For a black color for printing, 25 parts paraffine oil and 45 parts resin are mixed, either by melting at 80°C., or by mechanical means at the ordinary temperature. To this mass 15 parts of black are added. For printing machines, the mixture is composed of 40 parts of resin only, instead of 45. Resin can, in some cases, be replaced by dammar. Other colors are mixed by substituting the equivalent of the color to the black. When cheapness has to be considered, paraffine oil can be substituted by resinous oil, and resin by Burgundy resin, etc.
How to Dye Parchment Blue or Red.
Parchment can be dyed green, blue or red. To dye it blue, use the following process:—Dissolve verdigris in vinegar; heat the solution, and apply it by means of a brush on the parchment, till it takes a nice green color. The blue color is then obtained by applying on the parchment thus prepared a solution of carbonate of potash. Use two ounces for one gallon of water. Another method is to cover it by means of a brush with aquafortis, in which copper dust has been dissolved. The potash solution is then applied as before, till the required shade is obtained. Another method is by using the following solution:—Indigo, 5 ozs.; white wood, 10 ozs.; alum, 1 oz.; water, 50 ozs. Red:—The parchment is dyed red by applying with a brush a cold logwood solution, and then using a 3 per cent potash solution.
To Make Paper Fire and Water-proof.
To make paper fire and water-proof, mix two-thirds ordinary paper-pulp with one-third asbestos. Steep in a solution of common salt and alum, and after being made into paper coat with an alcoholic solution of shellac. By plunging a sheet of paper into an ammoniacal solution of copper for an instant, then passing it between the cylinders and drying it, it is rendered entirely impermeable to water, and may even be boiled without disintegrating. Two, three, or any number of sheets rolled together become permanently adherent, and form a material having the strength of wood. By the interposition of cloth or any kind of fiber between the layers, the strength is greatly increased.
A New Blotting Paper.
A blotting paper that will not only dry the blot, but bleach the remainder of it can be made by passing ordinary blotting paper or card through a concentrated solution of oxalic acid. Care must be taken that no crystals appear, which would injure the porosity of the paper.
Impermeable Paper.
To make impermeable paper, prepare the two following baths: (1) alum, 25 ozs.; white soap, 12½ ozs.; water, 100 ozs. (2) gum arabic, 6 ozs.; Colle de Flandre, 18 ozs.; water, 100 ozs. Place the sheet of paper in the first bath to be well impregnated. In this bath the paper is left only for a short time. It is then dried and dipped in the second bath, the same precautions being used as for the first bath. When dry, the paper is hot-pressed in order to render it uniform.