About a month ago, whenever I try to blend dark colors they end up looking posterized and distorted. I've tried uninstalling and reinstalling different versions of krita but the problem still persists. (I'm currently using krita 4.1.5) I didn't have this problem before and I tried using krita on another laptop and there's no problem there either. I'm getting desperate since I can't find any solutions to it online either. Here's a bunch of examples:

Uninstalling and reinstalling Krita won't help. First try to reset the settings: https://docs.krita.org/en/KritaFAQ.html ... figuration . If that doesn't help, you need to provide more information so we can figure out what you're doing, like which blending mode you're using, opacity and flow settings, which colorspace you're using -- the images you provide aren't telling me what you think is wrong.

If you produce a 'posterised/distorted' image and Save it, then transfer that .kra file to the other 'good' laptop (which you say doesn't have this problem) then does the image display with or without the posterisation when opened in krita?
If you produce a 'posterised/distorted' image and Export it as a .png, how does it look when viewed on the 'good' laptop?

If you create 'good' images on the 'good' laptop and transfer the .kra file and a .png file over to the 'bad' laptop, what is the result?

I'm trying to draw a distinction between the creation of an image and the display of an image, which may (or may not) give useful diagnostic information.