• From: "alberto.ferrante@xxxxxxxxxx" <alberto.ferrante@xxxxxxxxxx>
  • To: "argyllcms@xxxxxxxxxxxxx" <argyllcms@xxxxxxxxxxxxx>
  • Date: Thu, 19 Jul 2012 09:03:33 +0100 (GMT+01:00)

Dear Iliah and Edmund,
thanks for your replies. Following my replies to 
your questions.

> when you mean "profile" do you mean Raw or Jpeg? If 
Raw, which converter?

Raw; the converter is ufraw, an open source 
converter based on dcraw.

>First, how even was the light at shooting 
the target, what was the light 
>source, how much flare you are 
getting, how linear is the greyscale step wedge 
>on the shot, for each 
of 4 channels?

The light source was sunlight (in a day with clear sky 
with sun at the zenith). I used some black paper to shield the target 
from possible reflexes on the bottom and on the right and left. The 
illumination was even (I checked it on the images and, before taking 
the shot, with a Sekonic light meter). I do not see any flare in the 
image and I positioned the target to avoid glare as much as possible (I 
don't see any on the final image). I can post the picture of the target 
tonight when I get home, if required

>Second, what colour target are 
you using for creating the profile - how does it 
>warrant -qu for a 
LUT-based profile?

I am using the target made by Wolf Faust (coloraid.
As I mentioned already, I used it to profile other cameras in the 

> Third, how do you obtain the source rgb image for profiling? 
Is it through 
> ufraw in profiling mode?

Yes, through Ufraw, by 
setting the output as absolute colorimetric, 16 bit, tiff. With not 
color profile and linear base and output curves.

> Forth, why -al 
instead of -ax; if not a -G which is a much more stable solution?

tried them both, but with no good results.
In the past I tried all of 
the available profiling options and at the end I preferred the -al, but 
I am ready to change my mind if any other option works better!

Fifth, does ufraw allow for a linearization tone curves over all 4 
channels? If 
> not - ask them to implement this option. If they are 
unwilling, linearize 
> yourself. Linearity must be calibrated before 

Can you please give me some references about this? What is 
a linearization tone curve?

Thanks again!


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