Weird artefacts when editing in ProPhoto RGB

D.Fosse is right about looking to disable the GPU as a first step

if that doesn’t help try this:

Windows display profile, display profile issues on Windows

At least once a week on this forum we read about this, or very similar issues of appearance differing between colour managed applications.

Of course you must not expect accurate colour with programs such as Windows "Photos", because colour management is not implemented there so such programs are incapable of providing accurate image display.

Unfortunately, with Microsoft hardware: Windows updates, Graphics Card updates and Display manufacturers have a frustratingly growing reputation for installing useless (corrupted) monitor display profiles.

I CAN happen with Macs but with far less likelihood, it seems.

The issue can affect different applications in different ways, some not at all, some very badly.

The poor monitor display profile issue is hidden by some applications, specifically those that do not use colour management, such as Microsoft Windows "Photos".

Photoshop is correct, it’s the industry standard for viewing images, in my experience it's revealing an issue with the Monitor Display profile rather that causing it. Whatever you do, don't ignore it. As the issue isn’t caused by Photoshop, don’t change your Photoshop ‘color settings’ to try fix it. 

To find out if the monitor display profile is the issue, I recommend you to try setting the monitor profile for your own monitor display under “Device” in your Windows ‘color management’ control panel to sRGB temporarily. 

You can ADD sRGB if its not already listed. 

And be sure to check “Use my settings for this device”.

(OR, if you have a wide gamut monitor display (check the spec online) it’s better to try Adobe RGB here instead).

Quit and relaunch Photoshop after the control panel change, to ensure the new settings are applied.

Screenshot of Color Management Control Panel 

Depending on the characteristics of your monitor display and your requirements, using sRGB or Adobe RGB here may be good enough - but custom calibration is a superior approach.

If this change fixes the issue, it is recommended that you should now calibrate and profile the monitor properly using a calibration sensor like i1display pro, which will create and install it's own custom monitor profile. The software should install it’s profile correctly so there should be no need to manually set the control panel once you are doing this right. 

Still got problems?

If you want to try a method that’s proved successful to rule out many an issue we see with Photoshop, you can reset preferences:

To reset the preferences in Photoshop: 

https://helpx.adobe.com/photoshop/using/preferences.html

Note: Make sure that you back up all your custom presets, brushes & actions before restoring Photoshop's preferences. Migrate presets, actions, and settings

I hope this helps

neil barstow, colourmanagement net :: adobe forum volunteer

google me "neil barstow colourmanagement" for lots of free articles on colour management

[please only use the blue reply button at the top of the page, this maintains the original thread title and chronological order of posts]

That sounds like a bad monitor profile (not at my workstation right now to examine the example closely).

ProPhoto is an extremely large color space, and that comes at a price: all errors in the color management chain get amplified. It's quite common to see problems in ProPhoto but not e.g. Adobe RGB.

With a wide gamut display you must have a calibrator. You just need to buy one. You cannot rely on manufacturer profiles, they are very often defective in various ways.