[argyllcms] Re: i1 Photo rebate or i1Beamer upgrade

  • From: Geert Janssens <info@xxxxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Wed, 2 Apr 2008 10:05:14 +0200

Great !

This helps a lot. It seems I don't need the special i1 Beamer upgrade at all.

I think I can manage to install the device in such a position that it 
correctly captures the colours on screen in other ways. And for the 
calibration, there is a cap that comes with it with a white spot in the 
center, so that should work ok.

Thank you for the extra info !

Geert

On Wednesday 2 April 2008, Graeme Gill wrote:
> Geert Janssens wrote:
> > Questions:
> > - I suppose this complete darkness can also be recreated in other ways by
> > carefully covering the lens opening of the i1 Photo ?
> > - Is this spectro calibration standard procedure before profiling ? I
> > mean, does ArgyllCms do this also and is it required ?
>
> Yes, it's standard to calibrate the device before each use. In emission
> measuring mode, it's usual to block the sensor using the white
> reference, and calibrate the black level.
>
> What I've done is simply calibrate it this way, and then put the
> device in position. If you need to stop and start the
> software, use the -N flag to avoid re-calibration while it's
> in position. [ The previous calibration for that mode
> is stored in a file, and will be read in each time the software starts. ]
>
> > - How can I point my spectro to the screen center using Argyll ? Does it
> > also have some software trick for this ? Or are there some independent
> > tools I could use for that ? Note that I am limited to linux, so using
> > X-Rite's software isn't really an option.
>
> It's really just a matter of making sure that the instruments field of view
> is filled by the screen, and that it isn't seeing it's own shadow. If you
> are operating with more than one display (so you can operate the
> software without needing the display being measured), you can fill the
> display being measured completely, using the -p parameters (e.g. -p 0,0,10
> will usually do it).
>
> > Also, imagine I manage to get the beamer/screen combo profiled. I suppose
> > such a setup is even more susceptible to influences by ambient light ? I
> > can't fully darken the room whet the beamer, so outside weather
> > conditions will definitely play. In the end, I may have to go for
> > Frédéric's procedure, and profile the beamer only.
>
> Yes it will be influences by ambient light, and it will also be influenced
> by stray light from the screen itself being reflected back from the
> surrounding environment. This might be a reason for not filling the whole
> screen with the test colors. But if the screen normally has a level of
> ambient lights, then there is nothing wrong with capturing the way it
> appears, and going from there.
>
> Graeme Gill.



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