Alas, color theory.
The term you are looking for is "value". Forget about the computer world for a second. The thing is a color can have a value, which is INDEPENDENT from it's saturation, but it's somewhat dependent on HUE. if you were to say make a 100% coverage of PMS YELLOW on a separate piece of paper have 100% coverage of PMS BLUE, you will find the latter has a darker value even tho they have equal saturation. It's possible that a tint ( fractional saturation) of a hue can have the same value as 100% of some other hue. RANDOM example 6% PMS BLUE might have an equal value as 100% PMS yellow.
This is all for example sake.
For this reason it is VERY DIFFICULT to start from a value ( some shade of gray) and derive a hue.
As long as we are on the subject, values GREATLY affect contrast. having colors which have all the same value will make for a very muted or dull design.