Exporting Issues

That's right. The Windows-native apps have used two different models for not color managing.

One is to ignore it altogether, just pass the numbers straight through. In that case exporting to Adobe RGB would look roughly right on a wide gamut monitor.

The other is the old Internet Explorer mode: convert source profiles correctly - but into sRGB; not into the proper monitor profile. This would always oversaturate on a wide gamut monitor, whatever the source profile.

I don't ever use any of these apps, so I have no idea which mode each operates in.

And just in case anyone wants to test against Photoshop Export - don't. It's totally broken at the time and doesn't display correctly ("ignore" mode). The rumour is that they're totally rebuilding the whole Export module, so we'll have to wait and see.

Having done some testing, this is a bit more complicated than what I first wrote.

On my wide gamut monitor, the desktop will display Adobe RGB and ProPhoto files equally over saturated.

The Photos app will also display them over saturated, but less over saturated than the desktop and Photos.

Paint will display them both equally dark and desaturated, and with a purple cast.

The same thing happens in the third party image viewer FastStone with color management turned off.

I'm not sure, but think this different behavior between non-color managed applications may be caused by some of the applications being aware of the document profile (but not the monitor profile), and some applications not being aware of any profiles at all.

Hopefully, @D Fosse  can shed some light on this.

And exporting in Adobe RGB won't help, the image will still display over saturated on the desktop.

I am a Mac user, so I can't try it, but this would surprise me. If you export an image in AdobeRGB, then the RGB values of all the colors will be lower than when you export the same image in sRGB. That means the image should be less saturated, unless the viewer does support color management.

And exporting in Adobe RGB won't help, the image will still display over saturated on the desktop.

Yes this is typical behavior when using applications without color management on Windows with a wide gamut monitor.

Except the Edge browser, no native Windows applications are color managed.

This includes the File Explorer, Paint, Photos and the desktop.

I don't know if the background photo is displayed with color management in Windows, but I would not be surprised if that wasn't the case. If you have a wide gamut monitor in such a situation, you should export the image for the gamut of that monitor, so try exporting in AdobeRGB.

Are you calibrating your screen? To make profiles work correctly and to have the best chance of looking the same on color managed systems, you need to regularly calibrate the monitor.