US2178118A - Method of producing bleed line by diffusion of light - Google Patents

Description

Patented oef. 31, 1939 UNITED STATES METHOD F PBODUCING BLEED LINE BY DIFFUSION 0F LIGHT Owen R. Huggins, South Norwalk, Conn., as- I signor to Linotone Corporation, -a corporation of New York Application December 21, 1938, Serial No. 246,951

y 6 claims. This invention relates to the production of printing surfaces. and it is concerned more parl ticularly with the production of printing surfaces by photography. i

In accordance wth a method already proposed.

L". is placed in contact with one face of a screen and a second light sensitive lm or plate is placed in contact with the other face of the screen. The negative is subjected to the action ci light to create on the second light sensitive lni or plate a marginally reduced screened reproduction ofthe design element. Thereafter,

the original positive is placed in exact register with the marginally reduced screened reproduction on theundeveloped lm or plate and subelement having screen lines which fall short of the outline thereof. The lm or-plate is then developed, and the negative thus obtained is employed in a well-known manner to create on a printing member an etched full size reproduction of the design element whereinthe ground lines fall short of the boundry or outline to form a so-called bleed line.

' While the above described method of reproducing a given design element on a printing member is satisfactory in many respects, it is open to the objection that since the element is reproduced in full size adjacent printed reproductions tend t run together or ilush, this being particularly true when the reproductions are printed on textiles and the like.

- 'I'he primary purpose of the present invention is to provide a photo-mechanical method of reproducing a design elementen a printing memberl in such a manner that the reproductionis reduced marginally a distance suiliclent to prevent the color from adjacent printed impressions from running together or ilushing, and the ground 5o lines fall short of the boundary or outline of the reproduction to establish a bleed line.

vFor a complete description as to how the improved process is carried out reference may be made tothe .accompanying drawing wherein the design is shown, by way of example, as being jected to the action of light to create on the filmor plate a full size reproduction of the design (ci. 95-5) ,u

circular in form. It is to be understood, however, that the invention is not limited to the production of this particular design on a printing mem ber, but is applicable as well to the production of other designs of different forms.

Referring to the drawing-f Fig. 1 is a plan view illustrating a the design element;

Fig. 2 is a diagrammatic view showing the positive spaced from a light sensitive member and having a source of light directed `against it;

Fig. 3 is a plan view illustrating a marginally reduced negative of the design element;

Fig. 4 is a diagrammatic view showing the mar; `ginally reduced negative, an interposed screen, a light sensitive member, and a source of light directed against the'negative;

Fig. 5 is a plan view of the marginally reduced screened reproduction obtained on the light sensitive member shown in Fig. 4 when the negative is subjected to the action of light;

Fig. 6 is a diagrammatic view showing the positive of Fig. 1 spaced from the marginally reduced screened reproduction shown in Fig. 4 and'with apositive gfsource of light directed against it, the spacing in this arrangement being less than the spacing in the arrangement shown in Fig. 2;

Fig. l is a plan view showing the negative obtained after the light sensitive member shown in'lFig. 6 has been developed; and

Fig. 8 is a plan view of the positive obtained by contact with the negative shown in Fig. 7

In practicing the present invention, a positive I0 comprising' an opaque.reproduction Il of a' given design element is created on a light transparent plate I 2 either by hand or by photography (Fig: 1) A transparent member I3 having a predetermined thickness is interposed between the positive I0 and a light sensitive member I4, and light from any suitable source is directed against the positive I0 (Fig. 2). The reproduction II of the design element on the positive Iii, being opaque, prevents the passage of light and, as a result a reproduction I5 of the design element on the light sensitive member I4 remains unaiected by light, but the remaining exposed por- 1" tion I6 of the member becomes affected by the light vwhich passes through the transparent portion of the positive I0 and through the interposed transparent member I3. During this exposure of the light sensitive member Il, however, the light is so directed against the positive I0 that the rays converge inwardly from the outline or boundary of the opaque reproduction II as they pass through the positive I0 and the intervening respondingly less distance.

member I3. In consequence, the light unaiected reproduction I5 of the design element on the light sensitive member I4 is reduced marginally a distance determined by the convergence of the light rays.

After the marginally,reduced reproduction I5 has been so created, the light sensitive member I4 is developed to render the reproduction I5 transparent andthe light affected portion I5 opaque.

. Thereafter, a screen I 'I is interposed between the developed member or negative I 4 and a second light sensitive member I8, and light is directed against the negative, preferably perpendicularly thereto (Fig. 4). The marginally reduced reproduction I5, being transparent, permits the passage of light but the remaining portion I 6 of the negative, being opaque, prevents the passage of light during this exposure of the second light sensitive member I8. The light which passes through the transparent reproduction .I5 also passes through the transparent portions of the screen onto the member I8, and, as a result, a Amarginally reduced screened reproduction 20 of the design element comprising a number of spaced light affected lines 2I is created gn the member I8as shown by dotted lines in A second transparent member 22 of less thickness than the transparent member I3 employed to create the first marginally reduced reproduction I5 is now interposed between the positive Ill and the still undeveloped light sensitive member I8 and the opaque reproduction II is centered with respect to the screened reproduction 20 (Fig. 6). Then the source of light is so directed against the positive I0 that the rays converge inwardly at substantially the same angle that they did during the creation of the first marginally reduced reproduction I5. As in the previous case, the reproduction II, being opaque, prevents the passage of light and, as a result, a reproduction 23 of the design element on the member is shielded against the action of light while the remaining exposed portion 2.4 vof the undeveloped member I8 becomes aii'ected by the light which passes through the transparent portion of the positive I0 and through the transparent member 22.

, The reproduction 23 on the undeveloped member 50 I8 so shielded, however, is reduced marginally a distance determined by the convergence of the light rays as they pass through the-transparent member 22, and since this member is thinner than the member I3 employed in the creation of the rst marginally reduced reproduction I5, the` reproduction 23 is reduced marginally -a corrender transparent the light unaiected portions of the reproduction 23. The developed member or negative. I8, as sliown in" Fig. 7, comprises a transparent marginally reduced reproduction 23 ofthe design element having a number of opaque lines 2| whichvfall s hort of the outline or bonndary thereof.

A contact positive (Fig. 8) may now be* made from the negative I8 and thereafter placed in Furthermore, since s intimate contact with a light sensitive coating on a printing member and subjected to the action of light, the member treated to develop the coating, washed to remove the unaiected portions of the coating, and subjected to the action of an etching acid. The resultant etched reproduction of the design element is reduced` marginally and it is provided with a plurality of spaced ground lines which fall short-of the boundary or the outline of the reproduction and so provide a bleed line.

By properly regulating thel distance that the etched reproduction is reduced marginally and by so providing a bleed line into which empty the color carrying grooves between the ground lines, printed reproductions of a given design element may be obtained which are satisfactory in every detail.

Having thus described my invention, what I claim is: n

1. In the .art of producing printing surfaces, a process which consists in creating a positive of a design element, creating a negative of said positive reduced marginally a predetermined distance, exposing a light sensitive member to the action of light projected through said negative and a screen to create thereon a screened reproduction of the negative, spacing said member from said positive with the screened reproduction centered with respect thereto, exposing said member to the action of .light projected through said positive which is so spaced therefrom that a tance, exposing a light sensitive member tothe action of light projected through said negative and a screen to create thereon a screened reproduction of the negative, interposing a transparent member between said light sensitive member and said positive with the screened reproduction centered with respect to the positive, exposing the light sensitive member to the action of light projected through said positive which is so spaced .therefrom by the transparent member that a reproduction of the design element reduced marginally a distance less than said predetermined distance is shielded against the action during exposure, and then developing the exposed member.

3. In the art of producing printing surfaces, a

process which consists in creating a positive comprising an opaque reproduction of a design element on a transparent plate, spacing said positive from a light sensitive member, exposing said member to the action of light projected through said positive which is Iso spaced therefrom that a reproduction of the design element reduced Amarginally a predetermined distance remains duction thereon of the design element reduced marginally a distance less than said predetermined distance remains unaiected by light, and developing said second member.

fi. In the art of producing printing surfaces, a process which consists in creating a positive comprising an opaque reproduction of a design element on a transparent plate, interposing a transparent member between said positive and a light sensitive member, exposing said member to the action of light projected through said positive and said transparent member, developing said sensitized member to create a marginally reduced negative of said design element, exposing a second light sensitive member to the action of light projected through said developed member and a screen to create thereon a marginally reduced screened reproduction of 'the design element, interposing a transparent member thinner than said rst mentioned transparent member between said positive and said second light sensitive member with the .screened reproduction centered with respect to the opaque reproduction, exposing said second light sensitive member to the action of light projected through said positive and said second mentioned transparent member, and developing the second light sensitive member to create a marginally reduced 'reproduction 'of the design ,element having screen lines which fall short ofthe outline of the reproduction.

5. In the art of producing printing surfaces, a process which consists in creating a positive comprising an opaque reproduction of a design element on a transparent plate, interposing a transparent member between said positive and a light sensitive member, exposing said light sensitive member to the action of light projected through said positive and said transparent member, developing said sensitized member to create a marginally reduced negative of said design element, interposing a screen between said negative and a second light sensitive member, exposing said second licht sensitive member to the action of light projected through said negative and said screen to create thereon a marginally reduced screened reproduction of the design element, interposing a transparent member thinner than said first mentioned transparent member between said positive and said second light sensitive member with the screened reproduction centered with respect to the opaque reproduction, exposing said second light sensitive member to the action of light projected through said positive and said second mentioned transparent member, and developing the second light sensitive member to create a marginally reduced reproduction of the design element-having screen lines which fall short of the outline of the reproduction.

6. In the art of producing printing surfaces, a process which consists in creating a positive comprising an opaque reproduction of a design element on a transparent plate, interposing a transparent member between said positive and a light sensitive member, exposing said light sensitive member to the action of light projected at an angle through said positive and said transparent member, developing said sensitized member to create a marginally reduced negative of said design element, interposing a screen between said negative and a second light sensitive member, exposing said second light sensitive member to the action of light projected through said negative the action of light projected at an angle through said positive and said second mentioned transparent member to create a marginally reduced reproduction of the design element having screened lines which fall short of the outline of the reproduction.

o OWEN R. HUGGINS.

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