Screen for making photomechanical printing-plates
US 498127 A
Description (OCR text may contain errors)
M. LEVY. SCREEN FOR MAKING'PH-OTOMBOHANIGAL. PRINTING PLATES. No. 498,127. Patented May 23,1893.
1m: NYORRIS PEYERS cm. PHOTO-LUNG" WASHINGTON: n. c.
UNITED STATES PATENT OFFICE. 7
MAX LEVY, OF PHILADELPHIA, PENNSYLVANIA.
SCREEN-FOR MAKING PHOTOIV IECHANICAL PRINTING-PLATES.
SPEOIFIGATIONforming part of Letters Patent No. 498,127, dated May 23, 1893;
Application filed December 22,1892. Serial No. 456,065- (No model.)
To all whom it may concern.-
Be it known that I, MAX LEVY, a citizen of the United States of America, residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented certain new and useful Improvements in Gratings or Screens for Photographic Purposes; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to letters of reference marked thereon, which form a part of this specification.
This invention relates to improvements in gratings for the production of pictures for illustrations by the half-tone process; and it consists in providing the usual grating, having parallel lines or cross-lines, with subsidiary lines or dots located between the spaces formed by the cross-lines.
In the production of half-tone engravings by means of a screen or grating it has been customary to employa screen or grating having parallel lines or cross-lines, and the effect obtained by the use of such a screen is open to several objections, among which may be noted that the series of lines and dots which result therefrom give the appearance of a network over the resulting picture, and it is immaterial how fine the rulingmay be there are always some details that are lost by reason of the fact that the lines forming the picture have no reference whatever to the design, and consequently many details occupying the space of but one or even three spaces or intervalsilose their definition and are often eliminated in the resulting picture, the lines filling or corresponding withtheseparated parts of the object, While the aim is to reproduce as closely as possible the characteristics of the original in its minutest as well as its broader details, which is not always possible with the cross-line screen, and to accomplish such end I desire to retain the advantages of the ruled screen and provide such a screen as will render the details more accurate than can be accomplished by simple lines or cross-lines, and to this end I produce a screen having the interstices between the ruled lines being partially filled or occupied by dots, or with sinuous or crooked lines, as will be hereinafter fully set forth andspecifically pointed outin the claims.
In the accompanying drawings: Figures 1 and 2 are-enlarged plan views of gratings or screens as they appear when made in accordance with my invention, and Fig. 3 is an enlarged sectional view.
The gratings or screens maybe made up in the usual manner; that is to say, either by photography, manual or mechanical manipulation to produce on t or in the glass plate straight lines which are parallel with each other or crossed, the interstices being occupied either by sinuous lines, crooked lines or dots which willgive a stipple effect.
. In the accompanying drawings A designates the plate of glass, which is provided with straight lines a, which may be parallel and cross each other as shown. stance the spaces between the straight lines are occupied by sinuated crooked lines, or by dots which are granular in form or similar to what appears in marks made by a crayon, when highly magnified. In each instance the interstices are rendered partially opaque, in any suitable manner, preferably the same means being employed that are used to render the lines opaque. The lines or obstructions located in the interstices may be formed after the manner set up in PatentNo. 492,333, which was issued February 21, 1893, to Louis E. Levy and Max Levy, or they may be formed by photography, the lines being reproduced from a suitable pattern upon the glass plate,
which becomes a screen. In use such a plate will give a result which differs from the result given by straight or curved lines; and with such a plate as described a softer appearance is given to the picture and the different shades of light better and more effect- .ively brought out, and it will be obvious that In either in- IOC 1. In a grating or screen for the purpose set forth, having opaque lines, the interstices or spaces between said opaque lines being rendered partially opaque.
2. A grating or screen for the purpose set forth, consisting of a plate having opaque lines which are parallel with each other and are crossed by asimilar series of lines, the in terstices being partially filled or occupied by finer lines.
3. A grating or screen for the purpose set forth, consisting of a plate having opaque,