Dictionarium polygraphicum. Of making white colours.

Dictionarium Polygraphicum:
Or, The Whole Body of Arts Regularly Digested.
Vol II.
London: Printed for C. Hitch and C. Davis in Pater-noster Row, and S. Austen in St. Paul's Church Yard. MDCCXXXV.
1735
A fine white for water-colours.
Dissolve filings of fine silver, or leaf-silver, in aqua-fortis or spirit of nitre, then evaporate the aqua-fortis till it looks like crystals in the bottom of the glass: decant the other part of the aqua-fortis, and wash the silver five or six times in common water, till it be freed from the aqua-fortis, which may be known by tasting it; then dry it for use. It must be used with gum-water, with a little water of sugar-candy.

An incomparable fine white lead.
Take choice white lead, grind it well upon a porphyry with vinegar, and it will turn blackish; thsn take a pot full of wares, and wash the white lead in it very well; let it settle, and pour off the water; grind it again with vinegar; repeat this once or twice, and you will have an excellent white, both for watercolours and painting in oil.

To make the white to be used with glove-leather size, for making a very fine polish'd gold.
Having made the size, scrape some crayon white with a knife, or grind it upon a marble; melt and heat your size as hot as can be, then take it off the fire, and put in white enough to make it of the consistence of pap, let it stand to infuse for a quarter of an hour; then stir and mix it with a bog's hair-brush.

Add more size to this white, to make it thinner, for the first and second goings over.

Let your first lay be dry before you go over it with a second; and if it be wood you work upon, you ought to repeat it twelve times; but if it be paste-board, six or seven will be sufficient.

When this has been done, dip a soft brush in water, and strain it between your fingers, and brush your work over with it, to cause it to lie more smooth and even. As soon as your brush is full of white, you must wash it over again, and even change the water; when it is too white, you may use a wet cloth instead of a brush.

When the work is smooth and even, let it stand to dry; and when it is dry, rub it over with shave grafs, or a piece of new cloth, to make it the kinder.