darktable queries

Software darktable
1

I’m experimenting with darktable v2.4.1 on Windows 8.1, and have some queries.

  1. When I start darktable-cli, it says:
(darktable-cli.exe:7820): Gtk-WARNING **: gtk_disable_setlocale() must be called before gtk_init()

Am I doing something wrong? Or is this a bug somewhere?

  1. When I use darktable-cli to process a raw file for which a sidecar XMP file exists, I may want to tell it to ignore the sidecar. How should I do that? Specifying an empty XMP file doesn’t work. Specifying an XMP file that contains just these three lines does work:
<?xml version="1.0" encoding="UTF-8"?>
<x:xmpmeta xmlns:x="adobe:ns:meta/" x:xmptk="XMP Core 4.4.0-Exiv2">
</x:xmpmeta>

But I hope there is a neater method?

  1. Output color profiles. The documentation at https://www.darktable.org/usermanual/en/color_group.html#output_color_profile says the user home directory for ICC profiles is “$HOME/.config/darktable/color/out”. For Windows, that is not correct. The tooltip correctly says it is “USERPROFILE\AppData\Local\darktable\color\out”.

  2. There seems to be no method to tell darktable that I keep my profiles in a particular directory. Instead, I have to copy (or make symbolic link) from my directory to darktable’s directory. I would prefer a darktable configuration option to tell it to also search for ICC profiles in my own directory.

A workaround is:

cd %USERPROFILE%\AppData\Local\darktable\color
mklink /J out %ICCPROF%

… where ICCPROF points to the directory I keep ICC files in.

  1. I copied XYZ-D50-Identity-elle-V4.icc to darktable’s directory, and tried to export with that profile. darktable says “Unsupported output profile replaced by sRGB”. CMYK profiles such as v2 USWebUncoated.icc also fail. Why are these unsupported? Can they be supported?

A workaround is to post-process with ImageMagick, eg:

magick fromDT.tif -profile XYZ-D50-Identity-elle-V4.icc out.tif

Both darktable and ImageMagick handle values outside 0 to 100% with no apparent problem. But not everyone uses ImageMagick, and if darktable can use these profiles, that would be better.

2

You can ignore that. It doesn’t show that on Linux, but it’s mostly cosmetic.

Good question. Currently there is no way to tell dt-cli to skip loading an XMP file.

That needs to be updated then. Thanks for reporting.

Right, that is not configurable.

The CMYK can’t be supported as darktable can’t deal with four color channels. The XYZ profile might be possible, however, dt has an XYZ profile built in already. So I don’t really see a point in using another profile for that.

3

Thanks for the answers.

Okay, no problem. I can specify the “null” XMP file I gave above or, if the real sidecar exists, I can temporarily rename it.

4

I too am getting gtk_disable_setlocale() must be called before gtk_init() from darktable-cli and a messsage box regarding the backtrace and get no output image. Is there a way to fix this as I use the cli for automated conversion on Linux and it would be very handy if it could work on Windows.

5

A good first step would be to provide that backtrace.