SIZE. A kind of weak glue, used in many trades; it is made of the shreds and parings of leather, parchment, or vellum, boiled in water, and strained. Common size is made of leather, boiled in water till it becomes of a viscid con sistence. If it is wanted in painting for nicer purposes, it should be prepared by taking any quantity of the shreds or cuttings of glovers' leather, and putting to each pound a gallon of water ; let these be boiled for six or eight hours, supplying water, so that it may not diminish to less than two quarts ; then strain the hot fluid through a flannel, and afterwards evaporate it, till it is of the consistence of a jelly when cold. The size used in burnish gilding, and made of cuttings of parchment, is prepared much after the same mannet.
Gold-size is directed to be made thus : " Of gum-anime and asphaltum, take each one ounce; minium litharge of gold and amber, of each half an ounce; reduce all into a very fine powder, and add to them four ounces of linseed oil and eight ounces of drying oil ; digest them over a gentle fire that does not flame, so that the mixture may only simmer, but not boil, lest it should run over and set the house on fire; stir it constantly with a stick till all the ingredients are dissolved and incorporated, and do not leave off stirring till it becomes thick and ropy ; after being sufficiently boiled, let it stand till it is almost cold, and then strain it through a coarse linen cloth, and keep it for use.
To prepare it for working, put what quantity you please in a horse-muscle shell, adding as much oil of turpentine as will dissolve it; and making it as thin as the bottom of your seed-lac varnish, hold it over a candle, and then strain it through a linen rag into another shell ; add to these as much vermillion as will make it of a darkish red ; if it is too thick for drawing, thin it with some oil of turpentine. The chief use of this size is for laying on metals. The best gold size for burnishing is thus made : take fine bole, what quantity you please; grind it finely on a piece of marble, then scrape into it a little beef suet; grind all well together, after which mix in a small proportion of parchment-size, with a double proportion of water, and it is done." Silver-size is made of tobacco-pipe clay in fine powder, into which is scraped some black-lead and a little Genoa soap ; all is then ground together with parchment, as already directed.