DE2410287A1 - IMPROVED TESTING PROCEDURE OF COLOR DRAWINGS WITH COLOR TESTING FILMS AND TESTING SYSTEM FOR IT - Google Patents

Description

K 23.13A FP-Or.?,-is 1- War2 1974

description
to register the

AMERICAN HOECHST CORP.

Bridgswater, New Jersey,

UNITED STATES.

for a patent
concerning

Improved test procedure for color separations with color test films and test system for them

The present invention relates to the photomechanical production of images on various substrates and relates in particular to the photomechanical production of multicolor images, especially for the purpose of checking color separation negatives or positives.

With multi-color printing, at least three colors are used, known specifically as magenta, yellow, and cyan. In many cases one uses and to increase depth Also fill in black as the fourth color. A printing element is required for each color.

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To produce the three or four printing elements, provide you can produce three or four color separations by making the original slide using suitable color correction templates and light filters photographed. Since printing is usually a "raster" process, one uses also a suitable "grid" to form a "grid" negative or positive. The production of the color separations requires considerable skill and does not succeed always on the first try. Correction or replacement of one or more color separations may therefore be necessary. It it will be understood that, where possible, it is desirable not to make the costly printing element itself and to set up a printing press to use to print to check the statements, but a cheaper and faster one Procedure to choose. One such method for color testing of color separations is the "superimposing" method, another is the "transfer" method. The invention described here represents one which can be used for both methods Improvement.

Overlay processes are described in U.S. Patent 3,136,637 issued June 9, 1964 to GW Larson and U.S. Patent 3,326 issued June 20, 1967 by Fritz Endermann. With this technique

retroactively
changed

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you have a light-sensitive transparent film for each of the colors to be printed with the correct one Color, for example with a dye or pigment, combined with a light-sensitive reagent is. Each of the foils is exposed through its respective screened color separation. The color in the non-image areas is removed, resulting in a film that contains the desired color pattern in the image areas, while it remains transparent in the non-image areas. After the production of each of the individual foils, these are precisely registered on an opaque, usually white, Brought together underground, after which a color separation of the original is obtained.

The overlay process just described is a long one spread. While it has many advantages, it also has several disadvantages of its own, primarily the result is that a plurality of layers, usually four, are required to produce the test sheet. It is an object of the present invention to remedy some of the major deficiencies in the overlay process.

The first shortcoming of a stacking system is that the carrier film, even if it is of the best,

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is commercially available quality, is measurable gray and cloudy »with each layer adding about 0.06 to 0.07 to the reflection density of the base. Since four foils are used *, these can add a total of 0.28 density units to the specified reflection density. Since a density of 0.30 means that only half of the light is reflected, the combination of grayness and cloudiness leads to a considerable difference between the test film and the original or final print.

The second shortcoming of a stacking system is the loss of light and contrast due to multiple reflections between the carrier film and between the upper one and lower surface of each carrier sheet. This also worsens the picture.

The third flaw in a stacking system is as big as the first two, but more subtle. The problem is that halftone coloring in a superimposed system increase in density, although the actual point size can be reproduced exactly. This results from the fact that each color in the superimposing system is on a separate carrier of a certain thickness, and thus the individual

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Color images, when they are brought together in perfect register, each have a different distance from the reflective surface. Places of the reflective base between grid points, which should appear in the color of the base, are colored by the light that has penetrated at an angle through the grid points. Therefore, when viewed with the eye, the entire color of a halftone color consists of a mixture of each halftone dot and the color between the dots. This effect causes the pitch stains darker than one would expect from their point size, and graphic (plate manufacturer or printer) must the test film "interpret" to predict from their appearance to how the final pressure will be.

The object of the present invention is to remedy the above mentioned shortcomings of the superimposing system, i.e. the neutral Density increase, the multiple reflections and the color distortion to reduce significantly. The solution to the task is' characterized in that one of the carrier foils is switched off by applying a color directly to an opaque, generally white, applies a carrier, which is intended to also serve as a base for the other colors to serve. The improvements, each in the order of magnitude

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a quarter or a third, depending on whether a three- or four-color test film is being made, have a cumulative effect that is quite evident when using the stacking test sheet of the present invention compares to the state of the art. In particular, the sharpness and luster of the color are improved to a surprising degree, that exceeds expectations.

The carrier receiving the color images is expediently usually white, but can be any within the scope of the invention have any color or, for example, have a metallic surface, so that it matches the material on which the Should be printed at the end, can be similar.

The overlay test system of the present invention retains the advantages of the overlay test films and shows significant improvements. After a precisely fitting arrangement and honing, the assembled sample easily disassembled, e.g. to analyze a single color or a combination of colors. The handling and implementation of the system of the present invention are exactly as in the case where all Colors are on a transparent base. The colors can still be exposed at the same time, resulting in a

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Significant time savings compared to test systems, which have to be exposed one after the other.

We have found that the most suitable paint for coating on the opaque, white substrate Is magenta. However, any of the other colors could also be applied to the opaque, white background which would also result in the advantages listed for this system. If you use the order in If magenta is first applied, then magenta does not have to be applied first in the printing sequence, since it it is well known that the printed printing inks do not combine in any way like an overlapping test film, As a result, the user can select the check order regardless of the print order.

In the preceding discussion, reference is sometimes made to screening techniques. It is clear, however, that continuous halftone printing does not use a screen. the The present invention relates to raster and non-raster printing. However, most, but not all of the claimed benefits also apply to continuous half-tone printing, especially with regard to increased sharpness and reduced gray content.

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The applicability of the present invention is independent of the particular application for the preparation of the photosensitive element and the resulting images compositions used. So she can with the negative working compositions of Larsons U.S. Patent 3,136,637, referred to above, may be used where a soluble, photosensitive diazo resin is first coated on a carrier sheet and coated with a polyvinyl formal resin containing a colored pigment. It can also be used for photopolymer layers, which are typically a Ethylenically unsaturated monomer, an addition polymerization initiator that is produced by actinic radiation can be activated, contain a dye or a pigment and an organic, polymeric binder. she can also be used for the positive working diazo bases of U.S. Patent 3,326,682 to Fritz Endermann to provide another example as well as for electrostatically imaged layers on transparent substrates.

The transfer method of color proof is the second important method to which the present invention is referred to Improvement can be applied. A review

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method is disclosed in U.S. Patent 3,671,326 to P.C. Van Buesekom described. With "this technique has one a photosensitive layer of each of the to be printed Colors on separate transfer foils. The transfer foil can be the same as the transparent film in the superimposing process or a thinner, cheaper foil, and the color coating material can also be the same as in the superimposing process. The paint layer is covered with an adhesive, which can be either self-adhesive or heat-adhesive. The film so coated is then applied to an opaque, generally white receiving film, and the color layer is transferred to the recording sheet. The recording sheet is then exposed through the corresponding screened negative color separation, and the color at the non-images is removed. After that, each will the other layers of color transferred one after the other onto the same recording sheet and worked until three or more four layers are applied in this way. The great advantage of the transfer test method is that it is almost complete Eliminating the previously listed defects of the one on top of the other leg test.

A major disadvantage of the method of transmission is that

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2U0287

that the entire processing must take place one after the other, while using the overlay method for everyone Layers can be done simultaneously.

When the present invention is applied to the transfer process, the recording sheet with the first coat of paint, eliminating a transfer step and the laboratory time required for it which can lead to considerable savings in the case of large-scale production of test films.

As with the overlay method, the applicability is of the present invention is also not limited chemically or physically to a particular image formation. Consequently can use the system of the aforementioned Van Beusekom (U.S. Patent 3,671,236) using photosensitive Diazo compounds benefit from the present invention as well as those on photopolymers based transmission system.

The practice of the present invention and the advantages resulting therefrom are described in the following Example described.

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example Experiment 1 (state of the art)

a) Production of a blue film image

A cyan coating solution was made by adding 4.5 g of a condensation product of 3-methoxy-diphenylamine-4-diazonium sulfate and 4,4'-dimethyldiphenyl ether, 4.2 g of Victoriareinblau FGA and 20.0 g Vinyl acrylic terpolymer latex (X-Link 2813, manufacturer National Starch) in a mixture of 20 ml of methyl alcohol, 100 ml of methyl isobutyi ketone., 300 ml of diacetone alcohol and 580 ml

Dissolved methyl ethyl ketone. The solution was to a 0.0075 mm thick polyethylene terephthalate film applied using a meniscus coater. The required layer weight depends on the desired color density. The layer was dried in an oven.

The slide was screened through a conventional Farbauszugnegatiν exposed, using as a light source Use a 2,500 watt NuArc FT 40 AM light unit for 2 minutes at a distance of about 60 cm became. The non-image areas were washed with an aqueous Removed developer solution containing 10.0% by weight sodium noctyl sulfate and 3.0% by weight trisodium phosphate. The film was then rinsed with water and dried.

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b) Production of a yellow F & If enb fides

It was produced a yellow BeschicftturtgsTSscmg * mart by 18.0 g of Df azo compound of; Preparation a} 10.0 g Grasolechtgelb 3 GL and 20 * 0 g Wfftylacrylterpolyraerlatex from preparation a} in a mixture of 400 ml methyl cellosolve (ethyl englykalntonomethy 1 ether), 150 ml methyl alcohol and 450 ml ethyl ethy ketone. The solution was used to make a yellow film using the procedure outlined in Preparation aj. The film was exposed under a yellow screened printing element and then developed.

c) Production of a black film image

A black coating solution was made by adding 30.0 g of the diazo compound from preparation a), 30.0 g of fuel black No. 3 and 20.0 grams of vinyl acrylic terpolymer latex from preparation a) in 300 ml methyl cellosolve, 200 ml of ethyl alcohol, 250 ml of methyl alcohol and 250 ml Methyl ethyl ketone dissolved. The solution was described for the production of the black film as in production a) used. The film was exposed under a screened black printing element and then developed.

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d) Herste! lm§ Elmes red foil ienbi Ides

There was prepared a magenta ßeschichtungslösung by 14 ₉ 0 g of the diazo compound of Preparation A), 12.0 g Grasolectitrufoin 2 BL and 20.0 g Vinylacrylterpolymerlatex of manufacturing a) in a mixture of 250 ml of diacetone alcohol, 100 ml of methyl Cellosolve, 100 ml of methyl isobutyl ketone, 150 ml of methyl alcohol and 400 ml of methyl ethyl ketone dissolved. The solution was used to produce a magenta film as described in preparation a). The film was exposed under a screened magenta printing element and then developed.

The four color picture layers from fabrications a) - d) were placed one on top of the other in register and brought into contact with a white reflective support. So it became get a color reproduction. This is the common method of putting four coated transparent films on one reflective supports can be used.

Experiment 2 (invention)

A magenta layer was applied directly to a white opaque film. For this purpose and for one

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To have correct color balance in the final test film, the magenta coating of the previous production d) was modified. A solution of 0.4 g the diazo compound from preparation a), 0.4 g Grasolechtrubin 2 BL and 1.0 g vinyl acrylic terpolymer latex from Preparation a) in a mixture of 30 ml of diacetone alcohol, 15 ml of methyl alcohol and 55 ml of methyl ethyl ketone dissolved. The solution then turned opaque to a white Polyethylene plastic film (called "Arco Art" and from Mead Papers available). Exposure and development were the same as in manufacture d) described.

The films from preparations a), b) and c) with yellow, blue and black images were brought into register in the specified order with the red stomach image, which was applied to the white, opaque base.

The superimposed test film made of three image films that are superimposed over the opaque white coated with magenta, was side by side with the conventional color proofing film of preparations a) to d), the was made from the same color separation negatives in one

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Color matching booth compared with 5,000 ⁰ K color temperature. The three-layer test film of this example had a sharper image than the conventional four-layer test film. Furthermore, areas between grid points of the four-layer test film, which should appear white, were colored. With the three-layer test film of the present invention, less false color had fallen into the white background between the dots. Also, the substrate of the three-layer test film of the present invention was less gray than the four-layer test film. I.

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Claims (8)

Claims 1. Multicolor test method, characterized in that a layer of the desired image in one of the Colors is formed on an opaque support and then successively a layer of the desired Image in each of the other colors is applied in register on said opaque carrier. 2. The method oach claim 1, characterized in that that one forms the image in each of the other colors on separate transparent sheets and the transparent sheets brings them into register with one another and with the opaque carrier. 3. The method according to claim 2, characterized in that a photosensitive layer of suitable color the transparent film is applied, the transparent film being exposed through its respective color separation and removing the paint in certain areas on the transparent sheet to produce the desired image. 4. Process according to Claims 1 to 3, characterized in that that one uses an opaque support which is white and forms on it the red color separation image. 409837/0839 5. multicolor testing system, characterized in that it from an opaque carrier with one on it formed layer of a desired image in one color and a plurality of desired superimposed in register Images in the other colors is formed. 6. System according to claim 5, characterized in that the images of the other colors are each on a separate FoI ie applied and the transparent foils are superimposed on the opaque carrier, 7. System according to claim 5 or 6, characterized in that the opaque carrier white and that The color separation image formed on it is red. 8. Multicolor test method, in which one is with Transparent foils provided with color separation images superimposed in precise register, characterized in that the color separation image below is on an opaque carrier. 409837/0839