Williamsburg Oil Colour Neutral Gray 2 S1 150ml

PW 6 - Titanium Dioxide Rutile
PBk 6 - Nearly Pure Amorphous Carbon
PBr 7 - Natural Iron Oxide
PY 43 - Natural Hydrated Iron Oxide
Williamsburg Special Edition Neutral Grays (N2, N4, N6 and N8), ground in alkali-refined linseed oil and using a combination of Titanium White, Lamp Black, and small touches of various iron oxides (burnt umber, burnt sienna, raw sienna) to pull the otherwise too-cool mixtures back towards neutral.  

The Williamsburg Grays match the Munsell values nearly flawlessly across the spectrum.