US2100346A - Intaglio printing elements and method of producing the same - Google Patents

Description

1937- w. N. MISURACA INTAGLIO PRINTING ELEMENTS AND METHOD OF PRODUCING THE SAME Filed June 8, 19-33 2 Sheets-Sheet l 0 a o o u 0 a ll o o n o a.

INVENTOR.

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INTAGLIO PRINTING ELEMENTS AND METHOD OF PRODUCING THE SAME Filed June 8, 1933 atented Nov. 30, 1937 ED STATES INTAGLIO PRINTING ELEMENTS AND METHOD OF PRODUCING THE SAME William N. Misuraca, Merrick, N. Y., assignor to Photo-Cylinder New York Corporation, a corporation of Application June 8, 1933, Serial No. 674,802

13 Claims.

This invention relates to intaglio printing ele ments for use in photogravure printing, and to a method of producing the same.

In accordance with the present invention, an

intaglio printing surface is produced by means of half-tone screen photography, and, with the exception of certain manipulations in photography, standard photo-engraving methods and equipment are used resulting in a simpler, cheaper, and

surer method of producing an intaglio printing surface as distinguished from the present carbon tissue process. In this latter process, the etched cells or recesses which constitute the printing areas of the intaglio surface are equal in size and render the various tonal efiects by reason of' their varying depth, the deepest cells printing the solids or darkest color, and the most shallow cells the lightest tints. In contrast therewith, the intaglio printing surface of the instant invention derives its tonal effect from the fact that the recesses constituting the printing areas vary in size, from the largest representing the solids to the smallest representing the lightest tones. The invention is further characterized by the fact that the portions of the intaglio surface which print the solids or black portions have a suificient resist in the form of upstanding walls to support the doctor blade during the inking process.

In accordance with the invention, a film or negative is exposed to the design to be repro-' duced through a halftone screen, using a round or square diaphragm. This exposure produces a series of dots on the negative in the regions corresponding to the highlights, while the regions corresponding to the shadows are but slightly affected. The size of the dots are proportional to the amount of light reflected from the object;'and where the amount of light is large the dots will partially overlap. The negative is then subjected to a second exposure through a half-tone screen but this time with a slotted diaphragm, and the design is replaced by suitable means for producing light of uniform intensity, such as a plain white surface 45 or other surface having high reflecting properties. This exposure is of comparative short duration and produces a series of lines in the region of the negative corresponding to the shaded portion of the original design; that is the region of 50 the negative which was but slightly affected during the first exposure. The second exposure has no efiect upon the regions corresponding to the highlights of the object, as this region was completely exposed in the first instance. 55 The negative is then developed, a positive made therefrom by contact, and a metal print obtained by contact with the positive. In the positive, the exposed and unexposed portions correspond respectively with the unexposed and exposed portions of the negative. Thus, the portions of the positive corresponding to the highlights of the design, and which in the negative was characterized by the fact that the dots had partially merged, will be unexposed except in the portions between the dots, as will also the portions corresponding to the lines of the negative. The resulting positive when developed will have a series of dots in thehighlights and a series of lines in the shadows, the dots corresponding to the portions between the dots of the negative and the lines corresponding to the portions between the lines of the negative.

This positive is then used to make a metal print on the printing element by first coating the element with a light sensitive material, as for instance, sensitized asphaltum, and thereafter exposing the element to light through the positive which, for this purpose, is placed in contact with the light sensitive surface. The sensitized asphaltum becomes fixed or insoluble in those regions affected by the light, so that when the member is developed and etched an intaglio design results depending for its tonal effect upon the printing areas of the recesses.

Referring to the drawings:

Fig. 1 illustrates the design to be transferred to the printing member;

Fig. 2 illustrates the negative after the first exposure; V

Fig. 3 illustrates the negative after the second exposure;

Fig. 4 illustrates the positive made from the negative shown in Fig. 3;

Fig. 5 is a diagrammatic view, illustrating the means'employed in making the first exposure of the negative;

Fig. 6 isa diagrammatic view, illustrating the means employed in making the second exposure of the negative;

Fig. 7 is a diagrammatic view, illustrating the method of transferring the design from the positive to the printing member; and

Fig. 8 is a cross sectional view through a printing member, illustrating the raised wall portions in the deeply etched regions thereof.

Referring to Fig. 1, it will be observed that the design selected for illustration is a cube having a highlight portion A, an intermediate shaded portion B, and a region of deep shadows or solids C. A film or plate D is then exposed to the design through a half-tone screen E and a diaphragm F provided with a round or square aperture F The design is properly illuminated by means not shown, and the exposure is of sufficient duration to produce an effect on the negative such as illustrated in Fig. 2. It will be observed that this step produces a result similar to that found in the usual half-tone process, namely, the negative will have a series of dots in the different regions proportional in size to the amount of light reflected from corresponding regions of the design. Thus, in the portion of the negative A corresponding to the highlights of the object, the dots a will be very large, and in fact will overlap so as to leave small unexposed portions a between the dots.

In the region B of the negative corresponding to the intermediate shaded portion B of the design, the dots b produced are smaller than those in the region A and, depending upon the depth of the shadow, will have correspondingly larger unexposed areas b between the dots.

The region C of the negative, corresponding to the region of deep shadow C of the design, will be affected but slightly, due to the small amount of light reflected from this portion of the object, and at the most will have a series of very small dots c and a correspondingly large unexposed area 0 between the dots.

Without removing from the camera, the negative D is exposed a second time through the halftone screen E, but for this exposure the object is replaced by means for producing substantially uniform light impressions over the entire surface of the negative, such means for example being a uniformly reflecting surface, as a white screen H uniformly illuminated by means not shown. Also for this exposure, the diaphragm J, employed, has an elongated slot J The effect of this exposure is to produce a series of parallel lines on the negative which, if it were not for the previous exposure, would cover the entire area of the negative uniformly. The line effect is produced by so regulating the length of exposure that the long narrow images on the negative resulting from the-use of the slotted diaphragm, merge lengthwise.

The negative D, after the second exposure, is illustrated'in Fig. 3. Herein it will be observed that the second exposure has had no effect upon the region A for substantially all of this region was exposed in the first instance. The region B however, does show the effect of the second exposure somewhat, the lines b appearing as passing through the dots b. This effect is due to the fact that the dots b are not sufiiciently large to merge, but still greater in diameter than the width of the lines.

In the region C a series of parallel lines :2 will appear, extending through the lines of dots c and will substantially obliterate the same due to their small size. In this region a substantially large portion of the region c between the lines will remain unexposed.

The next step in the process comprises making a positive K from the doubly exposed negative D. This may be done in any well known manner, as by exposing a sensitive film to light passing through the negative. The positive K thus produced (see Fig. 4) has a series of small opaque dots kin the region K of the highlights, the dots corresponding to the unexposed portions 0. of the negative, and the transparent area k between the dots corresponding to the area occupied by the large dots a on the negative. Likewise in the region of intermediate shadow K and deep shadow K the resulting design will be the converse of what appeared on the doubly exposed negative, that is, a series of opaque lines or exposed portions k, k will appear, interspaced by transparent lines or unexposed portions R R The design of the positive is transferred to a printing member M having its surface previously prepared by coating with a light sensitive substance, such as sensitive asphaltum. The exposure is preferably made by placing the positive K in close contact with the surface of the printing element and subjecting the latter to a suitable light source L (Fig. 7). The asphaltum is rendered insoluble wherever it is aifected by light, while the portions unafifected by light remain soluble. When the printing member M is washed or developed, the soluble asphaltum is dissolved, exposing portions of the surface thereof, while the rest of the surface remains covered with the insoluble asphaltum which acts as a resist to the etching fluid.

The developed printing member M is placed in the etching bath and the portions, from which the asphaltum has been removed, etched to produced an intaglio design. Thus, the regions of the member corresponding to the high lights are etched with a series of small dots corresponding to the opaque dots of the positive, but by far the larger portion of this area is protected by the asphaltum. A considerably larger area of the intermediate shadow region is etched, but in this area there, still will be a comparatively large portion remaining unetched to support the doctor blade during printing.

The region of deep shadows or solids is etched to the greatest extent, since this portion of the printing member has the largest surface area exposed to the etching fluid, and if the portions of this region, protected by the asphaltum, were of a size corresponding to the Small dots c of the negative after its first exposure, sumcient resist would not be presented to support the doctor blade.

However, due to the parallel transparent portions k between the lines'k on the positive in this region, the printing member will have a corresponding series of parallel portions covered with asphaltum, and when the printing member is etched, these portions will be left as a series of upstanding parallel walls M having their upper edges M flush with the outermost surface M of the printing member, the intermediate spaces M of course, being etched to receive the printing ink. The walls M thus resulting render the necessary support or resist for the doctor blade during inking.

The order of exposing the negative may be reversed, if desired, and the same results obtained, 1. e., the negative may first be exposed through a half-tone screen and a slotted diaphragm to a source of substantially uniform light and thereafter to the image or subject through the half= tone screen, the order of exposure being left to the convenience of the operator.

In other words, the invention in its broadest aspect provides an intaglio printing element made by means of half-tone screen photography, and which is formed with a series of thin upstanding walls acting as a support for the doctor blade in those portions of the element adapted to print solids, thus distinguishing from an intagiio printing element obtained by normal half-tone screen photography, which would be provided only with a series of minute upstanding dots in the portions adapted to print solid. Such dots would furnish insuficientsupport for the doctor blade, and would shear 0E, or at least wear rapidly, thus allowing the doctor blade to remove the ink from the portions of the printing element representing the solids.

Where a photographic film has been referred to throughout the specification and claims, it is to be understood to include a photographic plate as well or any other photographic element that can be used for the purpose.v Likewise, where a printing member has been referred to, this includes not only a fiat printing plate, but also printing cylinders such as those used in rotogravure printing, as well as any other type of printing member which may be satisfactorily employed for photogravure work.

Furthermore, it will be understood that many changes may be made in carrying out the process of the invention which however, will still be included within its spirit. The invention, therefore, is to be limited only by the prior art and the scope of the appended claims.

Having thus described my invention, what I claim is:

1. The method of preparing an intaglio printing surface, which comprises'exposlng a film to the object to be reproduced through a half-tone screen and through a diaphragm to produce a series of dots in certain portions of the film, exposing a film a second time to light having uniform intensity and through a half-tone screen and a diaphragm of a character 'to produce a series of lines in the portions of the film left unexposed in the first instance, making a positive,

from saidfilm, and preparing from the positive, a resist through which a metallic member is etched to produce the intaglio printing surface.

2. The method of preparing an intaglio printing surface, which comprises exposing a film to the object to be reproduced through a half-tone screen and through a diaphragm to produce a series of dots 'on the film, proportional in size to the amount of light reflected from corresponding regions of the object, exposing the film a second time through a half-tone screen and through a slotted diaphragm to light having uniform intensity, to produce a series of lines in the portions of the film but slightly affected by the first exposure, making a. positive from said film, and preparing from the positive, a resist through which a metallic member is etched to produce the intaglio printing surface. I

3. The method of preparing an intaglio printing surface, which comprises exposing a film to the object to be reproduced through a half-tone screen and with a diaphragm to produce a series of dots in certain portions of the film correspond ing to the highlights of the object to which the film is exposed, thereafter exposing the film through a half-tone screen and a slotted diaphragm to produce a series of lines in the portions of the film corresponding to the shadows of the object, making a positive from said film, and preparing from the positive, a resist through which a metallic member is etched to produce the intaglio printing surface.

4. The method of preparing an intaglio printing surface, which comprises exposing a film to the object to be reproduced through a half-tone screen and with a diaphragm to produce a series of dots in certain portions of the film corresponding to thehighlights of the object to which the film is exposed, thereafter exposing the film through a half-tone screen and a slotted diaphragm to light having uniform intensity to produceaseriesv of lines-in the portions of the film corresponding to the shadows of the object, making a positive from said film, and preparing from the positive, a resist through which a metallic member is etched to produce the intaglio printing surface.

5. The method of preparing an intaglio printing member having. a series of upstanding wallsto support a doctor blade in the portions that print solid, which comprises, preparing a negative by exposing a photographic film or plate to an object through a half-tone screen to produce a series of dots in the portions ofv the film corresponding to the highlights, exposing the film a second time through a half-tone screen to light having uniform intensity and through a diaphragm of a character to produce lines on the film in the regions substantially unaflected by the first exposure, making a positive-of the. film thus exposed, and preparing from the positive, a resist through which a metallic member is etched;

6. The method of preparing an intaglio printing member having its intaglio surface adapted to print different tonal efiects, which comprises preparing a negative of the subject having a series of opaque lines in that portion of the negative corresponding to the solids of the subject, and which includes an exposure of the negative through a half-tone screen and a slotted diaphragm, making a positive from the negative, and preparing from the positive, a resist through which a metallic member is etched to produce the intaglio printing surface.

7. The method of preparing an'intaglioprinting member having its intaglio surface adapted to print difl'erent tonal effects, which comprises preparing a negative of the subject having a series of opaque lines in thatportion of the negative corresponding to the solids of the subject, and which includes exposing the negative to the subject to be reproduced through a half-tone screen and also to a source of substantially uniform light through a half-tone screen and through a diaphragm adapted to produce said lines in the portions of the negative corresponding to the solids of the subject, making a positive from the negative, and preparing from the posi-- tive, a resist through which a metallic member is etched to produce the intaglio printingsurface.

8. The method of preparing an intaglio printing member having its intaglio surface adapted to print difl'erent tonal effects, which comprises preparing a negative of the subject having a series of opaque lines in that portion of the negative corresponding to the solids of the subject, and which includes exposing the negative to the subject to be reproduced through a half-tone screen and also to a source of substantially uniform light through a half-tone screen and a slotted diaphragm, making a positive from the negative, and

' preparing from the positive, a resist through which a metallic member is etched to produce the intaglio printing surface.

9. The method of preparing an intaglio printing member having its intaglio surface adapted to print difl'erent tonal effects, which comprises preparing a negative of the subject to be reproduced having a series of dots in the portions of the negative representing the lighter tones, and a series of lines in the portions representing the solids, and which includes an exposure of the negative through a half-tone screen and a slotted diaphragm, making a positive from the negative,

. and preparing from the positive, a resist through which a metallic member is etched to produce the intaglio printing surface.

10. The method of preparing an intaglio printing member having its intaglio surface adapted to print difierent tonal effects, which comprises preparing a negative of the subject to be reproduced having a series of dots in the portions of the negative representing the lighter tones, and a series of lines in the portions representing the solids, and which includes the steps of exposing the negative to the subject through a half-tone screen and to a source of substantially uniform light through a half-tone screen and a slotted diaphragm, making a positive from the negative, and preparing from the positive, a resist through which a metallic member is etched to produce the intaglio printing surface.

11. The method of preparing an intaglio printing member having a series of upstanding walls to support'a doctor blade in the portions that print solid, which comprises preparing a negative by exposing a photographic film or plate to an object through a half tone screen to produce a series of dots in the portions of the film corresponding to the high lights, giving the film an additional exposure through a half tone screen and through a diaphragm of a character to produce lines on the film in the regions previously substantially unaffected, making a positive of the film thus exposed and preparing from the positive, a resist through which a metallic member is etched.

12. An etched intaglio printing element having a screened surface adapted to reproduce by printing'the difierent tonal effects of a subject, said screened surface being formed with ink retaining wells of substantially the same depth and of varying printing area, said wells varying in area from the largest in those regions adapted afioaaae to print the solids of the subject to the smaliest in those regions adapted to print the lightest tones, and wherein the ink retaining wells in at least certain of the portions other than those adapted to print the solids are uniform as to shape and arranged according to a geometric pattern, and the ink retaining wells in those portions adapted to print the solids being defined by upstanding wall portions. all of which are straight throughout their entire length and of uniform width, and said wall portions having their top edges at substantially the same level as the non printing surface of the printing element so as to act as doctor blade supports.

13. An etched intaglio printing element having a screened surface adapted to reproduce by printing the different tonal effects of a subject, said screened surface being formed with inlr retaining wells of substantially the same depth and of vary-=- ing printing area, said wells varying in area from the largest in those regions adapted to print the solids of the subject to the smallest in those regions adapted to print the lightest tones, and

wherein the ink retaining wells in at least cer- I 1W N. IiHSUI-ZACA.

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