Wilson,
I gave it a shot a while ago for M9 DNG files Lightroom recompressed, and thus CaptureOne can’t interpret correctly. Thankfully, I had switched to CO quickly after I got the M9, so not too many pictures were affected and I didn’t need to reprocess all of them, anyway.
I used a standard 24 patches ColorChecker and the above mentioned ArgyllCMS software:
http://www.argyllcms.com/For reference: I called the TIFF file necessary to create the profile “ColorChecker.tif” and saved it in my home folder, inside a subfolder called “LeicaM“. That is: ~/LeicaM/ColorChecker.tif. I’m on OSX.
1) First, you need a “linear” TIFF of your DNG file for creating an ICC/ICM profile. In CaptureOne, open the ColorChecker photo and select “No color correction” in the Base Characteristics panel / “ICC Profile: Effects”.
2) In your output recipe, embed “camera profile” rather than sRGB or AdobeRGB. This makes sure colour values are transferred 1:1 from DNG to TIFF render, with no colour management in-between. Set output to TIFF 16bit.
3) In Terminal (again, Mac), use
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scanin -dioa -p ~/LeicaM/ColorChecker.tif /Applications/Argyll_V1.5.1/ref/ColorChecker.cht /Applications/ArgyllCMS_V1.5.1/ref/ColorChecker.cie
(all in one line) to create a diagnostic black-and-white preview. This will show whether ArgyllCMS recognised all colour patches of your ColourChecker card. If Argyll can’t properly outline all patches, reshoot the image.
This is my ArgyllCMS installation; on Windows or with other versions, the paths to ColorChecker.cht and ColorChecker.cie will be different.
4) If it worked, use above scanin line
without the -dioa -p switches. This will produce the file “ColorChecker.ti3”, an ArgyllCMS proprietary measurement format.
5) Now, to generate an ICC/ICM file CaptureOne can understand, you’ll need to use ArgyllCMS’s colprof program:
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colprof -ax -qm -kz -y -u ~/LeicaM/ColorChecker
This will produce a Matrix profile (rather than a LUT profile more suitable for scanners), with “normal quality” effort at doing so, looking to optimise for “minimal black”, and using no whitepoint extrapolation (because with only 24 patches on a standard ColorChecker, this would garble up your ICC profile quicksmart). The profile will be named “ColorChecker.icm”.
There’s loads of other switches you can use inside colprof, e.g. to set a profile name, but I found it easier to add metadata inside OSX’s ColorSync system utility.
Results were iffy and only applicable for
exactly the type of light I shot the ColourChecker in, preferably with exactly the same exposure, too (no exposure edits in post!). As I only needed it for a select few images I wanted to reprocess in CaptureOne, this wasn’t a biggie for me.
Should this quick-and-dirty experiment work for you, you will get better and more robust ICC profiles either by …
… using -qh (high quality effort) or -qu (ultra effort) with colprof/ArgyllCMS, which can take hours to compute and not produce that much better results …
… or shelling out for better ICC software such as basICColor’s “input”. Such software can use multiple targets to create more robust ICC profiles with dual illuminants rather than one – thus making the ICC profile more versatile in different light situations –, batch process, correct for spot colours etc., but they go for a couple of hundred Euro up to a few thousands a pop.
Another thing worth trying is other targets than the ColorChecker; Hasselblad e.g. suggests using a ColorChecker Digital SG chart, mostly as it has far more colour patches than the “old” ColorChecker – 140 vs/ 24. I guess that’s also what PhaseOne uses for creating their CaptureOne profiles. It’s sort of an industry standard for digital cameras.
Hope this helps, even should it make you hold back until PhaseOne releases proper Leica M Typ 240 profiles themselves
. Creating proper ICC profiles isn’t easy, quick, and often quite expensive. Adobe really has a killer feature with its DNG profiles supported by X Rite’s ColorChecker Passport software.
-Sascha
by Steinar12 » Thu Jul 21, 2011 6:41 pm 
Steinar
