Colors change on export to JPG

Akhenaaten · **Joined:** Sep 29, 2016 **Posts:** 5

GIMP Version: 2.8.18
Operating System: Mac OS
OS Version: 10.11.6
GIMP Experience: New User

Hello,

I did some simple alterations (straighten and autocrop) to an image from a 35mm scan saved in JPG with a sRGB IEC61966-2.1 color profile. When I export the altered image to JPG, the color is not the same anymore. The dark greenish tones become more like red or brown. Given that I use mac (OS 10.11.6), I have tried to do the following: preferences>color management>mode of operation>no color management, and everything else set to "none", but it doesn't help. The file open behavior is set to "ask what to do", but it doesn't ask anything upon opening the original image. Does anyone know why it happens and how to preserve the original colors when exporting to the same format?

ofnuts · **Joined:** Oct 25, 2010 **Posts:** 4812

On the two images: Filters>Blur>Pixelize and give the size of the image, to get the average color of the image. You get #6F7678 on one #6F7778 on the other. So you have one unit of additional green, but that could be a round off error when exporting in JPEG.

Akhenaaten · **Joined:** Sep 29, 2016 **Posts:** 5

Any idea about how I could keep the original colors?

molly · **Joined:** Apr 07, 2010 **Posts:** 14182

Did you try exporting as png?

Akhenaaten · **Joined:** Sep 29, 2016 **Posts:** 5

Yes. The same.

ofnuts · **Joined:** Oct 25, 2010 **Posts:** 4812

Re-tried, cropped sky and sea and measured their average color separately, and still can't see any significant difference between the two pictures. These images do not seem to have a color profile.

Can you display the two images side by side on your screen (possibly zoomed to the area of interest) and make a screenshot?

sallyanne · **Posted:** Sat Oct 01, 2016 9:48 am **(#7)**

They look the same to me.

Akhenaaten · **Joined:** Sep 29, 2016 **Posts:** 5

The color difference is slight, but it is there.. Here are the screenshots.

ofnuts · **Joined:** Oct 25, 2010 **Posts:** 4812

1) there is a color profile in the images you sent
2) the average color of one is 111,118,120 and other is 110,117,119 (ie, very slightly darker, but sill the same light blue/green cast)

But the real proof picture would be: display the two images side by side on your screen, zoomed to the same area where you find the colors to be different. Then take a screenshot of the whole screen.

Akhenaaten · **Joined:** Sep 29, 2016 **Posts:** 5

Have tried to zoom in both pictures side by side, but I could not pinpoint the location where the difference would be the most visible. Looking at the whole picture, the cloud and horizon line in the centre is where I think it's the easiest to spot the difference, but this slight brownish/reddish film covers it all. As you have also pointed out, the color isn't the same, but there's aboslutely nothing I can do about it as I wasn't able to find any solution to this problem. Thanks for checking them out anyway.