US1843872A - Process of making printing plates - Google Patents

Process of making printing plates Download PDF

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Publication number
US1843872A
US1843872A US370629A US37062929A US1843872A US 1843872 A US1843872 A US 1843872A US 370629 A US370629 A US 370629A US 37062929 A US37062929 A US 37062929A US 1843872 A US1843872 A US 1843872A
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United States
Prior art keywords
printing
plate
image
plates
light
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Expired - Lifetime
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US370629A
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English (en)
Inventor
Rudolph A Glaser
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POSTERGRAPH Inc
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POSTERGRAPH Inc
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Filing date
Publication date
Priority claimed from US295266A external-priority patent/US1789138A/en
Application filed by POSTERGRAPH Inc filed Critical POSTERGRAPH Inc
Priority to US370629A priority Critical patent/US1843872A/en
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Publication of US1843872A publication Critical patent/US1843872A/en
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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/20—Exposure; Apparatus therefor
    • G03F7/2002—Exposure; Apparatus therefor with visible light or UV light, through an original having an opaque pattern on a transparent support, e.g. film printing, projection printing; by reflection of visible or UV light from an original such as a printed image
    • G03F7/201—Exposure; Apparatus therefor with visible light or UV light, through an original having an opaque pattern on a transparent support, e.g. film printing, projection printing; by reflection of visible or UV light from an original such as a printed image characterised by an oblique exposure; characterised by the use of plural sources; characterised by the rotation of the optical device; characterised by a relative movement of the optical device, the light source, the sensitive system or the mask

Definitions

  • This invention relates to printing plates and to processes of making printing plates generally, but is particularly advantageous as appliedto printing plates made by the photographic projection method.
  • the application is a continuation in part of my prior applications Ser. No.”235,351, filed November 23, 1927, and Ser. No. 295,266, filed July 25,1928.
  • the invention although adaptable to printing generally, is especially adaptable for pictorial multi-color work and is applicable to printing any number of colors desired, and
  • the process preferably starts with the artists original paintin colored drawin or anv nflmr onnv.
  • rphotographic plates may be either screen produced as by half-tone, mezzograph or other screens, or clear, depending upon whether or not a halftone, lnezzograph or other lithographic screen is to be used-in the projection apparatus, then projecting the images of the color separation negatives or positives, directly upon the sensitized grained surface of the printing plates by the action of actinic light rays of high intensity, in a suitable projection apparatus, followed by treatment of each printing plate with a developer to develop the printing image firmly ingrained in and penetrating the plate, and cleaning up or rolling up and inking in the plate if it is to be used as a lithographic plate, or etching if it is to be used forglirect printing.
  • Fig. 1 is a side view of projecting apparatus suitable for transferring the images from the color separation plates to the sevcral color plates; 7
  • Fig. 2 is a diagram illustrating the opera tion of projecting an image from a photographic plate through a suitable screen upon a printing plate;
  • Fig. 3 is a similar diagram illustrating the operation of projecting an image from a photographic plate 11 on a printing plate but ,without'the screen or breaking the image up i-nto printing dots;
  • Figs. 4 to 8, inclusive are diagrams'of the successive stages in the manipulationof the printing plate showing the development of V the image and the formation of the printing surface for lithographic ofiset printing.
  • the color separation is made with three color filters only, red for the blue ink plate, green for the red ink plate, and blue for the yellow ink plate, the darker shades and blacks being obtained by printing I these colors one on top of another, although an additional plate may be made with a yel- 1 low filter for printing black if desired.
  • the color separations are preferably made upon standard dry plates, preferably the same kind of plate being used for all colors, and the exposure and treatment of all negatives being similar in order to preserve the proper tone values and avoid as far as possible the necessity for retouching and etching the prmting plates later on. If correct color separation negatives have been made, color correction by an artist is not necessary. If, however, the color separation negatives require correcting, this can be done by well known existin methods.
  • the projection of the several color separation negatives upon the respective printmg plates may be accomplished by means of any suitable enlarging camera.
  • the apparatus represented in Fig. 1 has been found satisfactory for this purpose, consisting of an arc lamp 10 or other source of high intensity light containing a large proportion of actinic rays suitable for photographic purposes, slidably mounted on rails 11 independently of the camera support, and arranged in connection with a condensing lens 12 mounted in the camera to project a beam of light through the negative 13 (see Figs.
  • the manner of projecting the image upon printing plates may be advantageously carried out as described above and as shown in Fig. 3; but instead, the negative may be clear and the image broken up into dot formation by projection through a half-tone, mezzograph or other lithographic screen 18 (as shown in Figsl and 2) positioned in front of the printing plate 16, and so arranged that the distance between the screen 18 and plate 16 may be adjusted to produce a printing dot to suit the character of the print and the ink.
  • the screen is adjustable toward and from the plate holder 17 by means of adjustable members 19, and may be removed and another screen substituted having a different texture of grain if desired.
  • a suitable source of light is an arc lamp such as is used for search lights and projecting motion pictures, and which has the horizontal carbon 20 constantly rotating, being driven through suitable gearing from the motor 21, so as to keep the arc steady in one place and permit of the rays from the crater being selected by the condenser, these rays being much more actinic' than those from the exterior of the corona.
  • the rotation of the horizontal carbon of the arc causes the spot of light ofhighest intensity to move in a minute circle around the axis of rotation of the carbon, projecting each white dot in the negative or screen as the case may be, as, a small pencil. of light which impinges on the plate in a circle around the true projected position of the dot and thereby causes the disintegration of the light sensitive coating more or less, depending upon the intensity of the light'action thereon.
  • the dots composing the projected image thus consist of a central area strongly acted upon by the pencil of light surrounded by a penumbra less strongly acted upon.
  • the tone of the image may be controlled, and the high lights .freed from dots and the shadows made solid, iii-desired. This permits the use-of the same color separation negative for producing two color plates having similar characteristics, as for example, light and dark blue, although better results may usually be obtained by making aseparate color separation negative for each plate.
  • the photographic negative holder 14 and printing plate holder 17 must be so constructed as to hold the negatives and plates in exact alinement parallel to each other and at exactly the proper distances, respectively, from the objective 15, in order that the several negative projections shall register properly upon the plates. It is important that the negative holder be free from vibration in its own plane, as otherwise the dots in the image will not'be sharp. Improved apparatus for this purpose, permitting of rapl and exact removal and replacement of the negatives, screens and plates, has been devised by me and is clearly described in my parent application above referred to and my copending applications Ser. No. 230,133, filed October 31, 1927, and Ser. No. 371,002 filed June 4, 1929.
  • the photographic negative and printing plate holders, the projection lens 15 and other camera parts are securely mounted on a bed consisting of I-beams or other suitable rigid supports 31 supported by springs 32, so as to reduce vibration from movementprepared according to any desired method for making line or half tone, mezzograph or other type of photo reproduction, using a fine screen for breaking up the image into printing dots 'so that upon enlargement in the projection apparatus the dots will be a size suitable for printing.
  • the printing plate is an important element of the invention and is prepared as follows:
  • the slightly .sensitized coating 36 is then flashed or exposed to light for a short interval, to harden it, whereupon it is wetted and coated again with sensitized gelatine or albumen, the
  • the light sensitive coatings 36 and 37 should be of such character as will be penetrated and disintegrated by the intense light from the rotating carbon lamp 10, as indicated in Fig. 6, where the light struck portions 38 and the non-light struck portions 39 are clearly indicated.
  • the wellknown bichromated gelatine or albumen coatings are satisfactory, but may be improved by treatment as hereinafter described.
  • the effect of the light rays upon the sensitized surface of the plate be as monochromatic as possible, thus avoiding the corona effect due to the different foci ofthe several kinds of rays emanating from the light source and consequent haziness in the printed copies.
  • the length of exposure should be timed to suit the density of the negative and the amount of enlargement, and may vary from a few seconds to a longer period.
  • the exposure of the plates for printing the lighter shades is shorter than those for printing the darker ones, due to the stronger light action.
  • the exposed plates are flowed with a developing and penetrating composition containing a water repelling substance, preferably an asphaltum mixture containing a greasy ink, which composition is spread evenly and allowed to dry.
  • a developing and penetrating composition containing a water repelling substance, preferably an asphaltum mixture containing a greasy ink, which composition is spread evenly and allowed to dry.
  • a water repelling substance preferably an asphaltum mixture containing a greasy ink
  • a composition suitable for the purpose is as follows: 0
  • the plate is then powdered with soapstone and cleaned with tannic acid and resin, or other suitable cleaning composition, following which it may be treated again with asphaltum mixed with benzol, or asphaltum varnish, to strengthen the image, and any touching up needed may be given to it in manner known in the lithographic art be ore rolling it up or etching with acid to make it ready for the press in the usual way.
  • Bothlithographic and deep etched plates may be produced in this manner for offset and dry printing.
  • Printing plates produced as above described are more faithful reproductions of the original copy than those produced by mean of paper transfers, which are subject to'distortion of the image both by stretching of the paper and squeezing of the transfer ink on the surface of the paper by the heavy pressure of the transfer press.
  • the process is very rapid, requiring but a few hours for the completion of a set of .plates for printing in three or more colors, and is correspondingly cheap on account of the operations being mostly such as can be performed by ordinary work men without re eated etching and special treatment by artists to correct the color and tone values.
  • the method of making lithographic printing plates photographically which consists in projecting a suitable photographic image upon the sensitized surface of a printing plate by concentrating the actinic rays of a beam of light of high intensity selected from the-crater of a rotating are through a suitable photographic negative, and through a projecting lens directly upon said sensitized surface of said plate, and developing the image thus produced upon said plate to receive ink.
  • the method of making lithographic printing plates photographically which consists in projecting a suitable photographic image upon a sensitized surface of a printing plate by concentrating the actinic rays of a beam of light of high intensity selected from oping medium.
  • the process of making multi-color printing plates which comprises making a series of color separation negatives or positives by photographing the original subject through color filters, and projecting the color separation images by an unobstructed beam of light through a lithographic screen directly upon suitably prepared light sensitive printing plates.
  • the process of making multi-color printing plates which comprises making a series of color separation negatives or posimary color, and projecting the color separation images each through a selected litho graphic screen for the particular shade of color desired, directly upon suitably prepared light sensitive printing plates.
  • the process of making multi-color printing plates which comprises preparing the color separation negatives or positives through color filters corresponding to the primary colors, and projecting the respective images upon a series of light sensitive printing plates, one for each color of ink desired, the projection being made through the primary color separation image corresponding to the color and the one of a series of lithograph screens of graduated grain corresponding to the ink to be used 'on the particular plate, and the exposure being made to suit the shade or tint, substantially as described.
  • sensitized coating for the printing plate is sensitive to the most actinic of the rays of said light and isinsensitive to all other rays.
  • step of the method of forming enlarged photographic printing members characterized by minute printing dots from smaller photographic plates which consists in projecting a beam of light from a light source moving in a closed path transversely of the axis of said beam through a screen produced photographic plate and a suitable projecting lens directly upon a light sensitive surface of a printing plate to change the character of "said light sensitive surface according to the image ofthe photographic plate.
  • the method of transferring photographic images upon the light sensitive surface of the printing member which consists in making a screen produced photographic reproduction of the image upon a transparent plate, mounting said plate and sensitized printing member in parallelism in an enlarging camera with a projection lens between them, collecting actinic rays from a powerful light source and passing through the transparent plate in a parallel beam, moving the light source in a closed path transversely of the axis of the beam, and projecting the image thus produced upon the sensitized printing member for a predetermined time while maintaining said plate and printing member immovable.
  • a printing plate of the type produced by the graduated tone process having a characteristic arrangement of ink-receivlng areas with sharp outline conforming to a photographic image havin' a characteristic screen formation projecte upon the printing plate by the action of high intensity light, such that the ink-receiving areas penetrate said plate and have a graduated intensity of penetration greatest in the center.
  • a printing plate of the type produced by the graduated tone process having the characteristic arrangement of ink-receiving areaswith sharp outline conforming to a photographic image projected from a screened negative directly upon said plate by the action of high intensity light, such that the ink-receiving areas penetrate said plate and have a graduated intensity of penetration greatest in the center.
  • the step in the production of printing plates which comprises projecting a photographic reproduction directly onto a sensitized surface by means of rays of actinic light emanating from a regular moving source rotatlng about the axis of projection and of suffi c1ent intensity to disintegrate said sensitlzed surface according to the characteristics of the projected image.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Printing Methods (AREA)
  • Photosensitive Polymer And Photoresist Processing (AREA)
US370629A 1927-11-23 1929-06-13 Process of making printing plates Expired - Lifetime US1843872A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US370629A US1843872A (en) 1927-11-23 1929-06-13 Process of making printing plates

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US23535127A 1927-11-23 1927-11-23
US295266A US1789138A (en) 1928-07-25 1928-07-25 Printing plate and process of making same
US370629A US1843872A (en) 1927-11-23 1929-06-13 Process of making printing plates

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US1843872A true US1843872A (en) 1932-02-02

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US370629A Expired - Lifetime US1843872A (en) 1927-11-23 1929-06-13 Process of making printing plates

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US (1) US1843872A (en, 2012)
BE (1) BE356020A (en, 2012)
DE (1) DE558958C (en, 2012)
GB (1) GB301031A (en, 2012)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2507788A1 (fr) * 1981-06-15 1982-12-17 Charpiot Serge Procede et appareils pour la sensibilisation d'ecrans serigraphiques
FR2675279A1 (fr) * 1991-04-15 1992-10-16 Arts Graphiques Systemes Dispositif de projection directe d'ecrans serigraphiques a l'aide d'une source ultraviolet.

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2507788A1 (fr) * 1981-06-15 1982-12-17 Charpiot Serge Procede et appareils pour la sensibilisation d'ecrans serigraphiques
FR2675279A1 (fr) * 1991-04-15 1992-10-16 Arts Graphiques Systemes Dispositif de projection directe d'ecrans serigraphiques a l'aide d'une source ultraviolet.

Also Published As

Publication number Publication date
GB301031A (en) 1930-05-21
DE558958C (de) 1932-09-13
BE356020A (en, 2012) 1928-12-31

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