US1659949A - Engraving process - Google Patents

Description

Feb. 21, 1928.

R. N. GETCHES ENGRAVING PROCESS Filed Jan. 8. 1924 gnou/woz Wd@ s Patented Feb. 21,1928.

UNITED STATES 1,659,949 PATENT OFFICE.

RAYMOND N. GETCHES, QF GLEN RIDGE," NEW JERSSEY..

ENGRAVING PROCESS.

Application led A.'I'axmary 8, 1924. Serial. No. 685,056.

My invention relates particularly to engraving of metallic orother plates or cylinders for use in mechanical prlnting, and is especially adapted for use in connection with engraving of copper cylinders or flat plates for use in rotary or flat bed printing presses, whereby photogravure prints may be c conomically and quickly produced. My improved process is also applicable to the production of line prints where half tones or medium lights or shadows are not present. It is particularly applicable to the re roduction of toned pictures and photograp s having innumerable variations of light and shade or to the reproduction of a composite consisting of combined pictorial and printed matter where both line and 'type Work are to be reproduced with a photograph or other pictorial print.

Heretofore, in carrying out the so-called rotogravure process, -the Jilollowmg mam steps have been considered necessary. First, a negative photograph is made on celluloid or glass from pictures and printed matter to be reproduced, it being necessary to separately photograph the pictures and the line Work or printed matter andpassemble the same by pasting or otherwise attaching to the Celluloid or glass backing; second, from this composite negative a positive photographic print is made on transparent material, such as Celluloid or glass; third, the positive so made is printed on the so-called carbon tissue which is a gelatine coated paper sensitized with potassium bichromate, or other similar sensitizing material. This printing is done by exposure of the carbon tissue to light, through the usual ruled screen and then through the composite positive. This last printing operatipn is known as the carbon printing process. Fourth, the exposed carbon tissue is applied when wet,

under a rolling or rubbing pressure, called squeegeeing to the surface of a copper cylinder so that the gelatine adheres thereto, after which the paper backing is removed by treatment with hot water which also dissolves tlie soluble portions of the gelatine, leaving the insoluble bichromated gelatine on the cylinder, and the impressions thus transferred are then etched on the cylinder. Fifth, the type or line work is firstletched by the use of the usual ferrie chloride after covering the halt` tone portions with asphaltum. The etched portions 'are then Washed and dried and the asphaltum re I moved from the half tone or picture portions. Sixth, the previously etched type or line Work is then covered with asphaltum and the tone pictures etched in a similar manner but With particular attention to the quality of the `high lights and shadows, or the process is sometimes reversed and the toned pictures etched first vand the line or type work last. Seventh, the asphaltum-last applied is then removed and the cylinder thoroughly cleaned. It is then ready for the printing operation.'

From the following description of my improved process, read with reference to the accompanying drawings, it will be noted that a number of the steps in the previous process of producing the engraved cylinder or Vplate are unnecessary and are eliminated with a consequent saving of time, labor, material and expense.

In the accompanying drawings Fig. 1 indicates the various surfaces produced in the successive steps of one form of my improved process when used in the production of a composite line and halftone gravure print; Fig. 2 indicates the successive steps when the screening is introduced at another pointv in the process; and Fig. 3 indicates the successive steps when the screening is produced only on the plate or cylinder to be engraved.

My improved process may be described as follows: First, the pictorial print or picture (a) submitted for reproduction is photographed as a negative impression (b) on a photographic film having a paper, Celluloid or other suitable backing, either opaque or transparent, in reduced or enlarged size, ac-

cording to the final reproduction required. I prefer to use for this purpose the well known bromide paper. The type or line matter (c) is also photographed on similar paper, (d) or other material, but preferably having a quality of sensitiveness adapted to give much greater contrast than thaty used rfor the picturesv having many intermediate with the negative impression made thereon. The screening may also be otherwise produced as hereafter described.

The line and printed portions and the pictorial portions are then assembled as a composite negative print (f) on the same backing. Second, this composite negative print is then squeegeed face to face with a sheet of f gelatinized and sensitized paper (g) known as carbon tissue similar to that used in the previous process above referred to, the bromide negative being Wet with water and the carbon tissue wet with the sensitizing solution when squeegeed together. The sensitizing is accomplished by immersing the carbon tissue for about three minutes in a solution of bichromate of potash-one ounce, potissium-ferricyanide-one ounce, potassium bromide-one ounce, and water-eighty ounces, and after draining for a fraction of a minute, immersing in a solutionv comprising glacial acetic acid-one quarter of an ounce, ydrochloric acid-one quarter of an ounce, formaldehyde (40%)-tive and one half ounces, and water-one hundred and ninety ounces. If the screen lines have not been produced previously on the composite negative print as above described, the carbon tissue (i) may have the screen lines printed thereon, after being sensitized with a three per cent potassium bichromate solution, by being exposed to light through the white line screen (e) which produces the insoluble gelatine lines on the carbon tissue. It is then dried and again sensitized as previously described before the composite print isl squeegeed thereon. It is obvious that these operations of printing the screen lines and the picture respectively on the carbon tissue may be reversed. Third, the carbon tissue after being in contact with the bromide or similar print for fifteen minutes or more, ac-

cording to quality or depth of tone desired,

is stripped away from said bromide or simil lar negative leaving the carbon tissue (y) with the soluble and insoluble gelatine thereon which is placed in contact with a copper or metallic cylinder or a flat copper or metallic plate and the backing and the soluble portion of the gelatine removed with hot water as in the oldv recess. Fourth, the cylinder is then etched, (le, c) line work and half tone separately as in theold process or as an' entirety by the use of ferrie chloride without the necessity of separate etching of the .type or line matter and the pictorial matter, as required in the former rocess, since this process gives a thickness o gelatine and resist making it possible to obtainrequired results in one etching.

The c linder is then washed and is ready for making the print (VZ, Z), as is usual in the process of rotogravure printing.

As an alternative method of producing the screen lines on the cylinder or plate, apiece of sensitized carbon tissue (m) may be exposed to light through the screen' (e.) as above described, then transferred directl to the cylinder or plate. (n). .When the acking and the soluble gelatine are removed, the insoluble gelatine lines only remain on the surface of the cylinder or plate.

The composite negative print, (o) without screen lines, is then squeegeed onto another sheet of carbon-tissue (p) and the gelatine thereof transferred to the cylinder or plate (n), and su er-imposed on the previously applied inso uble screen lines. The insolub e` ortions of this layer of gelatine are then was ed away, after which the cylinder or plate (g) is ready for etching and printing (r as efore. 1,

n view of the above description, it will be apparent that' through the use of my process it becomes necessary only to make a single photographic bromide or other print of the matter to be reproduced, this being directly applied to the sensitized carbon tissue and the gelatine transferred therefrom to the cylinder which is immediately etched after removal of the paper backing. All photographic reproduction by exposure to light, except photographing for the first negative print and the formation of the halftone screen lines when the latter are formed separately, is thereby eliminated. The use of any trans arent sheet material is consequently avoi ed.

Having thus described my invention, I do not wishto be understood as being limited to the details of pxrocedure and the specific materials set fort for various changes may be made by those skilled in the art without departing from the spirit and scope of my invention.

What I claim and. Letters Patent is:

1. In theprocess of preparing a photogravure 4printing surface, the steps which comprise placing a negativeimage of the matter to be reproduced having'dark portions and high lights of different densities formed on a film containing chemical substances which are ada ted to produce corresponding. degrees of insolubility in a sensitized gelatinous or similar ilm, in direct contact with such a gelatinous iilm, separating said image from said gelatinous film for a predetermined period, transferring the latter to the surface to be etched, removing all soluble portionsof said gelatinous film, and etching said surface in the presence of its remaining insoluble portion.

2. In the process of preparing a photogravure printing surface which compr1se the following steps, placing a negative silver .bromide image of the matter to be re rononame and then transelatine to become insoluble,

to the surface tine to become inso uble, and then transferring said gelatinous film to the surface to be etched. y

4. In the process of producing a photogravure printin surface, in combination with the formation of tone-screen lines at a suitable point therein, the steps which comprise placing a negative formed on silver bromide paper, in mtimate contact with a sensitized gelatinous film whereby ortions of said negative cause correspon ing portions ofthe gelatine to become insoluble, ,Y

transferring said film to the surface to be etched, removing the soluble portions of the gelatine, and then etching said surface.

5. In the process of producing a photogravure printing surface, in vcombination with the formation of tone screen lines at a suitable point therein, the steps which ,com-- prise placing a negative formed on silver bromide paper of the matter to be reproduced, in intimate contact with a sensitized gelatinous film whereby darker, portions of4 said negative cause portions of the gelatine to become correspondingly insoluble, transferrin said film to the surface to be etched, removing the soluble portions of said hn, and then etching said surface.

6. In the process of producing a photogravure printing surface, the steps which comprise assembliner separate photographic paper negatives, matter to be reproduced, on a common backing to form a composite negative, said negatives of the pictorial matter having photogravure screen lines formed thereon land having less contrast than the line negatives, placing said composite negative in face-to-face intimate contact with a sensitized gelatinous film for a predetermined time interval, whereby certain portions o said film are rendered insoluble, transferring said film to the printing surface, removing the soluble portions of said film and etching said surface.

7. The process of preparing a photogravure printing surface which comprises the following steps: placing a photographically produced negative silver image of the matter to be reproduced in intimate contact with a gelatinous film in the presence of a chromate salt, removing said gelatinous film and transferring it to a photogravure surface,

o the line and pictorial p f produced in intimate contact with a washing away all soluble portions of said gelatmous matter, and etching said surface.

8. The process of preparing Va photogra- .vure printing surface which consists in placing a negative silver image of the matter to be reproduced in intimate contact with a gelatinous-film in the presence of a chromate salt, whereby portions of said gelatinous film corresponding to said image are rendered insoluble in direct proportion to the amount of silver present, transferring said film to a metal printing surface, washing away all soluble portions of said film, and etching said surface.

9. The process of preparing a photogravure print-ing surface which comprises the -following steps: placing a photographically produced negative image formed on a silver bromide film, of the matter to be reproduced,

'in intimatelcontact with a sensitized gelatinous film in the presence of a bi-chromate of an alkali, a ferricyanide ofan alkali, a soluble halid salt of an alkali, and water to cause an insoluble condition in certain portions of said gelatinous film correspondin to said negative image, transferring sai elatinous film to a printin surface, removing all soluble portions o film, and etching said surface in the presence of the remaining portion of said film.

l0. The process of preparing a photogravure printing surface which consists in placing a photographically produced negative image formed on a silver bromide film, of the matter to be reproduced, in intimate contact with a gelatinous film in the presence of a chromate salt, whereby a chemical action takes place between said silver bromide image and said chromate salt to cause certain portions of said gelatinous film to become insoluble in direct proportion to the amount of silver present in the negative image, transferring said gelatinous film to a previously repared metal surface, Washing away the soluble portions of said gelatinous film, and etching said surface in the presence of the remaining gelatin.

11.4 The process of producing a photogravure printing surface which comprises the following steps: placing a photographically produced negative image formed on a silver photographic paper of the matter to be regelatinous film sensitized with a chromate salt whereby portions of the gelatin in contact with said image are rendered insoluble in direct-proportion to the silver present at the points of contact, transferring and placing said gelatinous film in contact with the printing surface to be engraved, dissolving and removing all soluble portions of said gelatin, and etching said surface in the presence of the remaining gelatin.

12. The process of producing a photogravure printing surface which comprises the said gelatinous` following-steps: placing a photographically produced bromide paper negative of the image to be reproduced, in a moistened condltion, in face-to-face intimate contact with a gelatinous film sensitized and moistened wlth a. solution containing a chromate of salt, c ontinuing said contact fora predetermined time interval whereby portions of said gelatinous film in contact with said image are rendered insoluble in direct proportion to the silver present, removing said film, transferring and squeegeeing it to the surface to be engraved, washing away all soluble portions -of said film, and etching said surface in the presence of the remaining gelatin.

13. The process of producing a photogravure printing surface which comprises the following steps: placing a photographic paper containinw a silver salt, on whicha nega# tive image of the subject'to be reproduced has been projected and developed, in face to face intimate contact with a gelatinous film sensitized and moistened with a solution containing potassium bichromate-one part, potassium ferricyanide-one part, potassium bromide-one part, and water 8() parts, continuing said contact for a predetermined time interval whereby portions of the gelatin film in contact with the negative image are rendered insoluble in direct proportion to the silver present, transferring and squeegeeing said film to the surface to be engraved, washing away all soluble portions of said gelatin and etching said surface in the presence of the remaining gelatin.

14. The process of preparing a photogravure printing surface which consists in placing a sensitized 'photographic paperwhich has been photographically exposed to the matter to be reproduced and developed to produce a negative image containing reduced silver in intimate contact with a gelatinous film in the presence of a solution containing a chromate salt, whereby portions of said gelatinous film contacting with the silver image are rendered insoluble in direct pr0 portion to .the silver present, transferring said film to a metal surface on'which an insoluble gelatin screen formation has previously been applied, dissolving and Washing away all soluble portions film and etching said'surface in the presence of the remaining gelatin.

15. The process of producing a photogravure printing surface which comprises the following steps: placing a negative silver image on a photographic paper ofthe matter to be reproduced, in intimate contact with a gelatinous film having an insoluble screen formation thereon, said film being sensitized with a solution containing a chromate salt whereby the remaining soluble portions 0f said film are rendered insoluble in direct proportion to the silver present in said image, transferring and placing said film in of said gelatinV contact with the printing surface to be en. graved, dissolving and removing all solubltl portions of said gelatin, and etching said surface inthe presence of the remaining insoluble gelatin.

16. The process of preparing a photogravure printing surface which consists in sensitizinga gelatinous film with a solution containing potassium bichromate, light printing a half tone screen formation on said sensitized film, resensitizing said light printed film with a solution containing potassium bichromate, potassium ferrie anide and potassium bromide, placing sai film in a/moist condition in intimate face to face contact with a negative image, on silver bromide aper, of the matter to be reproduced whereby portions of said film not already rendered vinsoluble bv the light printing of said screen formation thereon are also rendered insoluble in direct proportion to the silver present in said image, transferring said film to a metal printing surface, washing'away all insoluble portions of said film and etching sril surface in the presence of the remaining 17 The process of preparing a photogravure printing surface which consists in light printing a photogravure screen formation on a photographic paper sensitized with a silver salt, photographing the matter to be reproduced on said screened paper, chemically treating said paper to produce a negative image in reduced silver of the matter to be reproduced superimposed on the screen formation, placing said negative image in intimate contact with a gelatinous film in the presence of a solution containing a chromate salt whereby portions of said film contactin with the silver image are rendered insolu le in direct proportion to the silver present, transferring said film to a metal printing surface, washing away all soluble portions of said film, and etching said surace.

18. The process of preparing a photogravure printing surface which consists in light printing a photogravure screen formation over a photographic exposure, on` a paper sensitized with a silver salt, of the matter to be reproduced, chemically treating said paper to produce a negative ima e in reduced silver of said matter and said screen formation, placing said negative image in intimate contact with a gelatinous film previously sensitized with a solution containing a chromate salt whereby portions of said film contacting with the silver image are rendered insoluble in direct proportion to the silver present, transferring sald film to a metal printing surface. washing away all soluble portions of said film and etching said surface.

, 19. The process of vure printing surface which consists in placpreparing a photogra ing a negative hotograph, containino reduced silver, of t e matter to be reproiuced in intimate Contact with a gelatinous film in the presence of a solution containing a chromate salt, whereby portions of said gelatinous film contacting With the silver image are rendered insoluble in direct proportion to the silver present, removing said lm from saidimage, light printing a photogravure screen formation on said lm without l0 further sensitizing, transferring said film to a metal printing surface, Washing awa all soluble portions of said film and etc ing said surface.

Dated New York, N. Y., January 7 1924.

RAYMOND N. GETCHES.

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