Use this range of Clae engobes to colour your clay.  These engobes are for use on raw clay, are smoother than coloured slips (offering a more refined finish), and are stable in a glaze firing.
Clae has curated this New Zealand inspired colour range especially.
 
The engobes come in 100ml jars, wide enough for you to get most sized brushes into.  Make sure that you mix the engobe well before use, and if too stiff, add a few drops of water to thin.
 
The engobes are tested at 1240 deg C.