US996959A - Method of making ready printing-plates. - Google Patents

Description

WIT/v 555s I 1' s. WEINWURM. METHOD OF MAKING READY PRINTING PLATES.

APPLICATION FILED AUG. 7, 1901 996,959, Patented July 4, 1911,

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METHOD or Max ne READY remains-nuns.

eec es.

Specification of Letters Patent.

Application filed August 7, 1901. Serial No. 71,263;

To all whom it may concern:

Be it known that I, STEPHAN WEINWURM, a citizen of the Kingdom of Hungary, residing at Stuttgart, in the Kingdom of Wiirtemberg, Germany, have invented certain new and useful Improvements in Methods of Making Ready Printing-Plates, of which the followin is a description, reference-being had to 51c accompanying drawing and to the letters and figures of reference marked thereon. v

This invention has for its object a chemicographic method of preparing printing plates, whereby when printing with the plates the usual packing or make-ready is rendered unnecessary.

The process may be carried out in two ways:

The first method is as follows: A negative of the object or picture which is to be used for the printing side of the plate is taken by means of a prism orreversing mirror, and

another negative is taken of the same size but without the reversing device, in such a way that the two negatives are opposed right and-left. So-called register marks or the like are made on the edge of the original object or picture before the negatives are -made. Each impression or image is now transferred to the same metal plate by any suitable copying process, one impression (the reverse picture) being applied to the face and the other to the back of the plate so that the pictures register, this result being obtained by laying the register marks over one another the marks having been placed on the edge of the plate after the first transfer. In-order to obtain an exact register the negatives must, as before stated, he opposed right and left. Thenthat transfer or image which corresponds in printing to the direc: tion of the original is etched or, if the picture when printed is to appear reversed, the.

other transfer or ima e is etched; the other or second transfer is t en etched on the back of the plate but-is made-more effective in graduations of light and shade which will in eachcase be suited to the character of the original picture. In autotypes for instance the lights of the image on the back of the plate may be etched out entirel while the shadows are. left unaffected. T e intermediate tones are graded according to the capability of the graining to resist more or process is as follows: The same negative is transferred on to both sides of the metal plate but the negative to be transferred or used in transferring to the back of the plate must be stripped and transferred directly while that for the front of the metal plate must be stripped from the glass plate and turned over and remounted or applied reversely in order that a registering of both copies on the metal late be obtained. The

etching then takes p ace in the manner previously described only on the etching in the rear side the strong places must be covered in order that they may not be attacked by the etching fluid.

In both processes the metal plate is thinner at the places where the lights are etchedout than at those places where the shadows remain, that is to say, at those places which were etched sli htly or not at all. The thicker places of the plate then rint more strongly and the thinner more lightly and the desired effect is obtained. without the finished block requiring any packing. It

will thus be observed that I employ familiarsteps of an art as the initial steps of my new process and that the manner in which my process is a plied produces a printing plate having ho lows or depressions in its back which correspond to the high-lights and intermediate tones of the picture or delineation on the face of the p brief, a plate in which make-ready has been put into the back of the plate.

. It is, for example, well-known in the art, especially in that branch of the art having to do with half-tone plates, that either a prism or a reversing mirror may be used to produce a reverse negative, and that such a negative is commonly employed in printing 0F JERSEY CITY, NEW JERSEY, A

Patented July 4, 1911. i

ate, or in or transferring the image upon or to the face of a pre ared'metal plate. It is also wellknown t at instead of using a prism or reversing mirror a reverse negative may be obtained by stripping the film from the glass plate of the negative, turning it over and process to produce a new result.

While any copying or transferring process may be used to get the opposing images on opposite sides of a plate, I have shown that my process is especially adaptable in employing the familiar photographic methods in which a print is madeupon a previously prepared metal plate by the action of light through a negative and, as is briefly said in the art, this print is then etched. In my process I, preferably, do the same thing to the back of the plate'that'has been previously done to the front of the plate. Obviously, if desired, one method may be employed in getting the image on the face of the plate and another method may be employed in getting the image on the back of the plate, but it will, of course, be generally expedient to use the same method in each case, varying only to get the ordinary negative for one face and a reverse negative for the other face, so that the images may be properly opposed and registered. Then, as described, when the image is transferred by anysuitable process tothe back of the plate I etch the back of the plate and etch portions. of the back of the plate to successively greater depthsvuntil the hollows or depressions conform to the light and intermediate tones in the face of the plate, the depth of each depression bearing a due relation to the grade of-the corresponding tone of the subject on the, face of the plate.

I have not detailed the etching steps because the methods of etching successively or in different. degrees on different parts of a plate are well understood in the art, as in fine etching or staging. I, however, carry forward the etching with a new purpose and produce a plate varying'in thickness in accordance with the tones of the subject.

- A simple illustration of the preferred manner in which my methods are practiced is presented in the accompanying drawing in which,

Figure 1 is a plan of an original of which a photograph is to be taken and which is to be reproduced by a printing plan view of a reverse plate. Fig. 2 is a negative of the origlnal. Fig. 3 is a plan view of a negative of the origlnal. Fig. 4 is a plan view .showing an impression made by printing from a reverse negative in the usual manner upon the face of a metal printing plate. A copy or reproduction printed by the plate would have an image or impression having the same direction as the original of Fig. 1. Fig. 5. is a plan view of an impression similarly rinted or photographed upon the back of the plate by the customary method. Fig. 6 is a section of the rinting plate with the impressions on the front and back, the illustration of the impression being arbitrary and designed thus to better indicate the different tones. Fig. 7 is a view showing the effect of etching the back of the plate to successively greater depths in accordance with the tones of the impression previously printed upon the back of the plate, the illustration being somewhat modified to bring out the relative degrees of thetones. Fig. 8 represents a late with a stripped negative film on the ack of the plate and a stripped reverse ne ative film on the face of the plate, in accor aneewith the second'described method of first producing the plate of Fig. 6 and then the plate of Fig. 7.

It will be observed that in this illustra the high-light. At two corners are register marks placed on the original so that they may be reproduced on the negatives. It will be understood that the various proportions are either diminished or exaggerated as expedient with reference to'a clearer illustration of the steps of the method.

In Figs. 2 and 3a reverse negative and a negative are respectivel upon glass plates. In igs. 4 and 5 these negatives have been respectively applied to the face and the back of the plate as indicated, the ic tures there showing oppositely. Both the ace and the back of the plate at this time are level and differ in no respect from the ordinary half-tone plate, except that there is on the back of the plate an impression of a picture reversely arranged with reference to-that on the face of the plate. On the back and face of Fig. 6 and on the face on Fig. 7, the light dots indicate the high-1i ht, the heavier dots the intermediate or hal -tone and the short solid line the shadow or dark. When, however, the next step of successive etching is performed the new result appears as evldenced on the back .-of" Fig. 7 where the plate, as before described, is of different thickness in different parts, or in other words has a graduated back, thinnest at the high-light, thickest at the dark or shadow, and intermediate at the intermediate tone.

Fig. 8 illustrates the familiar a plication 'of a reversed negative film to the ace of the plate for the purpose of printing an impresshown imposed sion through the negative and also illustrates the ap lication of a stripped negative film taken directly from the glass and applied Without reversing to the back of the plate so that a picture may be printed through this negativeidentical with the picture on the face of the plate but 0 positely arranged.

It will be understoo that if looking through a plate with the negatives applied or the impression produced on the face and 2 That improvement 1n the art of pre-' paring printing plates which consists in photographing a plcture or delineation upon the face of a plate and also photographing upon the back of the plate a similar lcture reversely arranged with reference to t e picture on the face of the plate.

3. That improvement in the art of treating printing plates which consists in photo graphing a picture or delineation upon the face of av plate, and also photographing a similar reversely arranged picture or delineation upon the back of the plate, and in then etching both sides of the plate. 4. That improvement in the art of treating printing plates which consists in photographing a picture or delineation upon the face of a plate, and also 'hotographing'a similar reversely arranged picture or delineation upon theback of the plate and in then etching both sides of the plate, and in then further etching the back of the plate' to form graduations in its back.

5. That improvement in the art of making ready printing plates which consists in etching upon the' back of the plate in a graduuated manner a reversely arranged image of the picture to be printed.

6. That improvement in the art of mak ing ready printing plates which consists in producing on the back of a plate areversely arranged fac-simile of the picture or delineation upon the face of the plate and in then etching the back of the plate to successively greater depths from the dark to the hig lights.

7. That improvement in the art of making .ready original printing plates which consists in producing a negative from the subject to be illustrated and transferrin it to the back of a plate, and then producing a reverse negative and transferring it to the face of the plate and in register with the picture or delineation at the back of "the plate.

8. That improvement. in the art of making ready orlgina'l printing plates which consists in producing a negative from the sub'ect to be illustrated and transferring the subject by it to the back of the plate, then producing a reverse negative and transferring the subject by it to the face of the plate and in register with the picture or delineation at the back of the plate, and in subsequently producing graduations in the back of the plate by etchingto varying depths.

9. The process of preparing printing plates, whlch consists in transferring an image to both the face and'the back of a plate and etching the image upon the face to produce a printing surface and upon the back to produce graduations of level in various tonesof .the subject.

10. The process of preparing printing .plates which consists in making a direct negative anda reverse negative o a subject, printing from one negative on the face of a metal plate and from the other'on' the back of the plate,-etching the print on the face of the late to produce a printing surface and etc ing the tones of t e. print on the back of the plate to different depths.

11. A plate provided on each side with an image of the subject to be illustrated, the images being oppositely arranged and in the register, and theimage on the back of the plate being etched away at the lighter portions of the picture.

In testimony whereof afiix my slgna ture, in presence of two w1tnesses.

STEPHAN WEINWURM.

Witnesses:

WALTER SGHWAEBSCH J LIUs Harm.

Images