Darktable comparison inconsistency

Software darktable
1

What am I doing wrong? I try to use the comparison feature (culling layout) in Darktable and the results are all over the place.

Let me explain. The current sample is a raw+JPG duo of images. Fujifilm X-T3. JPEG is on the left, raw file (RAF) on the right.

dt1
dt12010×1484 759 KB

Both look identical. To be fair I don’t expect this to be the case as the JPEG is with some “film simulation”, but let’s take this as the predicate.

If I zoom to 33%, here is how it looks:

dt2
dt22010×1484 633 KB

it no longer look the same: the raw file is rendered differently that in the “fit” zoom. This shouldn’t be.

Then if I zoom to 100%

dt3
dt32010×1484 484 KB

Notice how all the detail is lost in the raw file and it look jagged, while the JPEG has it all.

The 100% view for the raw file in “darkroom” look like that:

dt4
dt42010×1484 560 KB

It look smaller, but has much more details.

What option do I need to toggle to have: 1. consistent rendering of the raw file across zoom level 2. that 100% view of the raw file be 100%. 3. that 100% in darkroom be like 100% in “culling layout”.

These are the options for thumbnail generation:

image
image1760×138 8.05 KB

2

The zoomed out view of the RAF is just the embedded preview, which looks identical to the JPEG. As soon as you zoom in (or edit) the RAF, you see Darktable’s rendering.

1 Like
3

To add to this.

If I change “use raw file instead of embedded JPEG from size” to “always”, the first view looks like this:

dt5
dt51792×1344 497 KB

As a note I do believe this should be the default behaviour: it should NEVER show the embedded previews in the file but rather the output of darktable processing.

This is more inline of what I was expecting, but then the 100% view is even worse:

dt6
dt61792×1344 201 KB

The JPEG is pixelated. The raw file hasn’t improved.

4

Yes that’s what I guessed, but it’s just wrong. It defeat the whole purpose of comparison if what you see is what you won’t get.

5

Change your thumbnail settings to always use the raw and adjust your thumbnail cache preferences accordingly.

1 Like
6

The raw won’t ‘improve’ unless you improve it (develop it). You may wish to pick a different demosaicing method, add sharpening etc.
As to why the quality of the JPG got worse: you may have found a bug. I think it’s worth reporting on GitHub.

7

but then see the followup. The JPEG became pixelated at 100%.

9

See the default rendering in the “darkroom” that I post. The culling view is not even close. It should be the same in both (for the raw file, again I’m not expecting it to match the in camera JPEG in colour / sharpness / contrast). It’s not a matter a chosing a different algorithm. It just doesn’t do the same thing.

10

100% is what Darktable UI displays. So you tell me.

The out of camera JPEG (left) is 6240x4160 and the raw (right) is 6240x4160.

(edit: post I replied to was deleted before I could post this reply)

11

Could you share the raw and xmp?

12

Your issue has been explained here so I will not address that anyfurther. However, I often have opened the jpg in darkroom view and take a snapshot. I then move on to the raw file and I can open the jpg snapshot to do a comparison of how my edit compares to the jpg. In DT 5.1 I can have my snapshot loaded as a side by side comparison but this feature is not in DT 5.0. Here is a screen shot of the JPG snapshot on the left and the RAW unedited on the right. Yes they look different because the RAW is unedited. It is up to me to do edits to get them to look similar if that is what I want. DT in your case is working as designed and desired to work.

image
image2554×1528 1.94 MB

13

Yes I don’t expect the JPEG+raw to look the same side by side[1], but it seems that for the look of the raw file to be consistent across zoom level one must set an option for thumbnails to a non default value.

[1] This would be more “please reverse engineer Fujifilm film simulation” kind of feature request, that’s not even the object here.

14

@hub would you be able to share the raw file here ?