[argyllcms] Re: Hutchcolor targets

  • From: Roger Breton <graxx@xxxxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Sat, 15 Sep 2007 13:52:18 -0400

Daniel,

Thank's for the Zipped file.

I think what we're seeing here is an abrupt change in the blue region of the
Granger rainbow. It is as though the Nikon scanner was unable to render
smooth transitions from unsaturated blues to saturated blues. It could be
the consequence of a number of things. I just got a Nikon Coolscan 5000 and
have not had the chance to do those experiments here yet. But if I come up
with similar results to yours on my unit, I have to confess that it will
prove a big disappointment.

Could you post a TIFF of the regular IT8.7/2 so that we can see the
difference?
 
> This zipped .tif of a Granger Rainbow has my scanner profile assigned to it:
> 
> http://www.geocities.com/d_chaffe/grangerrainbowcopy.zip
> 
> It's a LUT-based profile of a Nikon scanner using the Hutchcolor
> target and set on -qh.  The average and peak errors reported at the
> end seemed okay - they were near 1 and 5.  I tried a regular IT8
> target on the same scanner, as well as a reflective target on an Epson
> scanner, and got a fairly similar "eye" shape in the blues on a
> Granger.  I don't really know enough to judge whether what I see in
> the rainbow is a concern or not.
> 
> Daniel
> 

Roger Breton 



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