[argyllcms] Re: What colorchart I should buy?

Davide wrote:

Hi all, first of all Happy New Year!


Happy New Year :-)
I just take a look into colorcharts to profile my DSLR camera, and I found that Colorchecker SG from X-Rite it's one of the most popular. Reading around I discovered that Xrite doesn't provide the reference file for that chart..
In "ref" dir of Argyll I found it but I think it doesn't came from Xrite directly but it's a user contribution right?
Argyll contains only the .cht file (i. e. the test chart recognition template) but no .cie file (CIELAB or XYZ measurement values) for the ColorChecker SG.
At the moment, the only way to obtain XRite's reference file is to install one of the Xrite Profiling packages (e.g. ProfileMaker). You don't need a ProfileMaker dongle for this purpose.
At Graeme's urging [1] Thomas Kunz (XRite) announced that Xrite will publish separate reference files on their website soon -- see 
<http://lists.apple.com/archives/Colorsync-users/2009/Dec/msg00128.html>
To obtain the CIE values from the ProfileMaker installation, you can use eihter Argyll's logo2cgats and spec2cie tools or XRites MeasureTool (part of the ProfileMaker installation). ProfileMaker's MeasureTool will only export D50/2° data in demo mode, but that's what you need most likely anyway.
The spectral data file is located in the ProfileMaker subdirectory "Reference Files/Scanner/", filename: "Digital ColorChecker SG.txt". 

(Feel free to contact me off-list if you need further assistance).


I should consider buy that chart or some one else?
Free to give me suggestion :)
ColorChecker SG is a very good target for "general purpose" camera and scanner profiles as it contains a well-balanced mix of common, "natural" spectra.
Other (photochemical manufactured or printed) targets are often biased towards the manufacturing process they originate from and are less suitable to represent the spectral properties of natural scenes. Those targets can outperform ColorChecker SG in their special domains, but for general purpose camera profiles ColorChecker SG is the first choice IMHO. 

Klaus
[1] whole discussion: Thread "CororChecker SG CIE reference values (or lack of)" in <http://lists.apple.com/archives/Colorsync-users/2009/Dec/threads.html> and 
<http://lists.apple.com/archives/Colorsync-users/2009/Dec/thrd2.html>)

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