PRINTING INK is made of oil-var nish and fine lampblack. The varnish is made by heating pure linseed oil in a copper till it will light with a piece of lighted paper. It is then made to burn away to three quarters, to two thirds and one half for varnishes, of various consistence. The lampblack is the soot of turpentine lamps, burnt in a close chamber, and the soot collected on flannels which line the room, and from to time are beat out. In a large way the oil is not burnt, but evap orated, at nearly a boiling heat, to a thick consistence ; lampblack is often made by burning pitch, resin, &c., and collect ing the soot in a horizontal chimney, which passes into a chamber hung with coarse cloths or flannels. The ink is made by gradually triturating the black with the varnish on a stone with a muller, but in the large way this is done by a horse-power with a wheel, in the manner of color-grinding. Balsam copaiba, soap, resin, and indigo are used by some as in gredients in the ink.
After the smoke begins to rise from the boiling oil, a bit of burning paper stuck in the cleft end of a long stick should be applied to the surface, to set it on fire, as soon as the vapor will burn ; and the flame should be allowed to continue (the pot being meanwhile removed from opt the fire, or the fire taken from under the pot), tin a sample of the varnish, cooled upon a pallet-knife, draws out into strings of about half an inch long between the fingers. To six quarts of linseed oil thus treated, six pounds of resin should be gradually as soon as the froth of the ebullition has subsided. Whenever the resin is dissolved, one pound and three quarters of dry brown soap, of the best quality, cut into slices, is to be in troduced cautiously, for its water of com bination causes a violent intumescence.
Both the resin and soap should be well stirred with the spatula. The pot is to be now set upon the fire, in order to complete the combination of all the constituents. Put next of well ground indigo and Prussian blue, each 21 ounces, Into an earthen pan, sufficiently large to hold all the ink, along with 4 pounds of the best mineral lampblack, and then 8h pounds of good vegetable lampblack ; then add tne good varnish by slow degrees, care fully stirring, to produce a perfect incor poration of all the ingredients. This mixture is next to be subjected to a mill, or slab and muller, till it be levigated in to a smooth uniform paste.
One pound of a superfine printing ink may be made by the following recipe of Mr. Savage :—Balsam copaiba, 9 oz. ; lampblack, 8 oz. ; indigo and Prussian blue, together, p. req. II oz.; Indian red, oz.; turpentine (yellow) soap, dry, 8 oz. This mixture is to be ground upon a slab, with a mullet., to an impalpable smooth ness. The pigments used for colored printing inks are, carmine, lakes, vermil ion, red lead, Indian red, Venetian red, chrome yellow, chrome red or orange, burnt terra di Sienna, gall-stone, Roman ochre, yellow ochre, verdigris, blues and yellows mixed for greens, indigo, Prus sian blue, Antwerp blue, lustre, umber, sepia, browns mixed with Venetian red, &c.