US1153131A - Production of safety-grounds for documents. - Google Patents

Description

, C. G. PETIT.

PRODUCTION OF SAFETY GROUNDS FOR DOCUMENTS.

APPLICATION FILED OCT. 11. 1911.

,153,131 Patentedsept. 7, 1915.

in d 0 M/VE/VTW? WITNE5$E5 I CHHFLES GU/ALaUME P5717 COLUMBIA PLANOGRAPH c0.. WASHINGTON, D. c.

; rien CHARLES GUILLAUME'VEETIT, or BELLEVUE, FRANCE.

rnonncrron or sarnrr-enonnns rortnoourrnn'rs.

Specification of Letters Patent. at nted t, 7, 5,

Application filed October 11, 1911. SrialNo. 654,428. i

To all whom it may concern Be'it known that 1, CHARLES GUILLAUME PETIT, of Rue Dumont dUrville, Bellevue, Department of Seine et Oise, Republic of France, have invented certain new and useful Improvements lll'filiGPIOdllClZlOIl of Safety-Grounds for Documents, of; which the following is a full, clear, and exact description. I V

This invention relates to safety-grounds for bank-notes, share-certificates and other valuable papers or documents of any kind.

It consists in reproducing by means of two or more half-tone or line-screens of different line-inclinationsor different designs and with different lengths of exposure, a half-tone pattern arranged so as to present most diverse gradations in such a way as to vary the thickening or thinning of the lines, dots 0r grains furnished by the screens, then forming by means of each photographic print so obtained blocks, plates or reproductions adapted to print by any usual method, and lastly printing the safetyground my means of the latter withcolors selected so that decomposition of the'image obtained becomes substantially impossible.

By reason of the possibility of varying at will the gradation of'the half-tones of the pattern and therefore the thickness of the screened lines, dots or grains, and owing'to' the dlfierence of inclination or deslgn of the screens, there are obtained new decorative effects which can be varied at will, and the reproduction of which is impossible; the invention, therefore, offers complete protection against falsifications or forgery.

For the preparation of the pattern serving to obtain the variable thickening or thinning of the lines, dots or grains of the screens, there is employed the following process which by reason ofits simplicity, its low cost of. working and the guarantees against falsification which it presents, forms an essential part of the invention. It consists in employing a nonactinic (black, yellow, orange, etc.)' paper or equivalent material which is perforated more or less-symmetrically to produce a design which, although coarse, may yet be agreeable'to the eye. The perforations are formed in the paper or other material in any suitable manner, for example bymeans of a hollow punch, but the perforations are made of diflerent sizes and of different shapes in;

order that in the operation to be hereafter described the light may act to a greater or less degree but for the same length of time upon the sensitive preparations. The perforated paper so obtained is used like a photographic negative which it is desired to reproduce upon sensitized paper; that is to Y say, it is placed in a printing-frame, but very slightly separated from the sensitized paper by means of an intermediate sheet of clear glass. A ground glass is placed at the front of the printing frame and the wholeis exposed to the light of the sun or of one or more electric'lamps, taking care not to leave the frame more than a few seconds in the same position and taking away the ground glass from time to time. I

The intensity of the image is judgedas is usual in printing on paper, by opening the frame whenit is thought that the de-' sired effect is nearly reached. The light passing through the perforations in the dif- I ferentpositions in which the printing frame is held under the source of light causes an lnnumerable quantity of tones of, an original decorative effect, because the luminous rays falling sometimes directly, sometimes obliquely, upon the perforations produce at certain points crossings of intense light upon the sensitive surface, while other parts are less exposed and others again are wholly concealed. 'The whole of this operation with ground glass, direct light and movement of the frame and of the glass is intended to obscure or render indefinite the image of the perforation in such a way that sensitized paper is withdrawn from the Q frame, washed and fixed in the usual man- It is evident that the imageobtained ner. in the manner described can in no way berepeated a second time, especially if theperforated paper is destroyed after a satisfactory decorative result has been obtained.

protection against falsification. The pattern thus formed is twice reproduced at different' angles by means of copying linescreens and by the usual printing methods (copper-plate, typography, lithography,

etc), The result is obtained by means of l Consequently the methodaflords a complete a substantially differing times of exposure for the preparation of the screened negative blocks, so that one of them reproduces the whole of the image and the other givesonly the dark half-tones and the blocks. In these conditions when printing takes place, if one of the'bloclis'is printed for example in yellow and the other in red, the resulting orange will be formed only inthe dark half In the accompanying drawing is shown in cross section a printing frame by which the pattern may be obtained. 1

As here shown the frame F) has an inwardly projecting head at the front in which a horizontal slot is provided to permit the temporaryadjustment of a sheet of ground glass a. A sheet of clear glass crests against the inner face of the bead and-supports the perforated negative d. Several sheets of clear glass 0, 6 6 separate this from this sheet f of sensitized paper, which is held in position .by'the backof the frame 9.

The invention is not limited to the above described details of execution. ple, two of more difierently perforated pat- ,terns might be used and the screened or half-tone blocks obtained separately therefrom might be printed one upon the other.

Again the perforated patterns might be replaced by photographic prints or negatives or any compositions adapted to serve as such, maintained at a distance from the sensitized paper. Moreover, there may be For examprinted upon the safety-grounds obtained in the manner above described, either at once or at the same time as the letter-press,

any border, ornamentation or the like that may be desired as a third impression.

Having thus described my invention, what I'claim' as such and desire to secure by Letters Patent is 1. As a new article of manufacture, a

sheet of suitable material having printed thereon a safety ground of the character described comprising superposed impressions of indeterminate iris-like outlines of diverse light gradat1ons,sa1d impresslons being in different colors and screen schemes, the

Whole forming upon the sheet an image having blended colors and indeterminate outlines practically incapable of lineal decomposltion.

'2. As a new article of manufacture, a

sheet of suitable material having printed thereon a safety ground for bank notes and the like, comprising a halftone composed of a plurality of superposed images each of indefinite and vague, and uncertain outline havin li ht 'radations var in from osi- D b t) the and strong effects to vague and confused and disappearing efiects, the super.-

posedimages being differently colored and the colors effecting a finished blend.

In testimony whereof I have signed my name to this specification, in the presence of two subscribing witnesses.

CHARLES GUILLAUME PETIT.

Witnesses: Q JACQUES LEJEUNE,

y LEON PEILLETL Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

' Washington, D. Q?! A v

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