One thing I hear again & again is how confusing the M.A.C shade system is, with the NC’s & NW’s and the inbetweens.
I think the main source of this confusion is that in M.A.C terms, yellow skin tone is referred to as cool and pink referred to as warm. The opposite to what you would think, right?
Well, that’s because M.A.C use the artists colour wheel to determine between warm & cool shades, such as the basic one above. You can see above that yellow is actually a neutral colour but as the most common skintones are either yellow (or yellow/olive), pink (reddish) or a mixture of both, and only the darkest of skin tones usually having a blue undertone, it makes sense to call yellow cool, pink (red) warm and all the inbetweens neutral etc!
In the range there is also C##, C# & N colours.
*C##. (2 numbers following the C) is Olive/yellow....
(You can see from the wheel above why this is cool as the olive colour sits to the left of yellow, the cool side!)
*NC. is yellow but less on the olive side (Less any greenish hue)
*C#. (1 number following the C) is still yellowish but with a hint of pink.
*N. is opposite to C#, it is primarily pink but with a hint of yellow.
*NW. is regarded as the pink shade, with minimal yellow in it.
*W. the pinkest shade with no yellow present. (Pro only)
I read before that some people get their heads around it by referring to the NC as Not Cool & the NW as Not Warm. Not a bad way of dealing with it!
I hope this helps to de-mystify the colouring system a little anyhow ^_^