This tutorial is for creating BLACK hair without a black using only 2 pens! Remember all my promarker & copics tutorials are shoestring ones. There are plenty of other tutorials available for using more colours such as on passion for promarkers blog so my tutorials are designed for people with limited colours or thse thinking of trying them out and wanting to only get a few colours to start off with.
Colour parts of your hair in the cool grey 1 leaving a band of white where the light will reflect (usually a bump on the hair)
Take your cool grey 1 and touch the nib onto the cool grey 5 as shown, it wont damage it! This will give you a cool grey 3 ish. If you're using copics scribble a bit off onto scrap paper first as the concentration will be too strong.
After picking up some of the colour from the cool grey 5 onto your cool grey 1 blend this over the cool grey 1 leaving a bit showing and not going into the white. Repeat this step as necessary to build up some tone.
Use your cool grey 1 and start to push the darker grey into your blended area and into the white, leave parts of this showing as required. You'll see how the cool grey 1 dilutes the 5 in the pic below creating more tone.