Project

General

Profile

Bug #11035

Differences between exported images and edited images

Added by Guilhem Ribart about 4 years ago. Updated over 3 years ago.

Status:
Fixed
Priority:
Low
Assignee:
-
Category:
General
Target version:
Start date:
05/21/2016
Due date:
% Done:

100%

Estimated time:
Affected Version:
2.0.4
System:
Ubuntu
bitness:
64-bit
hardware architecture:
amd64/x86

Description

Hi

Since at least 2 years I face big differences between some specific edited images in Darktable and the exported one as you can see in the attached files.

I think it happens when I want big contrasts between the shadows and brigth areas in the image, whatever the image is in B&W or colored.

Capture du 2016-05-21 21-42-45.png (67.1 KB) Capture du 2016-05-21 21-42-45.png Guilhem Ribart , 05/21/2016 10:49 PM
Capture du 2016-05-21 21-45-33.png (37.7 KB) Capture du 2016-05-21 21-45-33.png Guilhem Ribart , 05/21/2016 10:49 PM
Capture du 2016-05-21 21-43-07.resized.jpg (363 KB) Capture du 2016-05-21 21-43-07.resized.jpg Guilhem Ribart , 05/21/2016 11:26 PM
_R000091.DNG.xmp (4.76 KB) _R000091.DNG.xmp Guilhem Ribart , 05/27/2016 07:15 PM

History

#1 Updated by Guilhem Ribart about 4 years ago

Here is the screenshot to show the difference between the edited image and the exported one.

#2 Updated by Guilhem Ribart about 4 years ago

I'm sorry but I've got issue to upload the sreenshot and I don't know how to delete wrong posts :(

#3 Updated by Guilhem Ribart about 4 years ago

Here's the last attached file (if it works....)

On the left is the view of the picture edited with Darktable and on the right is the exported image. As you can see it's really different :(

Here are the presets I use:

And finally the export settings:

#4 Updated by Ulrich Pegelow about 4 years ago

  • % Done changed from 0 to 20
  • Status changed from New to Incomplete

This is likely a color management topic and you can only judge on those if all the tools are color managed in a proper way. First thing: is the image viewer in which you display the jpeg using colormanagement? If you are not 100% sure, forget the output. In question you should use Gimp for jpeg display which supports color management (of course it needs to be set up correctly with your screen profile Edit->Preferences->Color Management->Monitor Profile).

To check if darktable can find the same screen profile run darktable-cmstest ([[http://www.darktable.org/usermanual/ch01.html.php#darktable_cmstest_commandline_parameters]].

#5 Updated by Tobias Ellinghaus about 4 years ago

Ulrich Pegelow wrote:

In question you should use Gimp for jpeg display which supports color management (of course it needs to be set up correctly with your screen profile Edit->Preferences->Color Management->Monitor Profile).

Or just import the JPEG into darktable. Even when color management is broken there it should be the same for raw and JPEG so they are comparable.

#6 Updated by Guilhem Ribart about 4 years ago

Ulrich Pegelow wrote:

This is likely a color management topic and you can only judge on those if all the tools are color managed in a proper way. First thing: is the image viewer in which you display the jpeg using colormanagement? If you are not 100% sure, forget the output. In question you should use Gimp for jpeg display which supports color management (of course it needs to be set up correctly with your screen profile Edit->Preferences->Color Management->Monitor Profile).

To check if darktable can find the same screen profile run darktable-cmstest ([[http://www.darktable.org/usermanual/ch01.html.php#darktable_cmstest_commandline_parameters]].

Thank you for your reply.

When I run the command:

darktable-cmstest version 2.0.4
this executable was built with colord support enabled
darktable itself was built with colord support enabled

eDP1    the X atom and colord returned the same profile
    X atom:    _ICC_PROFILE (1429052 bytes)
        description: LSN133KL018 #1 2016-05-16 11-26 2.2 F-S XYZLUT+MTX
    colord:    "/home/------/.local/share/icc/LSN133KL018 #1 2016-05-16 11-26 2.2 F-S XYZLUT+MTX.icc" 
        description: LSN133KL018 #1 2016-05-16 11-26 2.2 F-S XYZLUT+MTX

Your system seems to be correctly configured

I got the same problem when I ise GIMP, Gthumb or any other software.

My screen is calibrated every month.

#7 Updated by Guilhem Ribart about 4 years ago

Tobias Ellinghaus wrote:

Ulrich Pegelow wrote:

In question you should use Gimp for jpeg display which supports color management (of course it needs to be set up correctly with your screen profile Edit->Preferences->Color Management->Monitor Profile).

Or just import the JPEG into darktable. Even when color management is broken there it should be the same for raw and JPEG so they are comparable.

When I import the JPG file into Darktable, it's definetely not the same between JPEG and RAW :-(

#8 Updated by Ulrich Pegelow about 4 years ago

When I import the JPG file into Darktable, it's definetely not the same between JPEG and RAW :-(

Well, then your color management seems not to be the culprit. Could be an out-of-gamut situation then. I assume you are working on a wide-gamut monitor so darktable can display colors up to AdobeRGB or the like. When exporting to jpeg darktable needs to limit the colors to the much narrower sRGB color space which will always lead to a loss of color information for colors outside of sRGB. You may activate output via LittleCMS2 in the core options which will give you some additional options on rendering intent, i.e. the way how out-of-gamut colors are dealt with.

In addition you might be plagued by unbound colors ([[http://www.darktable.org/usermanual/ch03s02s10.html.php]]) - a situation that occurs quite frequently with blue LED lighting. There is a "gamut clipping" option in the "input color profile" module that helps you deal with these situations. More is explained in the user manual.

You may also upload your raw + xmp files here so we can have a closer look.

#9 Updated by Christian Kanzian about 4 years ago

Just for understanding, because I often switch softproof set to sRGB on/off and notice the some parts of an image get a bit darker like the sample here.

Will softproof to sRGB within darktable help to better deal with colors in such situations and show them same colors as the export on wide-gamut monitors?
I don't have a wide-gamut monitor to test this.

#10 Updated by Guilhem Ribart about 4 years ago

Thank you very much Ulrich for trying to help!
My monitor is not a wide gamut monitor. I use a Dell XPS15 (2015 version). It covers something like 95% of the sRGB color space only :(

I tried to use LittleCMS2 but it doesn't change anything :(
K tried to use the "gamut clipping" option and it's better but still not what I need.

I uploaded the DNG and xmp files into Mega. Please download the files and tell if you face the same issue.

Thank you

https://mega.nz/#!7o0xCSrS!GAK7S0Gqh3xDi9eSnoA6OxQOBJyNhPPHM7VyamPwem0
https://mega.nz/#!6o8wBZBC!WRgYEnfrnKiSJRFQs_1TptRTE_9ccRbpPcSSKMFu3Lg

Ulrich Pegelow wrote:

When I import the JPG file into Darktable, it's definetely not the same between JPEG and RAW :-(

Well, then your color management seems not to be the culprit. Could be an out-of-gamut situation then. I assume you are working on a wide-gamut monitor so darktable can display colors up to AdobeRGB or the like. When exporting to jpeg darktable needs to limit the colors to the much narrower sRGB color space which will always lead to a loss of color information for colors outside of sRGB. You may activate output via LittleCMS2 in the core options which will give you some additional options on rendering intent, i.e. the way how out-of-gamut colors are dealt with.

In addition you might be plagued by unbound colors ([[http://www.darktable.org/usermanual/ch03s02s10.html.php]]) - a situation that occurs quite frequently with blue LED lighting. There is a "gamut clipping" option in the "input color profile" module that helps you deal with these situations. More is explained in the user manual.

You may also upload your raw + xmp files here so we can have a closer look.

#11 Updated by Ulrich Pegelow about 4 years ago

I uploaded the DNG and xmp files into Mega. Please download the files and tell if you face the same issue.

Sorry, but your cloud upload doesn't work for me.

#12 Updated by Guilhem Ribart about 4 years ago

Ulrich Pegelow wrote:

I uploaded the DNG and xmp files into Mega. Please download the files and tell if you face the same issue.

Sorry, but your cloud upload doesn't work for me.

:-(

I suggest to upload the files on wetransfer and to add the email of your profil. Are you ok with that?

#13 Updated by Guilhem Ribart about 4 years ago

:-(

I try with wetransfer. You should have received an email to download the files.

Otherwyse here is the link: https://we.tl/ySBNRJTpW2

#14 Updated by Ulrich Pegelow about 4 years ago

OK, got the files and checked it.

What happens here is a massive out-of-gamut situation which you generate by extreme settings in the colorcontrast module. You increase the contrast in the b-channel (yellow/blue) by a factor of 3.5 which is massive. As a consequence you get areas with b-values up to almost -300. This is way beyond the sRGB gamut (up to maybe -100 according to wikipedia). So in a way you are shooting yourself in the foot with that setting :)

When darktable exports the image to JPEG it limits the colors to the sRGB gamut and hence the differences between what you see in the darkroom (in color monitor gamut) and the exported sRGB file.

On my wide gamut monitor I get a quite good preview of the exported JPEG when activating softproof with sRGB as softproof gamut.

#15 Updated by Guilhem Ribart about 4 years ago

You're my hero! :)

Sorry for my late reply, I was very busy since 3 days :(

I understand what you explain and it goes in a way I was thinking about. I tried to export the edited picture in TIFF 16 bits and I get also a good preview. Now I understand why there is a difference between the picture in Darktable and the exported on in JPEG sRGB.

Thank you very much for your help!!!

#16 Updated by Ulrich Pegelow about 4 years ago

  • % Done changed from 20 to 100
  • Status changed from Incomplete to Fixed

You're welcome :)

#17 Updated by Roman Lebedev over 3 years ago

  • Target version set to 2.2.0

Also available in: Atom PDF

Go to top