US2148519A - Process of making printing plates - Google Patents

Process of making printing plates Download PDF

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Publication number
US2148519A
US2148519A US159895A US15989537A US2148519A US 2148519 A US2148519 A US 2148519A US 159895 A US159895 A US 159895A US 15989537 A US15989537 A US 15989537A US 2148519 A US2148519 A US 2148519A
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United States
Prior art keywords
subject
dots
transparency
making
positive
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Expired - Lifetime
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US159895A
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English (en)
Inventor
William J Wilkinson
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Miehle Printing Press and Manufacturing Co
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Individual
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Publication date
Priority to BE414886D priority Critical patent/BE414886A/xx
Priority to NL46830D priority patent/NL46830C/xx
Priority to GB9868/36A priority patent/GB472915A/en
Priority to FR809516D priority patent/FR809516A/fr
Application filed by Individual filed Critical Individual
Priority to US159895A priority patent/US2148519A/en
Application granted granted Critical
Publication of US2148519A publication Critical patent/US2148519A/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
    • G03F5/00—Screening processes; Screens therefor
    • G03F5/20—Screening processes; Screens therefor using screens for gravure printing
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R11/00—Electromechanical arrangements for measuring time integral of electric power or current, e.g. of consumption
    • G01R11/02—Constructional details
    • G01R11/10—Braking magnets; Damping arrangements

Definitions

  • the present invention relates to the preparation of intaglio-plates for gravure-printing, and it pertains more particularly to the making of intaglio printing-platesin the surfaces of which the various tones of the subject are represented by ink-wells of diiiferent' or graduated sizes or areas and of approximately the same depth, the invention concerning especially the making of the positive-transparencies from which such printing-plates are produced.
  • the invention provides a novel process for the creation of a positive-transpar: ency, a printing-plate, and a print, having inkwell or dot formation, as the case may be, of the kind mentioned above, from a conventional halftone screen print or printing-plate of the character adapted for use in relief-printing as distinguished from gravure-printing.
  • the ink-wells of the printing-plate including those of the deepest shadows or solids, must be practically separated from one another to provide sufilcient surface on the plate to support the ink-wiping doctor-blade adequately to prevent its extraction of the ink from the wells, whereas ordinary half-tone screen dotformations with interconnected or blended dots in the solids do not comply with this essential need.
  • Another aim of the invention is to produce intaglio printing-plates which will correctly represent the characteristics of the original subject without requiring individual correction.
  • a further design of the invention is to supply a novel procedure whereby the gravure printingplate produced from an ordinary half-tone screen plate or half-tone screen print will have a new dot-formation different from that of such plate or print.
  • An additional characteristic of the invention resides in the provision of a cheap, simple and dependable method of accomplishing the stated aims and objects of the invention.
  • a feature oi. the invention consists in making a half-tone screen print from a printing-plate having the usual half-tone screen dot-formation with interconnected dots in the solids, or the plate itself may be used instead 0! the print, provided the plate is properly coated with a suitable substance; making a photographic-negative from such half-tone screen print or plate and in which negative the dots are, diflused or blurred and obliterated to as great an extent as possible but not to such a degree as to materially reduce the sharpness of the image; making a photographic positive-transparency of such negative using a screen in a manner to produce the dotformation required for the gravure or intaglio plate, with the screen so disposed with respect to the negative as to substantially block out the remaining features of the original screen-iormasuch as a moir pattern; and making from such transparency the intaglio printing-plate photographically and by etching.
  • the positivetransparency representing each color is produced in this manner and a set of intaglio printingplates is made from the final positive-transparencies.
  • Any type-matter, or similar printed matter, appearing with the original picture may be treated separately because it appears in continuous-tone on the plate or print and does not contain any half-tone screen dots which require obliteration prior to the production of the gravure dot-formation.
  • FIG. 1 illustrates an ordinary, half-tone,v
  • screen printing-plate or print having a dot-formation adapted for, or characteristic of, reliefprinting and which comprises the copy to be employed in performing the new and improved process;
  • Figure 2 shows a negative, made from the plate or print of Figure 1, in which the half-tone screen dots have been somewhat blurred or obliterated;
  • Figure 3 illustrates a hemi-tone, screen, reduced-tone-value positive-transparency, produced by the present process from the blurred negative shown in Figure 2, having the desired different or new dot-formation adapted for intaglio printing.
  • a proof is made of each plate in black ink on a good quality coated paper, it being desirable that these proofs be of the best grade and they are, therefore, preferably made on an engravers proofing-press.
  • Each of these black proofs constitutes a halftone, screen, color-separation print of the original picture to be reproduced, and each has a dotformation of the species used in relief-printing, as illustrated in Figure 1, as comprising, except in the darkest tone or solid, rows of dots differing in size according to the tones to be reproduced, each dot being relatively sharp and distinct, the dots being progressively larger as the tones become darker and, in the blacks or solids, merging into one another to form a continuous-tone.
  • each such proof was made from a plate produced with ahalf-tone screen having lines crossed at right-angles to one another and extending at an angle of 45 to the horizontal, which will be referred to herein as a 45 screenposition, this being the position commonly used for black plates.
  • a set of electro-type plates made therefrom may be used for the same purpose.
  • the original set of printing-plates may be dispensed with and a good, half-tone, screen print of each plate may be substituted therefor, in which case the above step would be eliminated and the half-tone screen prints would be utilized for the subsequent steps of the process, thereby saving the expense of making a separate set of plates for each periodical.
  • the sets of half-tone screen prints could be made from a single set of printing-plates and one set of such prints submitted to each perodical together with a set of progressive color proofs, it being understood, that the prints need not be the exact size required for. printing in the perodical as they may be enlarged or reduced as is desired during the subsequent steps of the process.
  • a negative of each black, half-tone, screen proof is made in the camera by photographing the proof on a dry-plate or a wet-plate as may be preferred, such .negaiive then being opaqued, if required, in any convenient manner, where the proof indicates pure white, such a negative being illustrated in Figure 2 of the drawing.
  • This photographic-negative represents a condition in which the original dot-formation of the proof has been largely destroyed in the negative and in the latter there is an approximation to a continuous-tone although the sharpness of the image remains.
  • Register-marks are placed on each negative corresponding exactly with each other for colorprinting, a set of positive-transparencies is made in a camera from these negatives through a halftone or other appropriate screen adapted to produce the desired new dot-formation, preferably, but not necessarily, by the wet-plate process, and if the negatives are not of the correct size for the printing-plates, they may be reduced or enlarged as required in this step of the process.
  • Such half-tone screen may be the same as, or
  • a 150-line screen is at present preferred, although such screen ruling may be changed if desired.
  • the screen When the negative is in position and the screen is in place in the camera, the screen may be turned from the original screen-position to a diiferent screen-angle, such that the original screen-effect is substantially blocked out or obliterated and all irregularities, such as moir effects, are eliminated.
  • the angle of change required to eflace or extinguish the original screen-eflect differs somewhat according to the change in screen size and the color represented by the separation-negative.
  • the separation-negatives In color-printing, it is customary to make the separation-negatives with screens at diflerent angles to the horizontal and, as a specific example, the angles may be as followsz-yellow 90, red blue 75, and black 45.
  • a screen at 45 produces half-tone dots that appear in vertical rows as illustrated in Figure 1, and, for the various other angles, the rows of dots are inclined in the degree indicated.
  • the screen is preferably displaced angularly equally with respect to the original screen position in each print, so that the relative angles remain the same, this in eflect transposing the screen-angle of the red, blue and black prints,
  • yellow takes a new angle not originally used; for example, the new angles may be as follows: yellow 30", red 45", blue 15, black 75.
  • angles may be varied as'required in any particular instance, and, obviously, if a different number of plates are used, the angles for the several plates may be set in the same manner.
  • the screendistance from the light-sensitive plate to form the positive-transparency from the dot-blurred negative, the size of the screen-openings, the camera-extension, the stop and the exposure are made such that the photographic positive-transparency shows a dot-formation in which the dots representing the blacks or solids are substantially or approximately entirely disconnected, as shown in Figure 3, except possibly in the very deepest solids or blacks where they may be connected at their corners, but are not so large as to form acontinuous tone, and in which the dots graduate in size from the solids to the lightest tones and are either entirely absent from the whites or are so minute thereon that they can be readilyremoved by a suitable reducing-agent.
  • Each such positive-transparency which has all of the tones of the same color of the original half-tone print at materially reduced value, that is, about one-half, as is clearly depicted in such Figure 3, has been aptly characterized as a hemitone positive-transparency, because it is practically a true half-tone, to distinguish it from an ordinary half-tone (see Figure 1), which is more or less of a misnomer in that such halftone is of much more than one-half tone-value.
  • an ordinary half-tone or similar screen is so associated with, or placed at such a distance in front of, the light-sensitive plate or film on which the positive-transparency is to be made and through which screen the light is projected onto the plate or film, that the darkest parts or solids of the original subject, such as deep shadows, appear in this positivetranspar ency merely as intermediate, checkerboard or middle tones and the remainder of the positivetransparency is comprised of all lesser tones graduating properly down to practically an absence of dots.
  • such-screen-distance may be about three-fourths that which would be used for the production of an ordinary half-tone and the exposure may be in the neighborhood of approximately one-third that which could be satisfactorily employed for the making of a halftone; but, it is to be understood, that these factors are variable depending upon other features, such as the characteristics of the original subject, the intensity of the light, the speed of the emulsion, etc.
  • tone-value or itsequivalent has been used in reference to the original halftone subject, it is intended to mean the relative position of the tone of any particular color in a scale which represents the full range of the color in question; when employed in relation to the blurred-dot negative, it signifies the value of the density or opaqueness of the tone; when used in reference to the hemi-tone positive-transparency, it specifies the relation between the total area of the opaque dots to the area of the transparent surface in a unit area of the tone under consideration of the positive, it being borne in mind that all dots in the positive-transparency are of equal density regardless of size; and when employed in reference to the hemi-tone gravure printing-plate, hereinafter referred to in more detail, it means the relation between the area of the ink-wells to the area of the non-printing surface in a unit area of the tone under consideration in the printing-plate.
  • positive transparencies are now used for the production of the intaglio-printing-plates in any convenient manner; for example, the positive-transparencies may be printed in the usual way on carbon-tissues which are transferred to plates, suchas copper, stripped of their backings and developed, and the plates etched with an etching-solution of, for instance, 40 Baum perchloride of iron; or these positive-transparencies may be printed by contact on metal plates or rollers previously coated with a bichromated solution of shellac or glue which, after development, may be etched in a manner well known in the art.
  • the etching process is preferably so conducted as to reproduce the dots as entirely disconnected wells in the plates, except possibly in the darkest areas or solids where they may be connected in minor degree, although the dividing walls between the wells should not be broken down to an extent such that the remaining metal is incapable of properly supporting the doctor-blade during the gravure printing operation.
  • the etching of the intaglio-printing-plates is carried out long enough to assure that the many practically-independent etched wells in the surface of the plates are deep enough to accommodate sufficient ink so that when the printing is done, there will be enough ink applied to the print by all wells to permit a proper spreading thereof whereby to give the print a full range of tone gradations from the darkest shadows or solids to the brightest high-lights; this ink enlargement or spread of the dots on the print making good or overcoming the lack of full intensity of the posifive-transparency, such spreading of the ink on the print taking place in more or less degree for all printed dots.
  • Another, and perhaps preferable, mode of practicing the invention which procedure is not however essential, but which has certain advantages of affording more leeway or greater latitude in the time of light exposure in making the positivetransparency and of the production of sharper and more clearly defined dots and which may be accomplished by a slight change in the indicated distance between the screen and the film which is to form the positive-transparency, or by a 'slightly longer exposure, or both, comprises making a positive-transparency under conditions such that the whites of the subject are represented therein by extremely-fine dots which the capable of being entirely removed by an ordinary reducing operation, and, in eliminating these by such reduction, all of the remaining dots of the positive will be reduced a certain uniform extent, the specified reduction being controlled so as to remove the dots on the whites without entirely eradicating the dots representing the next darkershade, and in this way, all of the tone values of the picture are preserved, although the positive-transparency, when viewed by itself, as stated above, shows less contrast and appears flatter than the original subject.
  • the original dot-formation is destroyed in the negative by first photographing with the dots out-of-focus, whereby a blurred or fuzzy appearance is obtained while retaining the sharp characteristics of the image, and then photographing the negative thus obtained through the screen, which is so disposed as to substantially remove the residual effect of the original dotformatlon, and to substitute the new dot formation therefor.
  • the image constitutes a picture or the like which is represented in ordinary half-tone dots, but, if type or other printed matter is included with the picture, the type may be treated separately inasmuch as it appears in full tone and does not contain half-tone dots which must be obliterated.
  • a separate negative is made of the type-matter in which the focus has been brought to perfect sharpness, and from this negative a hemi-tone positive-transparency is made through a half -tone screen under conditions such that the dots barely touch each other or are entirely disconnected, so that, when the printing-plate is made therefrom, they will produce practicallydisconnected wells as above mentioned.
  • This positive-transparency of the type may be assembled with the positive-transparency of the black-plate or of a plate representing the color in which the printing is to appear, as by a photocomposing machine, and the composite material may be etched on the metal plate in any desired manner.
  • the hemi-tone positive-transparencies instead of being produced in a camera, may be made from the blurred negatives by the direct contact method by the employment of dry-plates instead of wet-plates and a 150-linescreen may be used for this purpose, under which circumstances, it has been found that an appropriate distance between the screen and the light-sensitive plate undergoing exposuremay be approximately .190 inch.
  • the screen used in front of it maybe in the same angular position as that of the original half-tone subject.
  • the positivetransparencies and the printing-plates made therefrom are capable of representing all tones of the subject from white to the darkest although at reduced values, no tones being precluded from proper representation therein by any steps in the process.
  • the metal-plate maybe coated with a lightsensitive, so-called cold-enamel, which is subjected to the action of light through the positive-transparency, this coating being capable after development of remaining substantially unimpaired during and after etching of the plate through dot-like apertures therethrough, this permitting a proof to be taken while the coating is intact on the plate to determine if the etching has proceeded to the desired extent, a singlestrength etching-fluid only being used.
  • a lightsensitive so-called cold-enamel
  • the negative into a different set of comparatively-sharp dots of substantiallyequal density in the transparency with the dots representing the solids, if any, of the subject in approximate checkerboard-design and the dots representing all lesser tones of the subject sep arated from one another and of graduated areas.
  • the subject are represented at approximately one-half value and in the making 0! said positive-transparency converting the set of blurred dots of the negative into a different set of comparativelysharp dots of substantially-equal density in the transparency with the dots representing the solids, if any, of the subjectin approximate checkerboard-design and the dots representing all lesser tones oi the subject separated from one another and of graduated areas.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Braking Arrangements (AREA)
  • Manufacture Or Reproduction Of Printing Formes (AREA)
US159895A 1935-04-11 1937-08-19 Process of making printing plates Expired - Lifetime US2148519A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
BE414886D BE414886A (xx) 1935-04-11
NL46830D NL46830C (xx) 1935-04-11
GB9868/36A GB472915A (en) 1935-04-11 1936-04-03 Improvements relating to permanent magnets for electricity meters
FR809516D FR809516A (fr) 1935-04-11 1936-04-06 Procédé pour établir des plaques ou formes pour l'impression monochrome ou polychrome, notamment des plaques ou formes en creux pour l'impression en taille douce
US159895A US2148519A (en) 1935-04-11 1937-08-19 Process of making printing plates

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US1586035A 1935-04-11 1935-04-11
US159895A US2148519A (en) 1935-04-11 1937-08-19 Process of making printing plates

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US2148519A true US2148519A (en) 1939-02-28

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US159895A Expired - Lifetime US2148519A (en) 1935-04-11 1937-08-19 Process of making printing plates

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US (1) US2148519A (xx)
BE (1) BE414886A (xx)
FR (1) FR809516A (xx)
GB (1) GB472915A (xx)
NL (1) NL46830C (xx)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2596115A (en) * 1945-12-26 1952-05-13 Lucien C Austin Screened positive for use in preparation of intaglio printing plates and method of making said positive
US3210186A (en) * 1959-12-03 1965-10-05 Gorig Josef Intaglio printing screen for superimposing with autotypy screen positives in the production of etchings for autotypical intaglio printing

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2596115A (en) * 1945-12-26 1952-05-13 Lucien C Austin Screened positive for use in preparation of intaglio printing plates and method of making said positive
US3210186A (en) * 1959-12-03 1965-10-05 Gorig Josef Intaglio printing screen for superimposing with autotypy screen positives in the production of etchings for autotypical intaglio printing

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Publication number Publication date
FR809516A (fr) 1937-03-04
NL46830C (xx)
BE414886A (xx)
GB472915A (en) 1937-10-04

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