A technical dictionary of printmaking, André Béguin. Back to Main Page of the "Printmaking dictionary" Tusche or chemical ink C. CHEMICAL INKS. Since the times of Senefelder chemical ink has been used to write or draw on stone, zinc, or aluminium (three lithographic technique surfaces). This kind of ink must not be confused with the ink used to print lithographies. "Chemical ink, which one may also call greasy or alcaline ink, derives its name from the fact that it contains a mixture of greasy, resinous and alcaline parts. It is one of the most important an necessary materials for a lithographer" ( Senefelder, The Art of Lithography). The essential components of chemical ink are tallow, wax, and resin. The reader should remember that the only reason black pigment is added to this ink is to permit the person making the drawing to see his work as it progresses. Pigment serves no other purpose in this ink. The greasy substances mentioned above are not soluble in water and, in order to make them easier to work with, some soap must be added to them. When the drawing on the stone has been completed it is then washed with an acidulous preparation which neutralizes the alcaline substances and makes the greasy elements become insoluble again. The tallow used for chemical ink is often sheep tallow since it contains very little oil. The grease content of the ink is what makes it solid but if the content is excessive the ink becomes too soft. Wax, on the other hand, gives consistency to the ink and prevents the tallow from spreading. However, if too much wax is used the ink will dry too fast and become brittle. In such a case the ink must be continually thinned with water or oil. Resin gives fluidity to the ink (after being saponified) but if it is used in excess it will dry the ink and makes it insoluble when cold. Chemical ink must be strong, in other words even a large amount of impressions must not affect the lines. Such ink must be resistant in order to protect the stone from the acids. An excessive use of soap will reinforce the ink but will also make it become quite gluey. In order to make chemical ink, melt wax and tallow in a cast iron pot which must not be more than one-third full. When the mixture reaches about 200°C (about 400°F) add soap flakes and stir briskly. The mixture must be hot enough that it will catch fire when touched with a burning match. While the mixture is burning mix in the resin (shellac). Then smother the fire by covering the pot with a lid and then proceed to add the black pigment. The mixture should then become quite pasty and can be put into boxes and covered with tin foil. The ink thus prepared can be dissolved in either distilled water or oil, depending on the ingredients used. In order to obtain a liquid ink mix it (when still pasty) with some boiling hot distilled water. Solid ink can be diluted in much the same way as India ink using a liquid and a bowl. Chemical ink may be applied with either a brush or a pen. Since the times of Senefelder a variety of recipes for chemical ink have been invented. Thirteen well known recipes are given below. The table containing these recipes was sent by the Lorilleux Company of Bruxelles to the Belgian Ministry of Economic Affairs in 1920 when the Ministry undertook to publish a monograph on lithography. The amounts are all in grams (1 gram= 0.035 ounces avoirdupois or 15.4 grains). ingredients 1 2 3 4 5 6 7 8 9 10 11 12 13 white wax 100 100 100 100 100 100 100 100 100 100 100 yellow wax 100 yellow soap, Marseille soap 30 54 325 100 20 45 50 25 160 250 100 50 100 lac 200 70 150 100 100 25 140 25 125 125 75 gum mastic in drops 10 25 20 25 25 50 purified tallow 20 75 100 34 25 160 75 75 75 100 lamp black 5 22 75 7 7 13 25 25 50 50 25 25 25 soda 20 Venice turpentine 13 13 21 olive oil 12 Recipe n.3 is Lemercier's, n.10 is a German recipe for brush work, n.11 is the Doyen recipe, n.12 is the Knecht-Senefelder recipe, and n.13 is the Chevalier and Langlumé recipe. Lithographic crayons are made with much the same ingredients as chemical ink but they are not water soluble. Chemical ink can also be used in serigraphy and in manual screen processes, as a kind of ground in etching and in a zincographic* process which creates relief blocks using electrolysis [galvanography, electrotyping] Back to Main Page of the "Printmaking dictionary"