US2373489A - Halftone photoengraving process - Google Patents

Halftone photoengraving process Download PDF

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Publication number
US2373489A
US2373489A US41553041A US2373489A US 2373489 A US2373489 A US 2373489A US 41553041 A US41553041 A US 41553041A US 2373489 A US2373489 A US 2373489A
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Prior art keywords
light
screen
ultra
portions
line
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Priority to US41553041 priority Critical patent/US2373489A/en
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Publication of US2373489A publication Critical patent/US2373489A/en
Priority to GB2005647A priority patent/GB648686A/en
Priority to US3679448 priority patent/US2468680A/en
Anticipated expiration legal-status Critical
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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
    • G03F5/00—Screening processes; Screens therefor
    • G03F5/02—Screening processes; Screens therefor by projection methods
    • G03F5/12—Screening processes; Screens therefor by projection methods using other screens, e.g. granulated screen

Definitions

  • This invention relates to an improved halftone photoengraving process and an improved halftone screen for use in such process.
  • One of the objects of the invention is to provide to give printed illustrations which are characterized by the absence of screen pattern in the highlights, by clean solid lines and type devoid of screen pattern, and shaded portions which are reproduced with thaid of the screen pattern as dots depending for sizeupon the shading of the original artists drawing.
  • my invention involves the employment of two different kinds of light or, to he more enact, lighting of two ranges of wave length.
  • the plates employed are sensitive to both kinds of light.
  • My improved screen is provided with rulings or pattern composed of lines which are transparent or substantially transparcut to one kind of light, while they are opaque to the other kind of light.
  • terial to be reproduced is either prepared or treated so that the shaded portions thereof are made opaque to that kind of light for which the screen pattern is transparent.
  • the employment or ultra-violet and ordinary light is particularly advantageous in the preparation of the drawing, since the artist can, as will hereinafter he explained, employ pigments and colors which appear the eye similarly to pigments and colors heretofore used.
  • the pigments or colors may, however, as will hereinafter be described, contain material which renders them quite opaque to ultra-violet light. Consequently, the shaded portions will be quite onaque to ultra-violet light although to the eye of the artist, or indeed to the eye of any observer, they appear to he normal shaded
  • Fig. l is a plan view of a screen embodying my invention.
  • Fig. 2 is a plan view of one which my screen is fabricated
  • Fig. 3 is a cross-section of plate shown in 2; t
  • Fig. 4 is a similar cross-section of the modified has solid clacl: or violet light.
  • Fig.- 2 I have shown one sheet of glass having the lines is thereon.
  • the lines to and it Referring to the embodiment of Fig. '3, the
  • grooves 052 may be-rnade with a diamond cuttin device, the depth of the grooves being sufficient to allow for a deposit of a transparent resin or gelatinous material capable of transmitting near ultra-violet light, while absorbing visible actinic light.
  • Gelatin or polymerized methyl-methacrylate commonly known as Lucite, or Plexiglass, or indeed any medium which is transparent to ultraviolet light and which will carry the dye employed, may be used as a iilling medium for the grooves it.
  • These materials may be dyed with a pure grade of fuchsine and they then transmit light below 4,000 angstrom units and efi'e'ctually absorb light between 4,000 and 6,000 angstrom j veniently formed photographicaily from a master screen.
  • the first step is to expose and develop aphotographic plate so that the screenrulings appear as a silver image in the gelatine.
  • a suitable dye such as iuchsine is substituted for the reduced silver in thegelatlne coating on the plate by methods known in the art. The remaining undyed gelatlne maybe either removed or.
  • ultra-violet light-and-eflectively opaque to the actinic portion of ordinary light includenitroso-dimethylaniline, methyl violet, glass or gelatine suspensions of nickel and cobalt salts, and suspensions of cobalt chloride, copper sulfate, acetamine scarlet B.
  • the lines i0 and H may be of any desired number as in conventional screens.
  • the number of lines may be be-' tween 50 and 300m the inch.
  • The. artists drawing a fragment of which is; shown on enlarged scale in Fig. may be prepared in the usual way, with the addition that the shaded portions are treated so as to be opaque to ultra-violet light. This treatment should not affect the appearance of the "shaded portions? to the eye so that the artist may visually obtain the desired shading which he desires to appear in the final reproduction. Furthermore, the shaded portions must maintain their relation to actinic visible light so that they may register selectively upon the negative in accordance with their density on the original draw-- ing.
  • the quinine bisulfate is dissolved in we'- ter and the solution is used as a solvent for the water-color or ink pigment used to make the v Distilled water cc 1000 Quinine bisulfate grams 00 Sulphuric acid, C. P cc 10 Egg albumen, C. P grams 15
  • the sulphuric acid amplifiesthe fluorescent and absorption properties.
  • the egg albumen facilitates the smooth application of the pigment to the drawing. This solution is used instead of water as amedium for the artists pigment.
  • pigment may be of any usual type; for example, it may be Windsor Newton's water-color Lampblack which is representative of the type of materialcustomarily used in making wash drawings.
  • quinine bisulfate any other material, transparent to ordinary light and opaque to ultra-violet light, may be employed.
  • Other materials which may be substituted for quinine blsulfate to provide opacity to ultra-violet light include the following: anthracene, phenanthrene, various forms of naphthylamine disulphonic acid, beta. methyl umbelliierone, and para-hydroxy benzaldehyde.
  • the drawing will also include relatively large areas of solid color (not shown) but the optical behavior, unless additional steps are taken, is the same for solid color as for line.
  • the procedure of making the negative with the aid'of the artists drawing and employing-my improved screen described above may be effected in the normal manner.
  • the negative may be placed in a photoengraving camera, my improved screen may be located in the camera at the proper distance ahead of the plate, and the drawing which is to be copied is placed on a suitable support and illuminated by light.
  • the light must contain ultra-violet light and visible light.
  • all the light is derived from a single source which supplies both kinds of light.
  • the invention is not to be considered limited in this respect because two separate exposures may be made, one in which the positive is illuminated by visible light, and another in which the positive is illuminated by ultra-violet light. The result is the same in both cases.
  • Such a source for a visible light and ultra-violet light may suitably be any of the ordinary white-flame carbon arcs which radiate amply in the ultra-violet region and also in the visible region.
  • I may also use a lamp manufactured by the General Electric Lompany oi.Los Angeles, California, which consists of a high-intensity 'mercurywapor argon-filled arc lamp in a double none ⁇ ; or quartz nonex envelope.
  • Light rich in ultra-violet is generated by electronic disturbances between two barium oxide coated cathode elements in the inner tube.
  • the now popular mercury vapor lamps may also be used as an efiective light source.
  • the picture reflects no ultra -violet light from the line portions l6 and ill, no ultravioletlight'irom "shaded portions id and it), and no light from solid color portions.
  • the highlight portions l3 reflect the ultra-violet light and that ultra-violet light passes directly through all portions of the screen corresponding thereto.
  • the screen is areal operative screen for visible light.
  • The'lines W'of the screen are opaque to visible" light and consequently the normal screen action occurs in the negative (Fig, 'I).
  • the light shaded" portion i l gives lalrge overlapping dots of reduced silver as shown in the upper left-hand corner of fig. 7, while the heavily shaded portion it gives small dots corresponding to the openings in the screen as shown in the right-hand top corner of Fig. 7.
  • the shaded portions print on the negative (Fig. 7) in the usual manner.
  • the visible light reflected by the highlight portions it does not affect the corresponding portions of the negative (Fig. 7) for the reason that the ultra-violet light reflected from the highlight portions l3 passes through the corresponding portions of the screen as if it were fully transparent.
  • Fig. 8 isan enlargement corresponding to Fig. 'I of a negative produced according to standard practice, the degree of enlargement being the same in both cases. The manner in which the fine line is lost and the sharp contour of "type is completely obliterated, will readily'be seen from Fig. 8.
  • Flashing may be effected simply by placing a layer of tissue paper over the drawing of Fig. 5, and then drawing on. the tissu paper in black, matter corresponding .to the line" is and the "type II. This may be done quite roughly provided the roughlyapplied color does not overlie solid color portions of considerable size and in which it is desired to create screen pattern.
  • negative has highlights without screen not tern, shaded portions with screen pattern, and line portions without screen pattern and without screen-pattern deformation, which consists inrendering the'work areas of said pictorial representation absorbent of ultra-violet light, and photographically exposing a plate to form the negative by means of visible actinic and ultraviolet light through a screen having line elements opaque to actinic visible light and transparent to ultra-violet light.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Printing Methods (AREA)
  • Overhead Projectors And Projection Screens (AREA)
US41553041 1941-10-18 1941-10-18 Halftone photoengraving process Expired - Lifetime US2373489A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US41553041 US2373489A (en) 1941-10-18 1941-10-18 Halftone photoengraving process
GB2005647A GB648686A (enrdf_load_stackoverflow) 1941-10-18 1947-07-25
US3679448 US2468680A (en) 1941-10-18 1948-07-02 Halftone screen for use in the

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US41553041 US2373489A (en) 1941-10-18 1941-10-18 Halftone photoengraving process
US3679448 US2468680A (en) 1941-10-18 1948-07-02 Halftone screen for use in the

Publications (1)

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US2373489A true US2373489A (en) 1945-04-10

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US41553041 Expired - Lifetime US2373489A (en) 1941-10-18 1941-10-18 Halftone photoengraving process
US3679448 Expired - Lifetime US2468680A (en) 1941-10-18 1948-07-02 Halftone screen for use in the

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Application Number Title Priority Date Filing Date
US3679448 Expired - Lifetime US2468680A (en) 1941-10-18 1948-07-02 Halftone screen for use in the

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GB (1) GB648686A (enrdf_load_stackoverflow)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2983604A (en) * 1955-11-03 1961-05-09 Gen Aniline & Film Corp Quenching solution for fluorescent photographic paper employed in the manufacture ofhalftone negatives
US3352728A (en) * 1963-12-13 1967-11-14 Keuffel & Esser Co Material and method for making stencil masters
US3904420A (en) * 1972-08-31 1975-09-09 Eastman Kodak Co Information receiving element containing a yellow dye and an optical brightener

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3647471A (en) * 1969-11-19 1972-03-07 Lockheed Aircraft Corp Photographic reproduction of halftone screens

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1162162A (en) * 1913-05-09 1915-11-30 Mabel K Hatt Process of producing printing-plates.
US1988891A (en) * 1931-07-23 1935-01-22 Gaspar Bela Method of producing photographs in two or more colors
US2304988A (en) * 1940-04-19 1942-12-15 Eastman Kodak Co Photomechanical reproduction

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2983604A (en) * 1955-11-03 1961-05-09 Gen Aniline & Film Corp Quenching solution for fluorescent photographic paper employed in the manufacture ofhalftone negatives
US3352728A (en) * 1963-12-13 1967-11-14 Keuffel & Esser Co Material and method for making stencil masters
US3904420A (en) * 1972-08-31 1975-09-09 Eastman Kodak Co Information receiving element containing a yellow dye and an optical brightener

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Publication number Publication date
GB648686A (enrdf_load_stackoverflow) 1951-01-10
US2468680A (en) 1949-04-26

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