US845138A - Process for producing printing-plates. - Google Patents

Description

'NTTED TATES PATENT @FFTGE.

EMANUEL SPTTZER, 0F

MUNICH, GERIVIANY, ASSIGNOR OF TWO-FOURTHS T O IVIRS. ALPHA O. GDLDSMITH, OF BERLIN, GERMi iNY, AND ONE-FOURTH TO SOPHIE 'SPITZER,OF MUNICH, GERMANY.

\ PRQGESS FQF? PRODUGENG Pl lNTlNGwPLATES.

$pecification of Letters Patent.

latented Feb. 26, i907.

Application filed July 7, 1902. Serial No. 114,682. (Specimenal To all when it may concern: I

Be it known that I, EMANUEn Srrrznn, kunstmaler, a citizen of the Empire c Austria, residing at Munich, Bavaria, Germany,

have invented certain new and useful Improvements in Processes for Producing Printing-Plates; 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. 7

My invention relates to the art of making printing-plates, and in particular to the manufacture of photomechanical printing plates or surfaces;

The object of this invention is to produce printing-plates by photomechanical methods directly from continuous photographic plates or films produced by light, X, 'or Becquerel or other rays-that is, without the use of' screens or otherartifi'cial stippling steps.

The characteristic feature of the invention eonsists in the fact that a photographic plate is directly that is, without the use of screens or other artificial-stippling steps copied onto the plate to be etched provided with a sensitive layer, the copy then subjected to the influence of an etching agent and the etching allowed to take place, the result being an etched plate with minute cavities and between them minute elevations or stipples massed so as to correspond to the different shade and light values of the original and representing the same in all its finest details in a most erfect manner.

The fol owing example illustrates what I consider a preferable manner of carrying out my invention. 1 coat a polished printinglz. in the manner well known with a coatmg of sensitive solution, such as chrome-glue or gelatin solution, as used in the art. it is important to dry this coating as uniform and as free from grain as possible. This may, for instance, be effected by rotation and simultaneous warming on a' centrifugal apparatus or the like. i then expose the plate directlythat is, without interposing a from five to fifteen minutes will generally be found sufficient. that the condition which the sensitive coating has obtained by its exposure to light, what we may call its graduated hardening, and with it its graduated ermeability to acids and corresponding etc ing capability in the details, is not impeded or destroyed by such manipulations as melting on it asphaltdust or the like or by enameling or other procedures liable to destroy the above-mentioned properties of the coating after its exposure to light. The plate to be etched, with the copy obtained thereon, is then immersed into the etching-bath and the etch- ,ing allowed to take place until the whole' picture appears etcheoheven in the finest details. The strength or concentration of the etching-bath is that usually employed in j etching processes of this character, and where a bath of chlorid of iron, (FeCl which gives good results with a plate pre pared as above, is employed the stren th of the same varies between 30 an .Baum. According to the nature of the subject and of the detail and shading thereof, several etching-baths of different degrees of concentration may be employed, as will be understood by those skilled in the art. The temperature of the etching agent and the selection of the same are matters which are governed largely by the various conditions of the work and are matters of detail which, as well as in general all the different manipulations, procedures, and materials used in this process, those skilled in the art will readily select.

I find that it is better during the etching process not to brush away or shake .out the deposits formed by the etching agent on the plate, as they form the best protection against any injury of the finest parts in the further etching process.

By keeping the sensitized coating in its condition of graduated hardening, and thereby graduated permeability to acids; as before mentioned, a correspondingly-graduated etching takes place, the various points or stipples in consequence of a partial etching oil of their tops lying in different levels, so that in printing the taking of and giving off the printing-ink will be graduatedly stronger lin the intag lio (plateprinting) process or Care should now be taken v and the like.

etching off of the graduatedly fainter in the relief-printing process. I

After the etching operation is completed as above the plate is removed from the etching-bath and cleaned in the usual -manner and is then ready for printing. The partial printing elements before mentioned so characteristic for the resent process may be kept, according to t 1e puroses in view, stronger or lighter or even so elicate as not to be seen by the naked eye and only under the microscope, and yet it will be effective in )rintin The plates etched according to this method may be used for the typographical printingpress relief-printing as well as for plate-printing, intaglio. For plate-printing purposes of course a diapositive has to be employed instead of a negative, as used for the reliefprintin process.

The irect copy of the photographic plate or film onto the plate to be etched in connection with the above-described manner of directly etchin insures the highcstperfection of the reproduction in the various kinds of printing and at the same time renders the reproduction considerably cheaper and more easy to make.

Obviously this process may be employed also for ornamenting surfaces and plates of metal or other material and for making signs inta lio plates hereinbefore To not of the present in- The relief and described as the vention are not are separately covered in my concurrent ap plications, Serial No. 232,761, (No. 5,) and Serial No. 232,762, (No. 6,) filed November 14, 1904.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. In the art of producing photomechanical printing-plates, the process which consists in exposing a plate provided with a sensitized film under an ordinary continuous negative or diapositive and without the inagent without the application of any etching resist to the sensitiz coating.

3. Inthe art of producing photomechan ical printing-plates,. the process which consists in exposing plate provided with an or dinary sensitized coatin under an ordinary continuous negative or iapositive and without the interposition of a screen, etching said plate, and leaving the deposits, formed by.

the etching action, on the plateuntilthe end of the etching operation.

4. In the art of producing photomechanical printir'ig-plates, the process which consists in exposing a plate provided with a smooth ungrained sensitized coating under an ordinary continuous negative or diapositive and without the interposition of a screen, etching said, plate and leaving the deposit from'the etching agent on the plate.

5. The process of producing photomechanical printing-plates, which consists in exposing a plate coated with a layer of bichromatized gelatin under an ordinary continuous negative without the interposition of a screen, then immersing such plate into an,

etching-bath without the prior ap, lication of any etching resist and leaving t e deposits from. the etching bath on the plate.

In testimony whereof I aflix my signature in presence of two witnesses.

EMANUEL SPITZER. Witnessesz' HENRY R. MoGINNIs. CLARA. I. PARKER.