KDE Color Profiles
I switched to Kubuntu on a Dell XPS 15 a few months ago, and it's been a challenge to get color management working properly. After some trial and error and reading, I've managed to get it working using the steps below.
Enable KDE color profiles in System Settings -> Display and Monitor -> Compositor by checking the "Enable color correction" box and clicking "Apply."
Install ArgyllCMS and colord. On Kubuntu, you can do this by running
sudo apt install argyll colord.
When I installed Kubuntu, I first copied the color profiles from the Windows installation. Unfortunately, those profiles didn't work in KDE. When setting the profile with
dispwin, it showed a "Warning - No vcgt tag found in profile" message, and there were no noticeable changes to the colors. I found a color profile for this laptop on notebookcheck.net for now, but I'll eventually use a display calibration device to create a custom profile.
Install the color profile using the
dispwin <path-to-your-profile>. If it works, you should notice the colors on your display change when the command finishes.
My color profile wasn't applied automatically after restarting. To fix it, check
~/.config/color/icc/devices/display/*.icmand make sure it has the correct color profile file copied there. Also check
~/.config/color.jcnfand make sure the
ICC_PROFILEproperty contains the path to the correct color profile file.
If you run into problems or just want to better understand color profiles, I recommend reading the Arch Linux ICC Profiles wiki page and the Wikipedia Linux Color Management page.