Profiling a camera with darktable-chart

@asn: Thanks a lot! Using this style is a much better starting point than native darktable settings. Also my pictures seem a bit oversaturated …

@priort: Thank you! Possibly I will try these in future with darktable-chart since I don’t own an own a color target

I can also convert the Adobe DCP file for you may take a day or two but you can test that too

Note that this is a profile for bright sunlight pictures, they don’t work really on other pictures …

4 posts were split to a new topic: local editing in RT

@priort: After playing a little more, now I am indeed interested in Adobe DCP files. As far as I understand, i cannot use it in darktable, but in RT, correct?

Correct, RT can directly use a DCP file.

Thank you Mr Brown, I’m totally new to darktable.
Creating a custom ICC profile is a lengthy but worthy process.
I’m sure to try it soon with the help of your detailed instructions.

I have read elsewhere that RAW is “never” color-balanced, by definition, regardless of camera manufacturers. I was just wondering if that is also your experience? IOW, there would be no need to color-balance when shooting RAW. When shooting JPEG, yes, it’s a different story.

Interesting post that explains why this process can be misleading because you can never know the exact spectrum of the illumination:

Unless you have all the relevant spectral measurements , a colour rendition chart should not be used to perform colour-correction of camera imagery but only for white balancing and relative exposure adjustments.

Have been following this well written instructions until starting darktable-chart. When trying to load the cht-file from Argyll for my SpyderCheckr24 dt-chart reports “Error parsing CHT file, (parse_cht 376)”. I have verified against the CHT definition on the Argyll website and tried to manually apply some adjustments to the file, but it still does not load. Any idea what this error code means or why the Argyll-CHT-file does not load?

Moinchen @hoodoos and welcome.
If you use the forum’s search facility
and enter cht as search phrase you
will find some info.

Have fun!
Claes in Lund, Schweden

Finally got it solved. dt-chart is really picky about white spaces, I had already worked on removing double empty lines and double spaces between values, but there was still some additional white space at the end of lines and beginning of lines.

But now a completely different question: The styles generated by dt-chart employ a number of display-referred modules, that do no longer belong to the new v3 scene-referred standard workflow. Any thoughts of the experts on this? Will there be a new approach for camera profiling following the new approach of dt?

I guess you are looking for this: https://youtu.be/EteAhSN9W8s

Just use the LUT part of what you just generated and not the bade curve. Apply the LUT after filmic and you’re good to go.

As i recall the spyder had to be oriented with white top left whereas colorchecker is white bottom…left…then the files cht and cie should work…

Its not exactly the same the …new feature tweaks the channel mixer to improve any color deviation that has been created from wb and the input profile. Darktable chart created a style with a lut and tone curve that could be used in two ways…1 against a color chart…like the reference for the new method…but you could also use the in camera jpg as a reference to try to achieve color matching to the jpg…now with scene referred I think the recommended way would be to keep the lut and drop the tone curve…

Yes, darktable-chart is no longer the preferred method – the new approach is to use the color calibration module:
https://darktable-org.github.io/dtdocs/en/module-reference/processing-modules/color-calibration/#extracting-settings-using-a-color-checker

just to clarify – color calibration is for correcting colours under a particular illuminant against the reference values for the colour charts – ie. standardising the colours. It is an altermative to producing an ICC matrix profile for your camera.

darktable-chart can also be used for matching colours between JPEGs – in that case, the JPEG you are matching against is already a display-referred image, and so using display-referred modules probably makes sense in that case.

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Yes, my primary target is less to calibrate for the correct color according to a color chart, but rather to make the Canon picture profiles available that provide different color matrices from RAW to JPG. While using Lightroom I never used the Adobe standard profile (which to my understanding is the darktable standard input color matrix) but rather the best fitting Canon color profile. So ideally these should be available as input color matrix. But applying the Color LUT created by darktable-chart at the end of the pipe is a possibility. Thanks for the input.

Some styles from darktable chart to try Do you want a straight out of camera JPEG style in darktable? Here we help each other - #51 by Peter