SECTION III.
Of the colours fit to be ufed in frefco ; or, painting with fize j and the manner of mixing or compounding , them with the proper vehicles.
BY frefco painting was originally meant all 1 paintings on walls, or other parts ofbuildings expofed to the open air ; but at pre-lent it ngnifies in common language the grofier
paintings in water, where fize is ufed. Thefame colours which are employed in miniaturepainting, may be ufed in this kind with fize:only this method being principally onfined tofeenes and grofier forts of work, where theefieft depends more on the perfpeddve art andthe oppofition of the colours, than on theirbrightnefs, the dearer kinds are wholly omit-ted, or fparingly ufed.
The belt method of compounding the colours with the vehicles, is to mix the fize in water; then to levigate the colours in part of it; and afterwards to put each kind in a proper pot; adding as much more of the. melted fize as will bring it to a due confidence for working; and mixing the whole well together in the pot with a proper brufh, or wooden ipatula. If the quantity of water originally put to the fize, do not render it fuffidently fluid for grinding the colours, the fault may be eafily remedied by adding warm water to it; and the fame may be done likewife, if, after the mixture of colours, the whole be found too ftiff for working.
The compositions of the colours and fize muft be prevented from drying, by tying bladders over the pots, or fome other fuch means $ for when once they are grown dry, they cannot be brought again to a working date without difficulty and trouble.
Though the grounds and the laying in, and grofier parts of this kind of painting, be done by this mixture of the colours with fize; yet in higher finifhed works, that require die finer colours, the more delicate parts may be belt executed by ufing the gum-waters or if- ing-glafs, as above directed in miniature painting : by which means the mixing up greater quantities of the dear colours may be avoided, though otherwife necefiary; as it is impracticable to keep minute quantities from drying; which, in the fize, renders them unfit for working, till they are again reduced to proper condition by,means of heat; but, in the others, is not attended with the lead inconvenience.