Gimp exported image gets darker

[Akkou]

For example take this original image: https://i.imgur.com/ud3kX6Y.png
Compared to this: https://i.imgur.com/tTptnwm.png
I didn't edit it in any way or change any settings yet whenever I export it, it gets darker making it easier to see artifacts and overall making it unpleasant to look at.
GIMP version 2.10.22 Windows 10

[rich2005]

(05-19-2021, 02:17 AM)Akkou Wrote: I didn't edit it in any way or change any settings yet whenever I export it, it gets darker making it easier to see artifacts and overall making it unpleasant to look at.

Nothing done between original and exported ?

Apart from the sightly larger image size. 1607x683 -> 1611x685 There must have been something, there is a degree of combing in the exported image with associated colour loss. Down from 8113 to 4561. You can see in the color-cube analysis Colors -> Info -> Colorcube Analysis

   

I took your original, exported as a png from Gimp and analyzed with imagemagick.
Changes in your export, no changes in my export. Some change in blue and green.

   

Not able to reproduce your change.
Subjectively, viewing your before and after images in a linux image viewer, I see not difference, Using Windows ? Windows image viewer has been known to impose its own 'tweaks'.

If you do decide to do any editing, try bumping the precision up Image -> Precision 32 bit FP although with that type of dark image, some loss of colour is going to occur.

[Akkou]

(05-19-2021, 07:47 AM)rich2005 Wrote:

(05-19-2021, 02:17 AM)Akkou Wrote: I didn't edit it in any way or change any settings yet whenever I export it, it gets darker making it easier to see artifacts and overall making it unpleasant to look at.

Nothing done between original and exported ?

Apart from the sightly larger image size. 1607x683  -> 1611x685 There must have been something, there is a degree of combing in the exported image with associated colour loss. Down from 8113 to 4561. You can see in the color-cube analysis Colors -> Info -> Colorcube Analysis



I took your original, exported as a png from Gimp and analyzed with imagemagick.
Changes in your export, no changes in my export. Some change in blue and green.



Not able to reproduce your change.
Subjectively, viewing your before and after images in a linux image viewer, I see not difference, Using Windows ? Windows image viewer has been known to impose its own 'tweaks'.

If you do decide to do any editing, try bumping the precision up Image -> Precision 32 bit FP although with that type of dark image, some loss of colour is going to occur.

The change in image size is due to a horrible crop to showcase how it looks on my desktop. (the colors look almost identical in browser if I upload them instead of cropping them how I see them on my desktop.)
Are there any settings you suggest I change to get nearly identical colors to original file? I'm not great with technical things in gimp so I don't even know where to begin.
Changing precision from 8bits to 32 didn't help sadly. 
I just wanted to do a minor edit to the image to use as my background, but again without changing anything and just exporting it introduces more artifacts sadly.

[rich2005]

Maybe someone will come up with some advice. I can not see any real change other than that drop in colour count, so no useful advice.

If you could indicate what the artefacts are it might help. I superimposed one image on top of the other and can not see any difference.

[PixLab]

may be diminish the compression level when you export as there is a big difference in size between your 2 images (the original image is ~190 Kb, the darker image is ~150 Kb)

Other than that, the only thing which comes to my mind right now is the color profile, you might have some clipped colors at export
did you tried to save the color profile while exporting?
   

[Aries97]

(05-19-2021, 02:17 AM)Akkou Wrote: For example take this original image: https://i.imgur.com/ud3kX6Y.png
Compared to this: https://i.imgur.com/tTptnwm.png
I didn't edit it in any way or change any settings yet whenever I export it, it gets darker making it easier to see artifacts and overall making it unpleasant to look at.
GIMP version 2.10.22 Windows 10

I was having this problem on Ubuntu 20.04, the "image viewer" application was just displaying the image too darkly.  Opening the same image with Shotwell showed the image exactly as I expected it to be.

[jefferyrowley@netscape.net]

I have had this issue for the past three years, but I have found an answer. You can save GIMP images however you wish to save them. During the Export process from GIMP to a *.png Make sure that you have "Save background color" AND "Save color profile" un-ticked during the export process. I used to audit a software program for twenty years and so three years ago I began the long and arduous process of finding the correct combination of ticks at the GIMP "Export Image and PNG". I used every combination available. This has seriously hampered my graphic work for several years because I had to rely on 3rd party or (horror of horrors) use the default Windows 10 Image reader to change the color, temp and contrasts. It never came out correct. I make touchscreen graphics for a complex musical instrument and the graphics have to appear realistic in every way. GIMP does a splendid job of producing and rendering the original materials and graphics. I have had three projects (which take about 1.5 years to complete correctly) on hold because I could not fix this issue and the forum has been zero help.
col
All one has to do is to make sure that these two boxes go un-ticked and uploading the images to be adjusted has to never happen. It must be the native GIMP Color profile AND the background color. All of my images have differing background colors depending upon how I wish to have the layers appear. Apparently Mr. PNG uses this information to produce an image on your screen. I did try un-ticking only one of the boxes, but the image did the same thing when viewing from any program. It was not until I un-ticked both boxes that I had success! In fact the image appears in the two programs that I export to exactly as my GIMP rendering.

[eenrsa]

(11-04-2023, 11:51 PM)jefferyrowley@netscape.net Wrote: I have had this issue for the past three years, but I have found an answer.    You can save GIMP images however you wish to save them.   During the Export process from GIMP to a *.png Make sure that you have "Save background color" AND "Save color profile" un-ticked during the export process.    I used to audit a software program for twenty years and so three years ago I began the long and arduous process of finding the correct combination of ticks at the GIMP "Export Image and PNG".   I used every combination available.   This has seriously hampered my graphic work for several years because I had to rely on 3rd party or (horror of horrors) use the default Windows 10 Image reader to change the color, temp and contrasts.  It never came out correct.   I make touchscreen graphics for a complex musical instrument and the graphics have to appear realistic in every way.    GIMP does a splendid job of producing and rendering the original materials and graphics.   I have had three projects (which take about 1.5 years to complete correctly) on hold because I could not fix this issue and the forum has been zero help.
col
All one has to do is to make sure that these two boxes go un-ticked and uploading the images to be adjusted has to never happen.   It must be the native GIMP Color profile AND the background color.   All of my images have differing background colors depending upon how I wish to have the layers appear.   Apparently Mr. PNG uses this information to produce an image on your screen.    I did try un-ticking only one of the boxes, but the image did the same thing when viewing from any program.   It was not until I un-ticked both boxes that I had success!   In fact the image appears in the two programs that I export to exactly as my GIMP rendering.

Thanks mate. I nearly pulled out all my hair trying to figure this one out and your solution worked 100%

[kuberpunk]

(11-04-2023, 11:51 PM)jefferyrowley@netscape.net Wrote: I have had this issue for the past three years, but I have found an answer.    You can save GIMP images however you wish to save them.   During the Export process from GIMP to a *.png Make sure that you have "Save background color" AND "Save color profile" un-ticked during the export process.    I used to audit a software program for twenty years and so three years ago I began the long and arduous process of finding the correct combination of ticks at the GIMP "Export Image and PNG".   I used every combination available.   This has seriously hampered my graphic work for several years because I had to rely on 3rd party or (horror of horrors) use the default Windows 10 Image reader to change the color, temp and contrasts.  It never came out correct.   I make touchscreen graphics for a complex musical instrument and the graphics have to appear realistic in every way.    GIMP does a splendid job of producing and rendering the original materials and graphics.   I have had three projects (which take about 1.5 years to complete correctly) on hold because I could not fix this issue and the forum has been zero help.
col
All one has to do is to make sure that these two boxes go un-ticked and uploading the images to be adjusted has to never happen.   It must be the native GIMP Color profile AND the background color.   All of my images have differing background colors depending upon how I wish to have the layers appear.   Apparently Mr. PNG uses this information to produce an image on your screen.    I did try un-ticking only one of the boxes, but the image did the same thing when viewing from any program.   It was not until I un-ticked both boxes that I had success!   In fact the image appears in the two programs that I export to exactly as my GIMP rendering.

Thank you very much. You saved me!