Treatment of India Ink Drawings.
An easy method for rendering drawings in Indian ink insensible to water, and thus preventing the ink from running when the drawing has to be colored and the lines are very thick:—To the water in which the ink has to be rubbed, is added a weak solution of bichromate of potash of about 2 per cent. The animal gum contained in the Indian ink combines with the bichrome, and becomes insoluble under the influence of light.
Black Ink.
To make a black ink for fountain pens, add 1 part of nigrosein to 50 parts of hot water; agitate well at intervals; let it cool, and after twelve hours filter through a fine linen cloth, and add a few drops of carbolic acid to each pint. This may be diluted with three times its volume of water, and still form a good ink for ordinary pens.
Ink for Rubber Stamps.
Aniline (red violet), 16 parts; boiling distilled water, 80 parts; glycerine, 7 parts; molasses, 3 parts.
Cardinal Ink.
Improved cardinal ink for draughtsmen is made as follows:—Triturate 1 gram of pure carmine with 15 grams of acetate ammonia solution and an equal quantity of distilled water, in a porcelain mortar, and allow the whole to stand for some time. In this way a portion of the alumina which is combined with the carmine dye is taken up by the acetate acid of the ammonia salt and separates as precipitate, while the pure pigment of the cochineal remains dissolved in the half saturated ammonia. It is now filtered and a few drops of pure white sugar syrup added to thicken it. In this way an excellent red drawing ink is obtained, which holds its color a long time. A solution of gum arabic cannot be employed to thicken this ink, as it still contains some acetic acid, which would coagulate the bassorine, one of the natural constituents of gum arabic.