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.
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
Hello,
I have used darktable-chart successfully some time ago. I think it was version 3.8 or 4.0. Now I want to create a new style with darktable version 4.2. but if I load the new exported pfm file in darktable-chart it is black. The old pfm file works fine. Do you know, where’s the problem with the new exported pfm files (everything is set right including the export in lab). Is there a know bug?
There was a window of time when it wasn’t working but it is now… bump up to 4.4.2 and it should be fine…
ups, excuse typo, my version is 4.4.2 not 4.2.
I think it has to do with the processing and upscaling… if you have them set to yes set them to no and retry… or the reverse… I think one of those settings results in the black file issue…
Edit : I will try at home on my PC and confirm but it seems not to be working again at least when I did a quick build and install…
Perfect! That’s it. Now it works again.
It works only if “allow upscaling” and “hight quality resampling” are set to “no”.
If one parameter is set to “yes” it will be black.
Thanks a lot!
Nice I thought I tried all combos quickly on my work PC and I kept getting black… I’m glad Zi was wrong on that point…happy profiling…
That setting in the camera pertains to the embedded JPEG. The profiling software should be working from the raw image.
I have no idea why the author would think that to be important to camera profiling. AdobeRGB and sRGB are output colorspaces, and the camera only uses them to make the embedded JPEG rendition. Oh, and to stick a tag in the metadata identifying the output profile used to make the JPEG. It doesn’t affect the raw data one whit.
I’ve done a lot of camera profiling with other software, I know what the input data should be.
But Glenn, the whole point of dt-chart is to produce a darktable style to match the jpeg. So isn’t the jpeg relevant? It’s not classic ICC profiling.
Just read the docs, that’s not profiling a camera.
Sounds good until “etc.”, then it’s now all this thing about making a style. Not familiar with that…
I just saw “Profiling a camera” in the thread title, and I have a pretty good grasp of that. Style-making, not so much. I’ll be quiet now… 
darktable 4.6 user manual - using darktable-chart 
@TimCoffey I’m not very well up on the dt-chart process, but I would think that AdobeRGB is what the dt-chart program is designed to deal with - the only difference from using sRGB (if the software was designed to) is greater gamut range, i.e. more points of reference.
In fact, in any situation, assuming that both the producer (i.e. camera) and consumer (i.e. software) are both using the same profile, the only difference in appearance between sRGB and AdobeRGB will be a slightly wider range of colours.
The only reason camera jpgs might look different in AdobeRGB is if the software isn’t reading and applying the correct profile/gamut/whatsit to display the file.
(happens often, at least on Windows.)
This is just my understanding - stand to be corrected!
Um… what article are you referring to? This thread is about using darktable-chart. See the link I posted for @ggbutcher above.
After reading more carefully through your last post, it seems you’re referring to the color calibration procedure to produce a preset for more accurate colours, using a 24 patch (usually) colorchecker This is not related in any way to darktable-chart.
No you can choose a jpg image if the style is to match the jpg or you can just choose the raw shot for strait color correction… just depends which you use as the reference…
Are you talking about using darktable-chart or color calibration?
Its important that @TimCoffey makes it clear which one he is talking about… In one case you are using a function in CC module to obtain a set of channel mixer settings to improve the match of the camera input profile and with DT chart you are making a tone curve and a lut into a style to either do roughly the same ie better match color to the colorchecker or to match color and tone to a matching jpg shot… in the former case you use the raw and in the later one you make a pfm file from the raw and/or jpg image and you tweak that to use LAB…
I do recall AP talking way back that if you were printing to use AdobeRGB for export as without calibration it would likely be close… I think that is what I recall but selecting that color space is not part of the calibration process used by these methods as far as I know
I think it is not darktable-chart that @TimCoffey is describing so this is the wrong topic for this …
Yes, I think I posted on the wrong topic! Sorry!