Newbie Question: Why Does Exporting As PNG Darken The Colors?

Hello. :slightly_smiling_face:

I apologize if this has been answered before but I did a bit of a search for the answer and I couldn’t find it.

I was doing some tutorials to learn GIMP but ran into an issue when I try to export a project as PNG. The colors come out darker than they should be like so:

Original color:

PNG export color:

If I export it as a JPG the colors come out as they should. The only way to avoid the issue as a PNG export is to uncheck “Save color profile” in the Export menu.

Obviously it’s something with the color profile but I don’t know what it is and what setting I need to adjust in order to avoid this other than unchecking that “Save color profile” option.

Thanks in advance.

For the longest time, PNGs have had profile compatibility issues. Things may have progressed albeit slowly. Which brings me to this question: which colour managed and PNG profile compatible apps have you checked? Do they all consistently show this colour?

I’m not sure what you mean but this is the first time I’ve worked with a photo editing app. Like I said, I’m a newbie and ran into this issue while learning GIMP. :slightly_smiling_face:

Good morning, @DRM,

I tried to repeat your problem, but here, everything looks normal!?!

Screenshot_20200315_083405

Please be more specific:
Operating system?
Gimp version?
Monitor?
What tutorial where you following? Where does it go astray?

Have fun!
Claes in Lund, Sweden

Good morning, Claes.

  • Windows 10
  • Gimp version 2.10.18
  • I’m not sure why the monitor would matter. Can you see the difference between the original color and the PNG export color I posted?
  • I was following the Liquid Dispersion tutorial by Logos By Nick:

This was the first time that I noticed this issue when I tried to export the tutorial project. Since then, this issue has happened again like when I recently brought in a png snapshot I was sent of something then I tried to rotate the image and crop it in GIMP. When I tried to export it the issue happened again.

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How are you viewing the exported photo? With Gimp or an image viewer?

I’m not sure why the monitor would matter

Because certain monitors are not especially uniform when presenting colours. An icon at the top of the monitor looks quite different from a copy of it, placed at the bottom. As well as when viewed from different angles.

I just performed the same test as I did above, now on Win 10
and the version of the Gimp that I have there, i.e. 2.10.14
capture

Yes, I clearly see the difference between the two patches that you posted.

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Makes sense. We are all here to learn. :sunny: Let me break down the 2 things that I mentioned briefly:

1 Tagging. Not all apps are compatible with the more obscure PNG tags, particularly the colour profile. This has been an ongoing issue for 2 decades because they are much less popular than JPGs, so devs don’t see it as a priority to add the compatibility, or aren’t even aware of the issue. I think GIMP at this point in time can read and write PNGs properly. Please verify.

2 Colour management. This is a complex topic that you could read more about in other threads. I explained it too many times to want to do it again. :stuck_out_tongue: Essentially, the camera, monitor, your eyes, etc., etc., see or want to see or show the data differently. Colour management allows us to be on the same wavelength, to make it an idiom.

Hope this helps!

Good question. :slightly_smiling_face: I’m on Windows but I switched to Nomacs recently as my default image viewer and as such I was just looking at the image on Nomacs and Gimp.

On Gimp the picture looks fine.
I’m on Windows, so on Microsoft Photos the image also looks fine.
But on Nomacs and Microsoft Paint the image comes out with the darker colors like I’ve shown.

So what does this mean if on some apps show the png fine and on some others it doesn’t?

I think Nomacs and the Windows 10 photos app don’t do proper color management. It means they are probably not displaying the colors correctly.

So does that mean that there is nothing wrong with the png as I exported from Gimp and it’s just an issue with Nomacs? Because this isn’t an issue with all png in Nomacs.

@afre and @Claes, any thoughts? Are there settings in Nomacs I need to make?

@DRM Sorry, no idea. Sounds as if their colour management is totally off:

Thanks for the link. Is there an alternative FOSS image viewer to use other than Nomacs? I’m planning on moving on the Linux one day and was easing my way in by trying to find FOSS programs to use on Windows. If Nomacs is having color management issues then what should I use to view photos instead?

Sorry, @drm, no good advice from me re Windows.
I am 100% Linux (Manjaro/KDE).

What do you use on Linux as your image viewer?

Mostly darktable :slight_smile: if not, then gwenview.

Okay. So I just installed Darktable. I threw the png in there and it shows it just as dark as it does in Nomacs. :neutral_face:

@DRM Still on Windows? You have to colour manage the entire chain!

I don’t know what that means. :grimacing:

Search the forum.
Computer + graphics card + monitor -> a certain profile.
It has to be loaded into your operating system (automatically).
The software you use has to know of and to be able to use this profile as well. Like firefox, darktable, … … …