HEAD FUR I did the fur on the top of the head a slightly different colour  than the body fur. Shade layer; Uniform Grey mixed with  Matt Black, followed more Uniform Grey in that mix, and  finished off with a highlight of pure Uniform Grey.   BEARD Shade layer, Desert Yellow, then a mix of Desert Yellow and  Daemonic Yellow, finished with a very fine highlight of  Desert Yellow and Daemonic Yellow plus Matt White.  EYES Unlike baboons, you can see some of the whites of the  mandrills’ eyes, and the iris is a very distinctive burnt orange.  So I used Matt White for the whites, Lava Orange for the iris  and Matt Black for the pupil, fortunately the eyes are a bit  oversized on the models making them a little easier to paint  than would otherwise be the case. VARNISH Make sure all the paint on the model is thoroughly dry before  commencing varnishing. Gloss The models were then given a coat of Humbrol polyurethane  gloss varnish and set aside for 24 hours to dry completely. Be  careful not to let the varnish pool, especially under the kilts  and between the spears. You don’t need a very thick coat of  varnish. Matt Then they were given two coats of Anti-Shine Matt Varnish.  Be even more careful when painting on the matt varnish.  When applying the matt, brush it out well from any nooks and  crannies where it is likely to collect and pool.  
Above. The head fur, Shade layer; Uniform Grey mixed with Matt Black.
BASING Now normally I would base up the models to finish them off,  but that is going to be another article later!