Turpentine enters in the paste for one great and principal end, viz. to keep the particles of the paste a little asunder, and facilitate to the wax a free passage through it; for the particles of turpentine diffused through the paste, in melting, when the picture is brought near the fire, open so many equi-distant channels for the wax, which, by this means, can penetrate freely and uniformly, and diffuse itself over the whole in equal proportion; without the turpentine it would not succeed so well; the wax would only come through here and there; the colours would in a manner be calcined before a sufficient quantity could penetrate to secure them; for though there will be wax enough for the first fixing, yet, to alter or retouch, or where an extraordinary great body of colours might be employed, there might be a deficiency of wax, which cannot be supplied otherwise than by laying it on, on the back, and if it could not work its passage through the whole might miscarry.[14]
As few artists compose the crayons themselves, and as inserting directions for that purpose would have swelled this treatise too much; the author, for the conveniency of all practitioners has given the recipe of proportion for composing every tint for what it is to be when fixed, to Mr. Sandys, colour-merchant, in Dirty-lane Longacre, of whom perfect sets may be had; and as the author has communicated the recipe, for binding the most difficult colours,[15] for the benefit of the art, without fee or reward whatsoever, those crayons will be sold at the usual price. At the above place, may be had cloth or paper ready prepared on short notice.
However, if any artist should chuse to prepare the crayons himself, he will do well to leave out the pipe-clay, fullers-earth, chalk, &c. as much as possible, and mix his tints as usual. The standard recommended under Art. II. [page 29], [30]. and explained [page 55], [56]. will be of service for ascertaining beforehand the value of each tint.
If any crayon prepared for the old way, should prove too hard for this, as may be the case with vermilion, bice, verditer, and the other looser colours, in whose composition enters a little paste to bind them, sprinkle those crayons with a brush dipt in spirit of wine, and they will become manageable.
General Remarks
On the apparent characters of encaustic paintings, on wax and varnish.
The principal apparent characters of an encaustic painting are,
1. The colours have all the airiness of water colours, and all the strength of paintings in oil, without partaking of the apparent character, or defects of either.
2. You may look at and enjoy a picture in any light; the colours are bright, fresh and lively without glaring. They require no varnish.
3. The colours are firm, without being brittle, and will bear scratching without receiving any harm.