Hey
These will explain a lot:
http://www.ludd.ltu.se/~torger/dcamprof.html
Basically: you need to profile your monitor, which usually involves calibration. The calibration curves are stored in the same ICC file which contains the profiling information, for convenience. These calibration curves are loaded into the video card (GPU) which changes colors of everything on the screen. That gets you just half way there, and if you stop there you’re nowhere near seeing correct colors. The next half is using a color-aware application (image viewer, photo editor, web browser) which will use the profile information from the ICC file to adjust colors of whatever its showing so that they look correct on your monitor with your calibration curves loaded into the GPU. The way it will “use the profile” involves the rendering intent, and neither of my two favorite Linux image viewers - Geeqie and Gwenview - support letting the user choose the rendering intent. Which sucks. Big time. Because now I have to make a new monitor profile with the appropriate rendering intent baked-in. But I digress. Only when your software does the above can you feel secure that your colors are accurate.
By the way, the most commonly used intent for day-to-day viewing is “relative colorimetric”.
About automation: The X window system supports a variable, an “atom”, called _ICC_PROFILE which is the standard place where the “correct” monitor profile for the current screen should be referenced. I believe dispcalGUI sets it when you “install” a monitor profile. Applications can then check for this atom and if it contains something, they can load it for you. Otherwise you must pick the right monitor profile manually.
A general problem is that most developers aren’t photographers and they may have a vague notion of color management and be motivated to implement it in their software, but as they don’t actually use it the end result is a half-baked sham of a feature, and that way you end up with programs which for example don’t let you select a custom monitor profile if the X atom is set, or don’t let you select the rendering intent. There is no such thing as “partial color management support”. It either works end to end and allows you to set all the things which need to be set and which are up to the user and not up to the developer to decide, or it does not.
In your screenshot I see Firefox and Chrome. I haven’t looked at Firefox in a while so I won’t comment, but Chrome does not support color management. If you load calibration curves into the GPU then the images inside Chrome and everything including the Chrome window decorations and the mouse cursor itself will be affected, but the color’s won’t be correct because it won’t use the profiling part of the ICC file. Out of luck.
Nope, that’s just the calibration curves being loaded into the GPU.
That’s called soft-proofing and it requires that you use a calibrated and profiled monitor with loaded calibration curves and applied ICC profile.