US639207A - Half-tone plate and the art of making it. - Google Patents

Description

GEORGE WV. A. ABELMAN N, OF MAYW'OOD, ILLINOIS,

HALF-TONE PLATE AND THE ART OF MAKING IT.

QPEGIFICATION forming part of Letters Patent No. 639,207, dated December 19, 1899. Application filed April 17, 1899. $erial No. 713,288. (No model.)

T0 0% whom it may concern.-

Be it known that I, GEORGE W. A. ABEL- MANN, a citizen of the United States, residingin Maywood, in the county of Cook and State of Illinois, have invented a new and useful Improvement in the Art of Making Vignette- Finished Edges on Halt-Tone Copper Plates, of which the following is a specification.

My invention relates to improvements in the art of making vignette edges on half-tone plates of copper or other metal.

Heretofore a great deal of time, labor, and expense have been required to finish halftone copper plates with vignette or beveled edges, so that the margins of the print will shade off into white or blank space on the paperwithout forming an abrupt break or distinct marginal line, the work having always been done by hand by first beveling the edges of the copper plate and then laboriously engraving the beveled edges by hand with lines first in one direction and then in the cross direction corresponding to the lines on the fiat surface of the half-tone plate. In fine work it is customary to form only a single line at a time, the engraving-tool employed making a single line or mark at a time. In less careful work the shooter or tool customarily cuts five, seven, nine, or such number of lines at atime; but asthe lines require to be formed first in one direction and then at an angle, and from one hundred to two hundred lines per inch, a great deal of time and labor is necessarily required to so finish the beveled edges of the plate.

The object of my invention is to provide a simple, expeditious, and inexpensive method or process by which half-tone copper plates may be finished with vignette edges and by which also the work may be done much more perfectly than has heretofore been possible to do by hand, even when it is done with the greatest care by a skilled engraver forming a single line at a time.

My invention consists in the means 'or method I employ to practically accomplish this important result-that is to say, my invention consists in first cutting or routing away the margin of the half-tone copper plate to the depth of one-sixteeth of an inch or such matter, been customary (the sameas has heretofore where the vignette-finished edge is to be produced in the old way by beveling and engraving by hand,the square shoulder left by dercut the square shoulder left by the routing-tool to the distance of an eighth of an inch or such matter with a rotating tool, the upper surface of the undercut being prefer ably curved. This leaves the original halftone upper surface of the plate overhanging the undercut margin of the plate. I then depress, bend, or curve this overhanging por tion downward, this being preferably done by putting the half-tone plateina press with a piece of paper, preferably rather thick paper, between the half-tone plate and the platen of the press. The half-tone copper plate is thus given gradually curved or beveled edges or marginalsurfaces at the undercut portion, the original half-tone surface of the plate being preserved at the beveled or depressed marginal portion the same as in the original fiat portion of the plate. As by my invention the original half-tone surface of the plate is preserved at the beveled or depressed margin a very perfect vignette finish is thus given to the edge of the plate, so that a print formed from it will shade off to nothing without forming any marked or decided line at the margin of the print.

In the accompanying drawings, forming a part of this specification, Figure 1 is a plan View of a half-tone copper plate as produced by my invention. Fig. 2 is a partial vertical section showing the margin has been out or routed down, forming a square shoulder. Fig. 3 is a similar view showing the same after the edge of the plate has been undercut. Fig. 4 is a similar view showing the same after the overhanging undercut marginal edge of the plate has been depressed or curved or beveled down to give the vignette finish at its edge. Fig. 5 is a side elevation of a rotating tool which I prefer to employ in undercutting the edge of the.

half-tone plate. said tool, and Fig. the same. 7

In the drawings, A represents a half-tone plate of copper or other metal. a represents the flat half-tone printing-surface of the plate, and a the beveled or curved vignettefinished edge of the plate.

Fig. 6 is an edge view of 7 a bottom or plan view of copper plate after its In making the vignette-finished half-tone plate illustrated in Fig. 1 I first cut or rout away with a rotating routing-tool the margin a of the copper plate, thus forming a square shoulder a around its edge. I next, with a rotating toolsuch, for example, as illustrated in Figs. 5, 6, and 7 undercut the shoulder a thus leaving a marginal portion a of the half-tone plate unsupported or overhanging the undercut a made by the tool B. I next by putting the plate in a press or by other suitable means depress, bend, or curve downward the overhanging marginal portion a of the half-tone plate, thus leaving the original half-tone surface a upon the beveled margin the same as upon the flat portion of the plate. The-lower face Z) of the cutting-blade b of the tool 13 is preferably straight or flat and its upper surface 19 curved, so as to give a curve at to the under side or face of the overhanging portion a of the edge or margin of the plate. By giving this curved form a to the overhanging portion a the same will bend under pressure of the press on a gradual curve, and thus prevent any sharp break between the fiat surface a of the half-tone and the beveled or de pressed portion 00' thereof. In this way the necessity of beveling the square shoulder left by the routing-tool and engraving it with lines first in one direction and then in another by hand is entirely overcome, and the plates may be given a vignette finish very rapidly and cheaply and also very perfectly.

In practice the square shoulders illustrated in Fig. 2 may be undercut with a rotating It will of course be understood by those skilled in the art that in the sectional views, Figs. 2, 3, and 4, the thickness of the plate and size of the undercut are much exaggerated in order to more clearly show the construction and that in the drawings the original half'tone surface a of the plate, extending continuously over the fiat and beveled margin of the plate, is, in fact, composed of numerous fine dots formed by the fine crossing-lines of the screen; but these dots are so very fine in light or delicate half-tone plates, wherein my invention is chiefly used, that I have not attempted to show the dots in the drawings at Fig. 1, where they should appear.

I claim- 1. The improvement in the art of forming vignette-finished edges on half-tone metal plates, consisting in first cutting away the margin of the plate to form a square shoulder around the edge or margin of the plate, and then undercutting the margin of the plate, and depressing the undercut margin, to give a beveled shape to the original half-tone upper surface of the edge of the plate, substantially as specified.

2. The improvement in the art of forming a vignette finish on the edge of half-tone plates, consisting in undercutting the edge of the plate, and depressing the undercut marginal portion, so that the beveled or curved margin retains its original half-tone upper surface, substantially as specified.

3. A half-tone plate having a vignette-finished edge which retains the half-tone of the original half-tone plate, substantially as specitool-such as illustrated in Figs. 5, 6, and 7- fied.

very rapidly by simply carrying the rotating tool around the square shoulder left by the routing-tool. The vignette finish may thus be made as quickly and as cheaply as the routing itself can be done, as illustrated in Fig. 2.

GEORGE \V. A. ABELMANN.

Witnesses:

EDMUND ADOOCK, H. M. MUNDAY.

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