US1434798A - Process of making nickel-plated halftone plates - Google Patents

Description

E. E- STAFFORD.

PROGESS OF MAKING NICKEL PLATED HALFTONE PLATES.

APPLICATION FILED JAN. 16., 1922.

1,%3%,79& Pautented Nov. 7, 1922:.

FIE

INVENTOR. 54 2 E. jm'f w A TTORNEYQS of the plate EHCE.

L E. STAFE'UBD, 01E INDIANAPOLIS, INDIANA.

- l-- NICKEL-PLATED HALFTONE PLATES.

Application filed. January 16, 1922 Serial No. 529,534.

To all whom it may concern:

Be it known that I, EARL E. S'rArroro, a citizen of the United States, and a resident of Indianapolis, county of Marion, and State of Indiana, have invented a certain new and useful Process of Making Nickel- Plated Halftone Plates; and I do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanyin drawings, in which like numerals refer to like parts.

The object of this invention is the nickel plating of copper half tone plates so that they will be superior to cop or half tone lates in the quality and per action of the alf tones rinted or produced, and much more durable than the copper plate.

Half tone copper plates have been made and used in the art for about thirty years and to a very great extent, because of the fine quality of the work produced by them. As is well known the surface of said half tone plates consists of a vast number of points which stand in relief, and hollows which vary in size and depth. When the late is inked just previous to. taking an impression of it, the ink is distributed uniformly over the points and the difference between the heavy color in the blacks and the light tones in the highlights is due to the sizes of the points and the open spaces between the points. 7

In making the half tone copper plate, the polished surface of the co per is sensitized and a print made on this rom the negative. The print when baked or hardened forms an enamel which acts as a resistance to the acid used in etching. The metal surfaces which are not covered by the lines and dots in print are left exposed to be eaten down by the acid, the parts being covered by the print beiu left in relief after the plate is etched. he character of half tone copper plates and the method of making the same is very familiar to those skilled in the art and no further explanation of the details thereof it is believed need be made.

In use a half tone copper plate very quickly becomes worn and dulled and the pictures printed therefrom indistinct and blurred. This is due to the softness of the copper metal which forms the plate. Another disadvantage of the copper plate is that it does not well release the ink in printing and, therefore, does not make as clear an impression as it would doif all the ink were released by the copper plate. A further disadvantage is that the ink has a disastrous effect-on the copper. The acids of the mk make the copper corrode and it will assume a different color after a few hundred lmpressions. The net result is that with the copper (plates only a relatively small number of goo impressions can be made.

It has long been desired to improve the wear and durability and other characteristics of half tone plates, but no satisfactory process has, prior to the present one, been developed for accomplishing that result. Efi'ort has been made to overcome this difiiculty by making electrotypes or nickel plates from the original half tones. When the original half tone copper plate is nickel plated, the nickel fills the hollows in the middle tones and blurs the same so that it prints practically black if sufficiently nickel plated and thus makes the prints or impressions quite unsatisfactory,

The chief feature of this invention consists in the process of over-etching the half tone cop er plates to a sufiicient extent to offset the t ickness of the deposit of the nickel, when the same is nickel plated, so that the nickel plated half tone would have the same character of surface as the copper half tone excepting that the surface would be nickel instead of copper.

It may bev preferred by some, and in some instances, to remove the enamel before the over-etching is accomplished. By overetching herein is meant etching beyond what would be done if the plate were not to be nickel plated, and to a sufficient extent to offset the thickness of the deposit of the nickel when it is nickel plated. This can be done either with or without the removal of the enamel. By enamel is meant and material on the plate that resists the am The full nature of the invention will be understood from the accompanying drawings and the following description and claims:

In the drawings, Fig. 1 is. a diagrammatic view of an original copper half tone plate insection, parts broken away and parts on agger'ated. Fig. 2 is the same with said original copper plate nickel plated as anything else would be nickel ated. Fig. 3 is the same as Fig. 1 over-etc ed, that is,the surfaces ofthe hollows are etched to greater Mil extent and depth than in Fig. 1. Fi 4 is the same as F1 3 with the over-etche copper plate nicke plated. v

In carryin out the process herein, as stated hereto ore, the first step is to make an original half tone copper plate by the process heretofore employed in this art and so that it will make good im. ressions or pictures, bringin out the mid le tones as well as the sha ing and the high lights. In the diagram shown in Fi 1, one portion of the plate is coarsel etc ed, the middle portion is medium an the ri ht-h'and portion is finely etched. This illustration is given merely for the purpose of explanation, as in half tones the different kinds of surfaces are distributed irregularly over the plate instead of as here shown. As shown 1n Fig. 2, if this original co per plate in Fig.1 is merely nickel plate it will blur the middle tones or surfaces of the plate that is, fill the small hollows with nicke and partially fill the other hollows so as to change the character of. the plate and particularly the impression or 'print which it will produce.

The second. step in this new process consists in over-etch1ng the original copper half tone plate, after being completely finished, such as shown in Fig. 1. The over-etching is referably accomplished by subjecting said original plate to a longer etching process, by leaving said plate in the etching solution longer, say ten or fifteen seconds longer, than if one would make in the usual way a half tone copper plate. The length of this additional period in the etching, in

order to over-etch the plate, varies slightly accordin to the fineness of the screen, but

those skilled in the art understand fully the effect of the fineness of the screen upon the length of time required for the etching solution to accomplish its Work and, therefore, there is no difliculty in workmen skilled in this art in determinin how much longer any particular copper half tone plate should be left in the etching solution in order to over-etch it for the purpose herein set forth. Such over-etched plate is illustrated in Fig. 3, which differs from Fig. 1 only! in the .de th of the hollows or recesses andlateral thmness of the points or. projections in the metal plate.

The third ste' in this process consists in nickel lating t e over-etched copper half tone p ate by employing the usual nickel plating process so as' to ut the proper deposit of nickel on the sur aces, both the holows and the points or projections, which will bring the dimensions of those. parts back to exactly the same condition as in the original copper late, as shown in Fig. 1.

' In other words, t e over-etched copper plate is left in the nickel plating solution from fifteen to'twenty minutes, according to the much harder, more lasting and duare ve rable than those of the copper plate and would stand five or more times the use in printing half tones than the copper plate would, and yet the cost of making the nickel plated half tone plate would not be more than five or ten per cent greater than the cost of the original copper half tone plate. Furthermore, the nickel surface releases the ink much better than the copper surface as it releases all of the ink and, therefore, makes a clearer im ression or print than the copper surface. 150 the acid in .the ink does not injuriously affect the nickel surfaces or corrode them, nor does the nickel have any efiect on colored inks, as delicate colors, such as yellow, pink and light blue, may be used and after several thousand impressions, the ink will be the same color as 111 the beginning of the operation, whereas with copper it would turn much darker. Therefore, the nickel plated half tone plate not only wears much longer and is more durable and is capable of producing more impressions, but it also produces much better impressions and prints .and it is articularly important and advantageousin colored printing.

As stated before, the over-etching may be v plate, and then nickel plating the same.

2. The process of making nickel platedhalf tone plates, which process includes over-etching a copper'plate, and then nickel plating the same with a deposit of nickel thereon, substantially equal to said overetc-hing.

3. The process of making nickel plated half tone plates, which process includes over-etching a copper plate by leaving the same in the etching solution for ap roximately longer than if a copper hal tone plate were to be ultimately made, the length of time depending upon the fineness of the screen use in making the picture to be plated, and then nickel plating the same by placing it in a nickel plating solution long enough to make a deposit of nickel equal to the over-etching-according to the fineness of the screen used in making the picture for the plate and the voltage used in the nickel plating.

at. The process of making nickel plated half tone plates, which process includes placing a copper plate in an etching solution and over-etching it by leaving it in said solution for approximately fifteen seconds longer than if the plate were not to be nickel plated, and then nickel plating the same by placing it in a nickel plate solution for approximately twenty minutes, substantially as and for the purpose set forth herein.

5. The process of making nickel plated half tone plates, which process includes as its essentially novel step over-etohing a previously enameled and etched copper half tone plate after having removed the enamel so that the deposit of nickel thereon when nickel plated will leave the points and hollows of the surfaces of the metal plate the same as in the original copper plate.

6. flhe process of making a nickel plated half tone plate, which process includes enameling and etching a copper plate, removing the enamel, over-etching the copper half tone plate to an extent equal to the desired thickness of the proposed nickel plate, and then nickel plating the same.

7. The process of making nickel plated half tone plates, which process includes enameling and etching a copper plate, removing the enamel, over-etching the copper half tone plate, and then nickel plating the same with a deposit of nickel thereon substantially equal to said over-etching.

8. lhe process of making nickel plated half tone plates, which process includes 9. The process of making nickel plated half tone plates, which process includes enameling and etching a copper plate, removing the enamel, over-etching the copper half tone plate by leaving the same in the etching solution for approximately longer than if a copper half tone plate were to be ultimately made, the length of time depending upon the fineness of the screen used in making the picture for the plate, and then nickel plating the same by placing it in a nickel plating solution long enough to make a deposit of nickel equal to the over-etching according to the fineness of the screen used in making the picture for the plate and the voltage used in the nickel plating.

10. The process of making nickel plated half tone plates, which process includes enameling and etching a copper plate, removingthe enamel, placing a copper half tone plate in an etching solution and ox'eretching it by leaving it in said solution for approximately fifteen seconds longer than if the plate were notto be nickel plated, and then nickel plating the same by placing it in a nickel plating solution for approximately twenty minutes, substantially as and for the purpose set forth herein.

In witness whereof, I have hereunto afiixed my signature.

EARL E. STAFFORD.

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