I've always had the need of a good colour picker and colour management app. There are lots of similar apps, but none of them (except Gcolor2/3, which is fantastic) fulfils my needs, so I ended up making my own as a mock-up. Hope you like it.
This mock-up follows GNOME Human Interface Guidelines. I wish I had time to learn and program it by myself.
15.10.18 - Updated the widgets to the new GNOME HIG (3.18).
14.09.29 - After reading the guidelines with respect to visual alignment spacing, some elements have been moved a little bit (the Picker tab mainly).
14.09.29 - Updated all the style to the current GNOME HIG. Also, for the sake of being it a wireframe (i.e., conceptual art) all the colours are gone.
13.09.02 - First release.