Safe′ty-pa′per.
A paper chemically or mechanically prepared, so that its color or texture will be changed by being tampered with; or a paper so difficult of production as to give an additional measure of safety.
Of safety-papers there are several kinds:—
1. Paper made with distinguishing marks to indicate proprietorship, as with the Bank of England water-mark, to imitate which is felony.
Or the paper of the
United States currency, which has silk fibers united with the pulp, the imitation of which is felony.
2. Paper made with layers or materials which are disturbed by erasure or chemical discharge of written or printed contents, so as to prevent fraudulent tampering.
3. Paper made of peculiar materials or color, to prevent copying by photographic means.
A number of processes may be cited: —
One kind is made of a pulp tinged with a stain easily affected by chlorine, acids, or alkalies, and is made into sheets as usual.
Water-marks made by wires twined among the meshes of the wire cloth on which the paper is made See water-mark.
Threads embodied in the web of the paper.
Colored threads systematically arranged were formerly used in
England for postoffice envelopes and exchequer bills.
Silken fibers mixed with the pulp or dusted upon it in process of formation; as used in the
United States paper currency.
Tigere, 1817.
Treating the pulp or the paper, previous to sizing, with solution of prussiate of potash.
Sir Wm. Congreve, 1819.
A colored layer of pulp in combination with white layers.
Priating upon one sheet and covering with an outer layer plain or water-marked.
Glynn and
Appel, 1821 Mixing a copper salt in the pulp and afterward adding an alkali or alkaline salt to produce a copious precipitate.
The pulp is then wished, made into paper and dipped in a saponaceous compound.
Stevenson, 1837.
Incorporating into paper a metallic base, as manganese, and a neutral compound, as prussiate of potash, to protect writing from being tampered with.
Varnham, 1845.
A paper consisting of a white sheet or surface on one or both sides of a colored sheet.
Stones, 1851.
An iodide or bromide in connection with ferrocyanide of potassium and starch are combined with the pulp.
Johnson, 1853.
Employing the rough and irregular surface produced by the fracture of cast-iron or other brittle metal to form a water-mark for paper by taking an impression therefrom on soft metal, gutta-percha, etc., and afterward transferring it to the wire cloth on which the paper is made.
Scoatteten, 1853.
Treating paper with caoutchouc dissolved in bisulphide of carbon, to render it impermeable and to prevent erasures or chemical action.
Ross, 1854.
Water-lining or printing the denomination of the note in colors while the pulp is yet soft.
Evans, 1854 Embodying a lace or open-work fabric in the pulp when making.
Courboulay, 1855.
Mixing in the pulp, or applying to the paper salts of iodine or bromine.
Loubatieres, 1857.
Manufacturing paper in layers, any or all of which might be colored, or have impressions or conspicuous marks for preventing forgery.
Herapath, 1858.
Imbuing paper during or after its manufacture with a solution of a ferrocyanide, a ferrid-cyanide, or sulpho-cyanide of potassium, sodium, or ammonium
Seyd and
Brewer, 1858.
Applying aqueous solution of ferrocyanide of potassium or other salt, which forms an indelible compound with the ferruginous base of writing-ink
Sparre, 1850.
Opaque matter, such as Prussian
blue,
white or
red lead, insoluble in water, is stenciled on one layer of the paper web, forming a regular pattern; this is then covered by a second layer of paper.
Moss, 1859.
Coloring-matter prepared from burned china or other clay, oxide of chromium or sulphur, is combined with the pulp.
Barelay, 1859.
Incorporating with the paper, 1.
soluble ferrocyanides, ferrid-cyanides, and sulpho-cyanides of various metals, or forming dibasic salts with potassium, sodium, or ammonium, in conjunction with vegetable, animal, or metallic coloringmat-ters.
2. Salts of manganese, lead, or nickel not containing ferrocyanogen.
3.Ferrocyanides, etc., of potassium, sodium, and ammonium, in conjunction with insoluble salts of manganese, lead, or nickel.
4. Insoluble ferro-or ferrid-cyanide of manganese, or soluble sulpho-cyanide of manganese alone, or forming double salts with potassium, sodium, or ammonium.
Hooper, 1860.
Oxides of iron, either alone or dissolved in an acid, are mixed with the pulp.
Nissen, 1860.
Treating paper with a preparation of iron, together with ammonia, prussiate of potash and chlorine, while in the pulp or being sized.
Middleton, 1860. One portion of a bank-note is printed upon one sheet of thin paper and the other part on another; the two are then cemented together by india-rubber, gutta-percha, or other compound.
The interior printing is seen through its covering sheet, so that the whole device on the note appears on its face.
Olier, 1861.
Several layers of paper of various materials and colors are employed; the middle one may be colored with a deleble dye, whose color will be changed by the application of chemicals to the outer layer.
Olier, 1863.
A paper of three layers of different thicknesses, the central one having an easily removable color, and the external layers charged with silicate of magnesia or other salt.
Forster and
Draper, 1864 Treating paper during or after its manufacture with artificial ultramarine and Prussian blue or other metallic compound.
Besides these, are numerous devices for preventing copying by photographic means, certain colors being employed in parts of the genuine note which are not capable of giving a photographic image with the distinctness required.
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Safety-paper machine. |
In a paper made by the apparatus shown in
Fig. 4536, threads of rubber or gutta-percha from the roll
H are inserted between the two layers of the double web, formed by the making cylinders
B D D, compacted by the press-rolls
E E, and softened and united to the paper fiber on passing through the heated drying-cylinders
F F.
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Safety-plug for barrels. |
