When I took workshops with my teacher I was told to work with the Munsell color system and because of this have learned a great deal about color values. There are some colors though that give me a hard time and I always wished that there was a color picker of sorts that would allow you to point to a certain color on your monitor and have you get somewhat of an idea what value you are dealing with.
Keeping in mind that monitor resolutions are very different from what is observed in life, adjustments still have to be made. With that in mind I was still thrilled to find the M color Meter, which does offer some hints to the color values in an image and gives you the Munsell read out as well.
1. To "SEE" a color -- mColorMeter is a color picker that shows Munsell notation.
2. Show color values in multiple color models/encodings at the same time.
3. Color management supported -- see color values in just what color space/profile you want.
4. Handy hot keys -- use CMD+LineNo. to copy specified color value.
use Shift+CMD+C to copy color as image.
5. Management of interested colors
Open the "Favorite" colors management window by selecting "Window"->"Favorite" (or CMD+F).
Use Shift+CMD+F to add interested colors to "Favorite".
6. Ability to export "Favorite" colors to adobe color swatch file formats (.ase & .aco)