US1898798A - Art of photo-engraving - Google Patents

Description

Feb. 21, 1933. R H, W E 1,898,798

ART OF PHOTO-ENGRAVING Filed March 22, 1952 ZSrmentor PQLLZEWT'IZGVZ (lttorneg Patented Feb. 21, 1933 UNITED s'rairss PATENT OFFICE PAUL H. W. WERNER, OF WELLESLEY, MASSACHUSETTS ART OF PHOTO-ENGRAVING Application filed March 22, 1932. Serial No. 600,573.

for the Ben Day process.

An important field of utility for the Ben Day process is on line cuts whereon portions of the same are to be stippled, screened or shaded. These line cuts come to the Ben Day department as a print on metal, usually a zinc plate, and it is the province of the Ben Day operator to prepare this metal print preparatory to laying the desired tint thereon.

Since, in line out work, the tint is to be laid on only certain or predetermined portions of the plate, those areas whlch are not to be tinted must be stopped out or pro-,

tected. This protecting operation has heretofore been done by a step called gamboging, or gumming out. By this method the Ben Day operator heretofore has been required to paint the background which is to be protected, with gamboge, leaving plain or untreated the subject or surface to be treated. This has meant that the operator must paint up to and around the subject or surface to be tinted, and in the vast majority of instances this step requires the services of a skilled operator or artist, consumes considerable time and labor, and necessarily adds to the expense of this type of work.

After the background has been gamboged, the tinting film, properly inked, islaid on the metal print and the tint transferred to the metal print by rubbing with a stylus, roller, or the like. Thereupon the film is removed from the plate, the inked impression thereof remaining on the exposed metal, on those parts, subjects or surfaces which are to be tinted in the completed picture, and necessarily over at least a portion of the back ground. On washing the plate in warm water, the gamboge, being soluble in water, is removed, together with the excess tint thereon, leaving the tint only on those surfaces to be shaded, where it constitutes a resist in the etching.

The metal print is then dusted with a powder known as topping powder,'having an aflinity for the ink of the tint, which is then burned in preparatory to the etching operation,

It will thusbe understood and appreciated, from the foregoing, that heretofore it has been the background and other surfaces surrounding the surface or subject to be tinted which have been treated preparatory to the Ben Day process.

An important object of my present invention resides in the fact that I treat, pri-' marily, the surface to be tinted, and only incidentally treat the background and other surfaces not to be treated by the Ben Day process.

In carrying out my present novel process I have discovered that by painting the surface to be ultimately tinted, rather than the sirflaces surrounding said surface to be tinte a but a fraction of the time heretofore required, resulting in asaving in time, labor, and money, ing the work of the Ben Day operators.

My novel process is illustrated conventionally in the accompanying drawing, wherein Figures 1 to 5 indicate the successive steps of the process.

In practicing my novel process, I paint the surface of the plate 10 to be tinted with a solution 11 susceptible to substantially instantaneous removal by a solvent, such as gasolene, benzol, or the like. This is illustrated in Figure 1 of-the drawing. I find that a solution having as a base lithographic tusche, constitutes a satisfactory primary coating for this purpose,

since it is quick drying and readily removable by a solvent,

am enabled to produce better results in in addition to greatly simplifytusche being well known in the art as being of the same nature as lithographic drawing or painting material and one variant thereof being made by melting together wax, 2 parts; mutton tallow, 2 parts; soap, 6 parts; shellac, 3 parts; and lampblack, 1 part. 7

As soon as the coating 11 on the surface to be tinted has dried, which is a matter of but a few moments, I then subject the entire print, {both background and the already coated portion to the treatment with a secondary solution '12, not readily removable from the metal plate by a solvent except where such second coating overlays the primary coat. This is illustrated in Figure 2 of the drawin 5 The application of the secondary coat may be accomplished by simply soaking a. swab, such as cotton batting, with a suit-able solution, and wiping the same across the surface of the metal print, requiring but an instants time for this step. This secondary coat is dried, and l-then subject the print to a swabbing operation with a swab soaked with a suitable solvent, such as gasolene. The action of said solvent, during said swabbing, will remove both the primary and sec ondary'coats 11 and 12' from those surfaces which are to be tinted, as illustrated in Figure 3 of the drawing, but wlll not normally IQIDOXG the second COFti'r'flOlll llllOSQ SHITZICES QZWhlCll were not first treated with the primary coat. I find that a satisfactory solution for the secondary coat may be made by dissolving and thoroughly mixing in one and one-half pints of water one commercial stick of licorice, fifteen to twenty drops of glycerine, and one tablespoon full of lralsomine, the licorice constituting the base of the solution, the glycerine functioning to cause the solution to adhere to the plate, and the 3;kalsomine affording the desired opaque coloring matter. It will be understood and appreciated, of course, that in both the primary and secondary solutions I am not limited to the particular ingredients mentioned,

,these being simply for illustrative purposes,

and the only requirements for these coatings being that the primary coat should be readily removable by a solvent, and the secondary coat shall not be readily removable by sol- 4Q ;vent except where it is laid on the primary coat,:b.ut shall be readily removable by warm water, for example.

As soon as the metal print is again dry, the Ben'D-ay film 13 is applied and the tint thereof transferred to the metal print, as

illustrated by the stippling in Figure 4 of the drawing. The plate is then washed in warm water, which will dissolve and remove the secondary coating 12 and the excess tint fiotnarried thereby, as illustrated in Figure 5.

There'upon the print is dusted in the usual manner with a topping powder, said topping powder is burned in, and the plate is then etched.

A subject or picture which has been treated according to my invention has clean-cut outlines and other beneficial aspects of appearance not ordinarily capable of accomplishment by the prior gamboging method,

I11I1Cl these results areachieved in but a fraction of the time required for the proper carrying out of the said gamboge method. By my novel method-the field of utility of the Ben Day method of photo-engraving is -iconsiderably broadened in scope, enabling the Ben Day method to be utilized in subjects heretofore considered unfeasible because of the time, labor and expense of preparing such subjects for tintin I believe that the steps herein described in preparing metal prints for the reception of the Ben Day tints are novel, and have therefore claimed said steps broadly iii this ap plicatlon.

My invention is further described and defined in the form of the claimas follows:

The method of preparing tinted lithographic prints which comprises applying to the portion of the surface to be tinted a coating which is readily removable with a solvent, then applying to the other portions of the surface and also to at least the marginal portions of the'first applied coating a coating which by a solvent is readily removable with the first applied coating where it overlies the same but which is not readily removable by the solvent from the print

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