Bug #10920

Darker export

Added by François Tissandier over 4 years ago. Updated over 4 years ago.

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I'm not sure what I'm missing, so I'm opening a ticket here.

My jpg are significantly darker than what I see in darktable. I tried on two different computers, with Darktable 2.0.1

Highlights seem to be the same, but dark areas are darker. I tried this to avoid as much editing as possible: I opened a photo, check the history and clicked on "0 original". Then I checked a dark area with the color picker. I exported in jpeg. Output color profile is sRGB. Then i opened the jpeg in gimp and used a color picker to check the exact same area. The difference is quite obvious, even without the color picker anyway. A dark zone with an average of 7/7/7 in Darktable is having an average of 1/1/1 in my jpeg file.

I really don't know why it's like that, on two different computers. I have tried to look at a lot of settings, but I don't understand this difference, it's really annoying since what i'm doing with my photos isn't what I'm seeing in the jpeg.

Entry color profile is "standard matrix", with no gamut troncature (any setting for this parameter doesn't change anything on the display nor export anyway).

I'm including a RAW and its jpg output. I made my test with the rooftop at the bottom right corner, the nearest full one. Average color picker on it gives me 7/7/8. On the JPG, the difference is obvious. (31 MB) François Tissandier, 02/18/2016 10:35 AM

Related issues

Is duplicate of darktable - Bug #9194: Color picker depends on display profileTriaged01/22/2013


#1 Updated by Roman Lebedev over 4 years ago

I'll bet it is related to display color profile
Please show output of darktable-cmstest
Also, which version of gimp are you using?

#2 Updated by Roman Lebedev over 4 years ago

  • Is duplicate of Bug #9194: Color picker depends on display profile added

#4 Updated by François Tissandier over 4 years ago

Thanks for your answer Roman

It's interesting, because I already had some color problems and I have reinstalled fully one of the two computers to make sure I was not using an old color profile. So what I saw today and shared with you is on a computer with a very fresh Ubuntu-Gnome, without any color profile installed. I had one for this screen and computer, but I can't even put it in the color manager of gnome, as the screen is not in the list of devices.

darktable-cmstest gives me this :

HDMI1 the X atom and colord returned different profiles
X atom: _ICC_PROFILE (0 bytes)
description: (none)
colord: "/home/tissanfr/.local/share/icc/edid-bed95af8e09cabeb5ae4eb8d5275f34d.icc"
description: DELL SP2309W

Better check your system setup
- some monitors reported different profiles
You may experience inconsistent color rendition between color managed applications

It seems that it's using the color profile provided by the EDID of the screen. The profile I have created with a Spyder for the previous OS isn't used. I have started to read the links that you shared, it's a bit technical for me, I need to really read carefully and try to understand.

What is weird is that if it's a color profile problem and GIMP is NOT using the color profile to display the JPG, but Eye of Gnome is, I should see the same image in Eye Of Gnome and Darktable. But even in Eye of Gnome, I see it darker. It's really annoying that on a very "standard" installation I have those differences. I need to check with my other laptop, but I had the same problem with this photo, and it's different hardware (but Intel graphic cards). Maybe it's a Gnome problem. And do you have any idea how I could fix it ? I wanted to use the color profile I had created for this screen, but Gnome doesn't even propose to use it for the screen, so I'm really confused.

Gimp is 2.8.14.

#5 Updated by Tobias Ellinghaus over 4 years ago

GIMP isn't using the colord profile, and my bet is that EoG isn't either. You might try setting the display profile in darktable to sRGB (right click the buttons in the bottom to set that). Note that the color pickers also work in the color space the pipe is using, i.e., the display space. So that might influence it, too.

#6 Updated by François Tissandier over 4 years ago

Good idea Tobias, indeed it's working ! I can select sRGB and it seems to be faithful.

Now i need to understand what my Gnome is doing, something is clearly not working well here. But at least I have a solution to use Darktable. Thanks a lot !

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