Darktable and X-Rite ColorChecker Camera Calibration Software

I wrote a simple bash script to run the two ArgyllCMS programs needed to produce a camera icc file from a target shot of a ColorChecker:

#!/bin/bash

scanin -dipn -v -G1.0 -p $1.tif /usr/share/color/argyll/ref/ColorChecker.cht /usr/share/color/argyll/ref/ColorChecker.cie
colprof -v -am -u -C"No copyright, use freely." -O$2.icc -D$2 $1

Use it something like this:

$ ./cam.sh <infilename_withoutextension> <outfilename_without_extension>
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@MStraeten Martin thanks for sharing the links…all high quality…what is your opinion on processing the target to produce a DT Style vs an ICC file?? So I guess Darktable chart vs Argyll??

In my experience the icc way is better if you want to get ‚real‘ colors, the dt chart style approach is better to match camera presets. i never was able to get satisfying results using darktable chart with referencing the cie file …

The dt chart approach requires the use of tonecurve to get proper colors and so it‘s not the best way if used in a filmic workflow (out of the box RAW rendering not up to JPEGs - #67 by MStraeten)

Thanks for your perspective. I appreciate you taking the time to reply…

with Argyll you can use DCamProf http://rawtherapee.com/mirror/dcamprof/dcamprof.html to fine-tune or make a better ICC Profile

Did you ever just get the DCP files from adobe and try to convert them to icc…you can do this with dcamprof??? Might be worth seeing how that compares to the DT ones and you can add curves and lut etc to tweak the profile??

@priort, no, I didn’t try that. @Morgan_Hardwood kindly offered to make 5DSR DCP and ICC profiles, which would be available to all RT and dt users. Now Summer is pretty much here, I’ve done the outdoor shots and I’ve asked Morgan if he’s still ok to make these profiles, if yes then I’ll do the bulb shots and upload everything.

You can get the adobe ones free. You just install the DNG converter software and you have the whole Adobe library. You can delete the software after if you have not use…The work strait away in RT…conversion
of those to ICC is a two step process….dcamprof is the best tool I am aware of for that.

Best

Todd

I tried this for my two cameras, D7000 and Z6, made a LUT ICC from the Adobe Standard DCP for each. D7000 worked fine; Z6 not so much. I didn’t dig into the possible faults…

I must admit I played with it more in RT as you can use them directly and I could enable parts of the profile ie the tone curve and the lut. I think it gave better skin tones in the images I tried
but it wasn’t a comprehensive evaluation…

how you did that? Can you please explain the process

Explained here: Help converting dcp to icc using dcamprof - #7 by ggbutcher

Note that, instead of -p matrix in the second dcamprof invocation, you would use -p xyzlut

dcamprof can be found here, source code: GitHub - Beep6581/dcamprof: DCamProf is a free and open-source command line tool for making camera profiles, and performing tasks related to camera profiles and profiling.. dcamprof is rather easy to compile, so I’ll leave that up to you…

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etc. Thanks for the suggestion Todd but it seems it’s the adobe DNG data that’s used in darktable by default already. See first Aurelien P post on Feb 24 here -

Perhaps but likely just the matrix values…you can produce an ICC with several modifications including a LUT and tone curve version….

You over-estimate my capabilities!

Many experts here, can someone please make a detailed tutorial for mortals like us please!

Morning, @Rajkhand,

A good start is to search this forum.
Enter search word

torger

Have fun!
Claes in Lund, Sweden

The post I linked to above is slightly off, should be Help converting dcp to icc using dcamprof - #8 by ggbutcher, post 8, not post 7…

It contains exactly what information you need to do the conversion. I don’t know your particular level of ‘expert-ness’, but you’ll need to know how to use a command line shell, and you’ll need to know how to compile a program from its source code. Oh, and the simplest way to get the source code is to clone it from GitHub - Beep6581/dcamprof: DCamProf is a free and open-source command line tool for making camera profiles, and performing tasks related to camera profiles and profiling., but even that will require some study if you’ve not used git. After you get that down, the two commands in the post do the following:

  1. Convert the DCP file to a .json file. This is the human-readable format dcamprof uses as an intermediary between profile formats.
  2. Use the .json file from Step 1 to make the ICC profile.

We’re all mere mortals here; all of us have done different things. If your sum experience with computers has been with “mouse-click” applications, this particular process will be daunting, no doubt. But dive in, start with the git clone to get the source, and where you run into problems, just come back here and post. We don’t bite, too hard, anyway… :smiley:

Thanks for your advice, I use a hackintosh and there is a pre compiled binary for DCamProf so no problem there and I am good at using the command line where clear instructions are given. But I am not good at understanding the maths & science of making an icc or DCP profile. In short I can follow the steps.

I also recently used the X-Rite program to make an icc profile but when used with DT the pics are dark even after applying the base curve.

My quest is to make as Color accurate profile as possible with Color checker passport.

Thanks.

Good, then it should go well for you…

I’m rather new to all this color management business also, and I have found the dcamprof doc page to be the best writing on the topic:

http://rawtherapee.com/mirror/dcamprof/dcamprof.html

I still don’t understand half of it, but I keep coming back, finding I understand a bit more every time.