Part 263

The following inks are developed by exposure to the action of reagents:

I.—Upon writing with a very clear solution of starch on paper that contains but little sizing, and submitting the dry characters to the vapor of iodine (or passing over them a weak solution of potassium iodide), the writing becomes blue, and disappears under the action of a solution of hyposulphite of soda (1 in 1,000).

II.—Characters written with a weak solution of the soluble chloride of platinum or iridium become black when the paper is submitted to mercurial vapor. This ink may be used for marking linen, as it is indelible.

III.—Sulphate of copper in very dilute solution will produce an invisible writing, which may be turned light blue by vapors of ammonia.

IV.—Soluble compounds of antimony will become red by hydrogen sulphide vapor.

V.—Soluble compounds of arsenic and of peroxide of tin will become yellow by the same vapor.

VI.—An acid solution of iron chloride is diluted until the writing is invisible when dry. This writing has the property of becoming red by sulphocyanide vapors (arising from the action of sulphuric acid on potassium sulphocyanide in a long-necked flask), and it disappears {413} by ammonia, and may alternately be made to appear and disappear by these two vapors.

VII.—Write with a solution of paraffine in benzol. When the solvent has evaporated, the paraffine is invisible, but becomes visible on being dusted with lampblack or powdered graphite or smoking over a candle flame.

VIII.—Dissolve 1 part of a lead salt, 0.1 part of uranium acetate, and the same quantity of bismuth citrate in 100 parts of water. Then add, drop by drop, a solution of sal ammoniac until the whole becomes transparent. Afterwards, mix with a few drops of gum arabic. To reveal the characters traced with this ink, expose them to the fumes of sulphuric acid, which turns them immediately to a dark brown. The characters fade away in a few minutes, but can be renewed by a slight washing with very dilute nitric acid.

«TYPEWRITER RIBBON INKS.»

I.—Take vaseline (petrolatum) of high boiling point, melt it on a water bath or slow fire, and incorporate by constant stirring as much lamp or powdered drop black as it will take up without becoming granular. If the vaseline remains in excess, the print is liable to have a greasy outline; if the color is in excess, the print will not be clear. Remove the mixture from the fire, and while it is cooling mix equal parts of petroleum, benzine, and rectified oil of turpentine, in which dissolve the fatty ink, introduced in small portions, by constant agitation. The volatile solvents should be in such quantity that the fluid ink is of the consistence of fresh oil paint. One secret of success lies in the proper application of the ink to the ribbon. Wind the ribbon on a piece of cardboard, spread on a table several layers of newspaper, then unwind the ribbon in such lengths as may be most convenient, and lay it flat on the paper. Apply the ink, after agitation, by means of a soft brush, and rub it well into the interstices of the ribbon with a toothbrush. Hardly any ink should remain visible on the surface. For colored inks use Prussian blue, red lead, etc., and especially the aniline colors.

II.—Aniline black 1⁠/⁠2 ounce Pure alcohol 15 ounces Concentrated glycerine 15 ounces

Dissolve the aniline black in the alcohol, and add the glycerine. Ink as before. The aniline inks containing glycerine are copying inks.

III.—Alcohol 2 ounces Aniline color 1⁠/⁠4 ounce Water 2 ounces Glycerine 4 ounces

Dissolve the aniline in the alcohol and add the water and glycerine.

IV.—Castor oil 2 ounces Cassia oil 1⁠/⁠2 ounce Carbolic acid 1⁠/⁠2 ounce

Warm them together and add 1 ounce of aniline color. Indelible typewriter inks may be made by using lampblack in place of the aniline, mixing it with soft petrolatum and dissolving the cooled mass in a mixture of equal parts of benzine and turpentine.

«COLORING AGENTS:»

Red.—

I.—Bordeaux red, O. S. 15 parts Aniline red, O. S. 15 parts Crude oleic acid 45 parts Castor oil enough to make 1,000 parts

Rub the colors up with the oleic acid, add the oil, warming the whole to 100° to 110° F. (not higher), under constant stirring. If the color is not sufficiently intense for your purposes, rub up a trifle more of it with oleic acid, and add it to the ink. By a little experimentation you can get an ink exactly to your desire in the matter.

Blue-Black.—

II.—Aniline black, O. S. 5 parts Oleic acid, crude 5 parts Castor oil, quantity sufficient to 100 parts.

Violet.—

III.—Aniline violet, O. S. 3 parts Crude oleic acid 5 parts Castor oil, quantity sufficient to 100 parts.

The penetration of the ink may be increased ad libitum by the addition of a few drops of absolute alcohol, or, better, of benzol.

«Reinking.»—For reinking ribbons use the following recipe for black: One ounce aniline black; 15 ounces pure grain alcohol; 15 ounces concentrated glycerine. Dissolve the aniline black in the alcohol and then add the glycerine. For blue use Prussian blue, and for red use red lead instead of the aniline black. This ink is also good for rubber stamp pads. {414}

«WRITING INKS.»