Mixing a neutral

I've mixed and tubed Munsell neutrals N4, N6 and N8. No matter which neutral I am mixing, the process and paints are the same. Here's a look at the process.

Material and tools. 
Williamsburg Ivory Black, Rublev Cyprus Umber Medium and hand-mulled titanium dioxide. Munsell Neutral Value Scale Glossy, palette knives and glass palette.

Workspace layout.
All the paints are ready to mix. This is my mulling glass abraded with silicon carbide, although I use the smooth side for mixing. Abraded side is used for mulling only.

Testing mix accuracy.
It is best to test accuracy by applying paint directly; the glossy scale easily wipes clean. Note that at this time all we are matching for is N8 value; color matching comes later. Black is added to white bit by bit, constantly checking for spot on value.

Black/white mix completed.

Testing mix accuracy.
The umber and white is mixed to the same N8 value. Note that at this time all we are matching for is N8 value; color matching comes later. Reflection makes the paint sample look lighter here. Spreading the sample with a finger helps achieve an easier read.

Umber/white mix completed.
On the palette is now a pile of N8 leaning cool and a pile of N8 leaning warm.

True Munsell N8.
The two N8's are now mixed, testing all the time for value and hue. Although I say value and hue, it is assumed at this point that value should be spot on if prior mixing was completed accurately meaning that targeting the Munsell neutral hue is all that is needed. The photo details roughly the mid point in mixing. Note the three piles of paint: cool, true N8 and warm. In this case there was a bit of umber/left over. The true N8 mix was then tubed up.