Grey blue combination

Do you believe for every grey tone there is corresponding blue such that there is a “perfect” match-id we can say that of course
I know that is good to use colors with similar saturation but in the above case, by definition, gray has no saturation at all and blue is saturated more or less.

My motivation for this question is that hotmail) has a light grey sidebar(left) and a blue top bar where the controls are depicted upon
selecting message.

It is a good combination and I wanted to know what are the “mechanics” behind it cause I am building a site where there will be light grey and blue top bar and
I want to find some good color combo to implement also.


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.

Ok…for coclusion,can you make a comment as to why the grey-blue combination in Outlook looks so appealing.
Is it the value difference after all?