Update embedded Preview in RAW-File between Darktable and Digikam

[pragomer]

Hi,

I asked myself the same questions as in this post:

How to synchronize metadata and file names between darktable and other photo/metadata editors?

12 years as a network manager and independent network consultant. I’ve seen my fair share of bad questions. Here’s the difference: As a network manager my duty is to the company. Therefore, it is my duty to keep asking “Why?” till I find out what they are really trying to do. I literally called it my “Rule of five Whys.” However, in a forum, it is none of those peoples’ business if I am asking the wrong question. It is not their job to make sure I am not wasting my time. And it is insulting for …

I find it also the best workflow (as darktable cannot handle filenames) to work fully in digikam for organisation, and then just editing in darktable.

The only remaining issue (when I compare it to lightroom from what I switched), that the thumbnail in digikam remains original, even when I edited it in darkable (to lets say monotone).

Is there any chance that digikam could show the preview of the (darktable) processed image? (like replacing the embedded preview)

If not, it is still ok for me, just wondered if such a thing would be possible.

Many thanks to this awesome community here.

Kind regards

Pragomer

[paperdigits (Mica)]

@pragomer

Is there any chance that digikam could show the preview of the (darktable) processed image? (like replacing the embedded preview

That is not possible, sorry.

[dani_l]

It is possible to replace the preview image embedded in raw files using exiftool like this:

exiftool "-previewimage<=preview.jpg" image.cr2

I tested this using a CR2 file and digikam will use this image to for the thumbnail and also the full size preview.

It is probably not too hard to automate that process (e.g. using Lua scripting in darktable). While this is possible, there are many reasons why I would strongly recommend against doing that:

• Raw file formats are not designed to be modified later (that is why all applications use sidecar files) and while it works, it is probably not tested too well and bugs might destroy your image. Also, raw file formats are usually undocumented and only understood through reverse engineering. Try to find and read discussions about whether or not it’s a good idea to convert all raw images to DNGs before making a decision…
• If you regularly do incremental backups, a duplicate of the whole raw file might be stored every time you modify the embedded preview.
• If i understood it correctly, there can only be one embedded preview and for my camera, that is a ~1.5 MB full resolution version of the OOC JPG. Since I don’t shoot RAW+JPG, that is the only way to check how the out of camera picture looks like. I wouldn’t want to lose that.

That said, I would love to see digikam having some integration with darktable. It should not be that hard for digikam to notice that the xmp contains a darktable history stack and then e.g. use dbus and some Lua scripting to obtain thumbnails and full resolution images as needed. Also, it would be awesome if digikam would understand darktable’s notion of duplicates (xmps with _01/_02/… in the filename; right now those files won’t be moved along with the images by digikam and it is impossible to edit their metadata).

Unfortunately, I have not seen anything in that direction yet or heard about someone working on it. The best workflow I know is having a separate folder with up-to-date exported images… I would be really interested if somebody has a better solution.

[LebedevRI (Roman Lebedev)]

@dani_l

might destroy your image.

Pretty much will, if you account for the number, and different raw formats, of files.
It’s really not a good idea. Perhaps XMP spec has some section about storing an override
for the thumbnail, or they didn’t think about it?