To Prevent Mold in Ink.—The ad dition of a little alcohol or a few drops of any essential oil or a few cloves will prevent mold.
Or add a few drops of salicylic acid or corrosive sublimate or carbolic acid, but do not add metallic acids to inks containing aniline dyes.
To Prevent Ink from Thickening. —As inks thicken by the evaporation of the liquids with which they are diluted, the only way to protect them is to keep them covered from the air. Hence the use of inkstands with ta pering funnels of glass or hard rub ber is advisable. If the ink becomes too thick to write smoothly, or if, when a bottle has been exhausted, a residue of black sediment is left, it may be diluted with clear water or a small quantity of strong black coffee strained through silk or linen.
To Keep Ink from Freezing.—The addition of a small quantity of alco hol acts as a preventive.
To Restore Faded Ink. — Writing which has become partially illegible on account of age may be restored by applying carefully to the paper an in fusion of galls, or a solution of prus siate of potash slightly acidulated with dilute sulphuric or muriatic acid. These substances have the property of turning iron-gall inks black.
To Remove Oiliness from Ink.—If the action of the air causes ink to become oily, ropy, or stringy, add a little oxgall or vinegar.
Printer's Ink is a carbon ink mixed with oils or resins. The carbon is usually lampblack or ivory black mixed with a little indigo or Prussian blue. The oil is usually boiled linseed oil or nut oil. Other ingredients are rosin, turpentine, balsam of copaiba, and yellow soap. Great care is required to produce the finest grades of ink, and printer's inks vary greatly in qual ity and price. The methods of prep aration are trade secrets, and printers rarely attempt to make the better grades of ink for themselves.
Colored printing inks are made by using various colored pigments in place of carbon.
Bronze and other metallic effects are produced by printing with a near ly colorless glue size, and sprinkling the metallic powder on the surface while it is sticky.
Printing Ink. — Grind in a paint mill or with a marble mortar and pestle 9 ounces of balsam of copaiba, 4 ounces of finest lampblack, 1 ounce of powdered indigo, and 3 ounces of hard, dry yellow soap. Heat a quan tity of linseed oil in an iron kettle until it begins to boil. Remove from the fire and kindle the escaping vapor. Allow it to burn until the oil becomes stringy when lifted with a stirrer. Then add to each quart of oil 1 pound of pulverized black rosin. Dissolve
with gentle heat and stir in 4i ounces of dry yellow-soap shavings to each quart. Melt these together with gen tle heat. Measure for every pound of rosin employed 1 ounce of indigo, 1 ounce of Prussian blue, and 18 ounces of lampblack. Pour the melt ed mixture over these pigments, mix, and grind in a paint mill.
Dryers for Printer's Ink. — One ounce of beeswax, ounce of gum arabic dissolved to a thin mucilage with acetic acid, ounce of japan, and ounce of asphaltum varnish.
Add the above to 1 pound of printer's ink.
Lithographic Ink. — Melt together with gentle heat 3 ounces of shellac, 4 ounces of castile soap, 2 ounces of white wax, and 2 ounces of tallow. Add 3 tablespoonfuls of gum san darac dissolved in 3 tablespoonfuls of alcohol, and stir in ivory black or the best lampblack to color.
To Remove Ink Stains.—The arti cle to use depends entirely on the nature of the ink. For a logwood ink stain, use dilute muriatic acid, 1 part of acid to 10 parts of water. This removes the stain, first turning it red; but it converts the stain of red eosin ink to an insoluble brick-red substance, and a nigrosine ink stain to an indelible blue-black dye.
For an iron-gall ink, use oxgall or mineral acids, as muriatic, sulphuric, and the like. These decompose the black tannate of iron, but have no ef fect on the indigo and aniline blues which are added to most modern inks, especially the blue-black writing fluids.
Hence the first step is to find out what the ink contains. If convenient, this may be done by putting a few drops on a piece of cloth, and testing with that; meantime taking measures to prevent the stain from spreading. First dry the sample and attack it with water. If the ink contains nigrosine, it will dissolve in water and the stain will spread. In that case use an alkali, as baking soda, cover ing the stain thickly and moistening it with water. If the ink does not run, it is probably iron-gall or ]ogwood ink, hence an acid may be tried, but if the acid does not succeed, try soda or other alkali.
On white fabrics, the best way to remove ink stains is to cover the spot with chloride of lime and moisten with dilute muriatic acid. This sets the chlorine free to attack the stain. Ni trate of silver stains may be removed by cyanide of potassium, but this must be used with great care, as it is very poisonous.
For colored fabrics pyrophosphate of soda may be tried. Fabrics should be immediately washed with clear water after the stain has been re moved.