumination, the lower the 
Definitely I think that was my problem.

> Yeah, I've just checked it. I didn't know you correct profile for
> ambient light, I completely forgot that there are such devices which can
> do this...  I usually just skip this step.
> BTW here is good explanation about Gamma, not sure if you read it
> already: http://www.argyllcms.com/doc/dispcal.html search for -g gamma

Believe me, I have read all the documentation you can imagine ;)
But color management is a hard field and my memory it's not the best in the 
world. I feel so embarrased for not realised before :(

> > How can I see the errors on an already created profile?
> Just set configured profile and issue dispcal -v -yc -r (not -R as this
> option is used for uncalibrated measurement).
> you'll see DE for color temperatures.

OK, I though you were referring to color representation errors. I know colprof 
gives you a summary when it ends:

profile check complete, peak err = 4.295966, avg err = 0.938010

but I don't know how to obtain that data with prebuilt ones...

> BTW you actually have very impressive DEs which are close to zero... if
> you look at info I've sent you in previous mail, you'll spot that error
> on my monitor is around 15 :)

cannot you adjust R,G and B cannon from CRT OSM?

> > Mine is a NEC FE950. It was a very good CRT, but it has its age...
> If believe to measured data you should have almost ideal colors. Wonder
> how do you use your monitor, are you in photography as I'm, or graphic
> or something else?

I really make a little bit of everything ;)
But yes, I use it a lot for photography processing. I'm also learning about 
that  :)

> Also if it's not hard for you, could you please check this post and tell
> if you have similar problem as described by me in this
> //www.freelists.org/post/argyllcms/Pink-tinted-cursor thread?
> I've seen that you also target monitor to 6500 and I feel that it's just
> me who have problems with cursor :P

I have no problem at all with cursor. It changes its colour when I change 

> Have a great day!

Idem, and thanks for your support! :)

David Garabana Barro
jabber & google talk ID:        david@xxxxxxxxxxxx
Clave pública PGP/GPG:          http://davide.garabana.com/pgp.html

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