Doubts about the creation of a camera sensor profile icc file in DT 3.4.1

**My context: Ubuntu 20.04, Darktable 3.4.1. In preferences --> processing I selected “scene-referred” and “modern”
**
I would like to prepare an ICC file to profile my camera sensor by means of xrite Colorchecker Passport.
Therefore I read the article of Andreas Schneider on this subject (updated on: 2019-06-18) in
https://pixls.us/articles/profiling-a-camera-with-darktable-chart
with extreme deliberation but… I’m somewhat lost.
In the mentioned article Andreas says:

You then open the RAW file in darktable and disable the base curve and all other modules which might be applied automatically! You can leave the Orientation module turned on. Select the standard input matrix in the input color profile module and disable gamut clipping. Make sure “camera white balance” in the white balance module is selected. If lens corrections are automatically applied to your JPEG files, you need to enable lens corrections for your RAW files too! Only apply what has been applied to the JPEG file too.

For my configuration I was left with the following modules enabled:

  • Output Color Profile

  • Input Color Profile

  • Lens Correction (Optional)

  • Crop & Rotate (Optional)

  • Demosaic

  • White Balance

  • Raw Black/White Point

Instead my ‘beloved’ configuration (options “scene-referred” and “modern”) automatically starts both “White Balance” and “Color calibration” modules which are designed to work together, the output of the former being the input of the latter (I know that, as explained by Aurelién Pierre in his article, it is possible to deactivate the “Color calibration” module and only use the “White balance” module in the old way. But this for me could be only an exception not the rule).

To put it in a nutshell, my question is: to create the ICC file according to Andreas’ procedure am I supposed to enable the “Color calibration” module adding it to the modules listed by Andreas?

Ciao
Vittorio

I’m not familiar with the specific darktable tool for making camera profiles, but what I do in making my profiles with Agyll and/or dcamprof is to make a target shot that is presented to the profile algorithms with only demosaic and whitebalance applied. So, cutting out all the other tools is IMHO prudent. What I don’t understand reading Andreas’ instructions is that the standard input matrix is to be enabled. I’ve been making profiles from target shots without any color conversion using the input and output profiles and they come out performant.

The goal is not to present a visually pleasing image for profile construction; think of it more as presenting camera measurements for use in characterizing the camera.

I don’t think you want color correction/balance/anything when trying to make an input profile.

What version of DT are you on…if dev you can calibrate to your passport right in DT. Its not an icc but correction via offsets made to the channel mixer to bring your WB and current input profile to be a closer match to your color chart. Then you can save this as a preset…

1 Like

Is he making an ICC or using DT chart…I can’t recall. I know that one way to run of DT chart is a match against a jpg and that is why you leave the input color profile as it would normally be applied. In that case its making a lut in the color lut module and a tone curve…

1 Like

@victor50
He is not creating an ICC but a Darktable style with a tone curve and a LUT in the color lut module…

This is the traditional way in DT for ICC
https://tomassobekphotography.co.nz/articles/create-camera-input-profile-with-ColorChecker-Passport.php
How to address the new color calibration module and WB if you are using the modern workflow someone would have to comment.

THe next release of DT won’t create an ICC but it will do colorchecker calibration…that process is described here

https://darktable-org.github.io/dtdocs/module-reference/processing-modules/color-calibration/

3 Likes

I’m on 3.4.1.

Okay so you won’t have that feature yet…I think it will be in the next release. You can find dev builds in the Master Branch here if you wish to experiment
From the install tab of the DT website


https://software.opensuse.org/download.html?project=graphics:darktable:master&package=darktable
Choose your method to install