Use finely powdered colours, and mix them to the consistence of cream,
with the following medium:--Mix the white of an egg with 2 oz. of pure
distilled vinegar; put them into a bottle and shake them well together
whenever you are about to mix any colours with it: or mix the colours
with parchment size warmed; use while warm: or mix them with a weak
solution of gum arabic; and, in either case, varnish them with a quick
drying pale varnish. Oil colours will not do for painting this kind of
materials: any of the above mediums, properly prepared, will answer
well. Gilding may be interspersed with brilliant effect.