Darktable / RGBA / Alpha Channel

Good morning anyone,

I would like to use Darktable to post-process my 3D render from Blender (.png or .exr).
I have one problem with Darktable, and I think it’s normal. All my renderings have a transparent background (Alpha channel), and when I export to PNG from Darktable, I lose transparency.

From what I found, Darktable does not support the Alpha channel. Can you confirm this?

Thank you and best regards,


Wouldn’t krita be a better fit here?

I used Krita and Gimp as well, but I want to use my 3D render as a picture with Darktable to modify color, use LUT, etc…


I would agree that it would be nice to be able to use DT for this (which I do all the time) and retain a proper(ly modified) alpha.

On the the latter: unfortunately it is not enough to preserve and copy the alpha back , e.g. using ImageMagick. Certain operations, like bloom, should alter the alpha.

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On that note: the old DT Redmine tracker had an issue for this:
Feature #11186: Process and convey alpha channel

Here is the archived thread from the list on this.

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