[argyllcms] Re: Calibrating a digital photo frame

  • From: Frédéric Mantegazza <frederic.mantegazza@xxxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Mon, 17 Dec 2007 18:16:46 +0100

On samedi 15 décembre 2007, Frédéric Mantegazza wrote:

> If I can generate all patches, download them to the photo frame, and
> then display them in the right order during calibration process, it will
> be easier.

Ok, I make some tests, using dispread (with the new -C option, to call a 
script just waiting for a key pressed). I generated 100 patches with 
printtarg, downloaded them to the photo frame, and launched dispread...

The results are not very good, and I don't understand why. Actually, this 
photo frame's main default is its non-linearity; and it burns high lights. 
As Graeme said, it does not have any LUT, so all corrections have to be 
done with the color engine.

Once image are converted in its color space, they looks like better in the 
high lights, but the problem is now in dark areas: they are too dark, and 
there is a color shift (blue).

About conversion, I used jpegicc, from lcms project, but it does not seem 
to be a very good job: even with quality 100, the compression is really to 
much, and I see artefacts. I tried cctiff, but I need to convert images 
from jepeg to tif, than from tif to jpeg in order to download then in the 
photo frame. Is there a Argyll tool to convert jpeg files from one space 
to another?

Last question: do I have to specify a linear cal file with dispread? What 
if I does not give a cal file?



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