[argyllcms] Re: Fwd: Camera calibration using Silverfast DC Pro target

  • From: Jörg Rosenkranz <joerg.rosenkranz@xxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Thu, 20 Aug 2009 09:14:48 +0200

2009/8/20 Graeme Gill <graeme@xxxxxxxxxxxxx>

> The target is certainly rather reminiscent of the ColorChecker SG, although
> various details are different.
>
> I've created a .cht file and put it at: <
> http://www.argyllcms.com/LaserSoftDCPro.cht>,
> and checked it out against your photo. (I think SilverFast is the scanner
> software,
> while the charts are all called LaserSoft).


Many Thanks!
Yes you are right, the company is called LaserSoft. They are selling these
targets at the moment cheap at eBay Germany.

How do you get the CIE reference file ? Is it provided with the chart ?
> Can you send me an example ?


This file can be found at the SilverFast site:
http://www.silverfast.com/it8calibration/en.html?get_reference=D050311
I have uploaded my RAW file of the chart to
http://dl.getdropbox.com/u/1784049/DSC_2549.NEF


> There is, but it's a bit of an art. Recently I've been creating them
> by hand rather than trying to build them up from the raw recognition
> data (the scanin -g output).
>

I suspected it after reading the doc comments about scanin -g and the CHT
format ;-)

I have tried your CHT file using the steps from Pascal's site:
http://blog.pcode.nl/2008/11/15/color-profiling-your-own-dslr-redux/
The result looks good but I don't have the target here to compare it side by
side. The output of colprof was:

Find white & black points
White point XYZ = 0.794700 0.823400 0.711300
Black point XYZ = 0.006200 0.006400 0.005800
Fixup matrix for white point
After white point adjust:
Matrix = 2.347767 0.568693 0.170324
         1.025433 2.564108 -0.425191
         0.038665 -0.511254 3.025098
Done gama/shaper and matrix creation
Profile done
profile check complete, peak err = 14.241324, avg err = 5.468656

Thanks again,
Joerg

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