Darktable LUT tool: chart not loading


I’m having trouble loading the reference file for an IT8.7/2 card in darktable-chart.

I tried multiple reference files (i.e. ones that can be found at http://www.targets.coloraid.de) to check what works and the only kind that actually registers and makes the grid and values appear in the tool is ColorCheckerPassport.cht (found in an article about profiling a camera here at pixls.us).

Some context:
OS: Windows 10
Target: IT8.7/2 from www.greywhitebalancecolourcard.co.uk

Best regards,

Hi @Alex_K and welcome!

I have a faint memory of something similar happening to me,
a couple of years ago… Something about number of columns
in header not as expected or not corresponding to actual
number, &c.

I’ll dig down into my old notes & will get back here as soon as I
find a valid clue…

A little later…: more info here

Have fun!
Claes in Lund, Sweden

Hi @Claes!
Thank you for the welcome :slight_smile:

I’ve tried the data that worked for Roger and it doesn’t for me.
I take it the file extension is irrelevant.

Is there a way to see the tool’s log on Windows? Knowing how exactly it errors out would be helpful.

??? Please elaborate.

File extension was the first thing I tested. Txt or cht - the tool loads color checker reference data correctly and doesn’t load the ref file provided by the target maker.

If you want, I could see how your RAW file
behaves here, on my machine. I am on Linux.

Well, my goal is to create a bunch of color look ups in various lighting conditions to emulate S5Pro behavior on a Z6. I have the test files converted to the format the LUT tool requires and the only obstacle is telling the tool what’s what :). If you could try and load the reference file for my target and see if it loads on Linux or what error it throws it would clarify things. I don’t even need ultimate accuracy so any functioning chart data for this layout would do. Maybe one of those IT8.cht files I see in tutorial screenshots would do the trick… (although I don’t know if there’s something different about their format). For some reason Color Checker chart works and it’s a different format.

ps: I on a phone atm