DE2020069A1 - Photographic process for making images - Google Patents

Description

Photographic8 methods of producing images

The invention relates to a photographic method of manufacture of images »those from points available in different numbers and statistically random distribution They are made up by exposure and development of a photographic recording material.

In the field of photographic reproduction, in particular of lithographic reproduction, as is well known, considerable advances have been made recently, which has led to daee the need for in simple and economical Ways to be carried out procedures for the production of qualitative special high-quality images constantly rose. The quality assessment Such images are mainly based on the reference point, to what extent fine details of the original image used * * are reproduced «

So read s * S # when using ron photograph! Echen recordings * at # ri * 3.ien nit silver halide as light-sensitive! Component · di · Wi «4«? $ «S # ron fine detail« dta Örlginalbildes dadurei » r * rkoe »m, daee iufeeiohnunfsmaterial mit Silber * bal © f ^ * 14icör» tr »τρη- rerflelohiweiet small part size

0 09 84 4/1202 originally inspected

Such photographic recording materials are used are characterized by an extremely high resolution and thus enable reproductions to be made in where extremely fine details of the original image can be seen. However, they are used to carry out such known procedures Line grating techniques are used, as are customary in the specified field of photography, in particular lithography are, even when using fine-grain photographic recording materials of the specified type, the Reproduction of fine details is lost.

The usable for carrying out such method consist in the grating Hegel of a network of mutually perpendicular lines ,, on a transparent substrate, Z ₀ as glass, are applied. With the help of such line grids, images with a continuously running image tone can be converted into so-called halftone images, the image tone of which runs discontinuously and which, for example, consist of a series of dots. Although such grating can be produced only in difficult and costly manner, their use is generally considered to be necessary _s to high-quality lithographic Eeproduktionen to arrive.

The use of such in grating difficulties encountered led dazuj to investigate methods for their implementation Striohgiti "he dispensable SINCL So wurde- to B ₈ some progress with the help of Tsrfahren based on. Gives images with continuous tone. Furthermore, lithographic processes which can be advantageously carried out on the basis of images of the line-tone type have been known. A disadvantage of these known processes is. however, ciaso for their implementation often only materials of a certain type _s z «B« made of materials ■ certain type consisting © printing plates ₉ usable as well as numerous © _D side. and costly process steps which have to be carefully controlled »are required,

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The object of the invention is to provide a simple and economical Way to specify a practicable method with the help of which the known halftone images without the use of line grids high quality images corresponding to the type, which are characterized by sharpness and clear reproduction of details, can be produced are ·

The invention is based on the surprising finding that the stated object can be achieved in a particularly advantageous manner in that a photographic recording material is accurate of a defined type is exposed by an original image of a precisely defined type.

The invention relates to a photographic process for the production of images, which are made in different numbers as well as statistically random distribution of existing points of different sizes exist through exposure and development a photographic recording material that thereby is characterized in that a high-contrast photographic recording material with a V value of at least about 4 exposed through a coarse-grained original image with a grain size of at least about 20 and the image-wise exposed Recording material developed.

To carry out the method of the invention, it is expedient to convert an image with a continuously running image tone into a coarse-grained image of the specified type produced, whereupon the obtained coarse-grained image as an original image to produce a image consisting of numerous hard dots arranged in the manner indicated is used. That after the procedure The image obtained from the invention and consisting of statistically randomly distributed points may at first glance appear to be Image with an image tone that runs continuously from white to light gray and dark gray to black but actually from black dots of different sizes present in different numbers. The inven-

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corresponding to images made up of points and obtained in accordance with the invention thus to a certain extent the usual, known halftone images, but differ from these insofar as than the points present in them are generated without the use of line grids as an image component and are statistically random are distributed.

To carry out the method of the invention is more advantageous Alternatively, a high-contrast photographic recording material with a "V * value" of at least about 4, preferably "of at least about 8, usable, with the help of which not only the dense areas of the original picture, but also a part the graininess of the original image, even in its high-light areas, can be recorded so that it is crisp Images with extremely high quality detail reproduction can be obtained «for carrying out the method of the invention Thus, surprisingly, the use of coarse-grain photographic images, which as a rule is qualitative are regarded as inferior as the original image for exposure of the high-contrast photographic recording materials as particularly advantageous, whereas fine-grained photographs are generally considered to be of high quality Images are not suitable for the stated purpose.

To carry out the method of the invention, coarse-grained original images can be used which have been obtained in the usual known manner (2) to measure with high development . Handle lung temperature !! images obtained j (3) camouflage iait help sound highly sensitive photographic recording material! © *! images obtained, (4) to images obtained with the help of highly active developers or (5) to images obtained by Biläyergrösseruag »It often turns out to be all two-dimensional, coarse-grained® images to be used, which are made by a combination of the specified processes, sS by developing a high sensitivity photograph! see record

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tion material can be produced in a highly active developer. Me optimal graininess dee as the original image for exposure of the high-contrast photographic recording material photographic image used depends "to some extent on the intended use of the high-contrast Image generated from recording material. It was found that an image that is subjectively referred to as grainy by the person skilled in the art Implementation of the method of the invention is usually more advantageous Way is usable. It goes without saying that it is advisable to check the graininess of the photographic material used Image and the sensitivity of the high-contrast photographic material used to each other vote in order to achieve that the grains of the image of the high-contrast immaterial recorded and after the Development can be seen in the form of dots of high density.

To carry out the method of the invention, as already mentioned, the use of a coarse-grained original image, the graininess of which under normal viewing conditions is at least about 20, preferably about 30, has proven advantageous, but it must be taken into account that the graininess of an apparently very fine-grained photograph Image can often be increased very slowly by enlarging the image with the help of conventional known methods of magnification. Although granularity is a relative term, this term is recognized by experts and understood by them as a subjective remedy for the irregularity of an image.

A variety of conventional known high contrast photographs are known to be used in practicing the process of the invention Recording materials can be used, typical such suitable high-contrast recording materials are, for example, photoconductive recording materials, the use of which can be carried out according to conventional, known standard electrophotographic methods, the exposure of which;

must be, as well as light-sensitive recording materials of the diazo type, lithographic recording materials, high-contrast recording materials containing silver halide and the same.

According to a particularly advantageous embodiment of the method According to the invention, a photographic material containing silver halide is used as a high-contrast photographic recording material Recording material, one for lithographic Photographic recording material for specific purposes, ζ, Β. a so-called "Kodalith Type III-Mlm" used, which directly, i.e., without the use of a line grating passing through a coarse-grain photographic original image Exposed to light and then in a so-called infectious developer, expediently in one for lithographic Purpose-specific developer, e.g. in a developer with the following composition:

Sodium sulfite, anhydrous 30.0 g

Paraformaldehyde 7.5 g

Sodium bisulfite 2.2g

Boric acid crystals 7.5 g

Hydroquinone 22.5 g

Potassium bromide 1.6 g

filled up with waaser to 1 m

"Development is preferably carried out with a resting, ie unmoving, developmental body.

The image obtained according to the method of the invention is a so-called refracted image, which is derived from a polyvision! of on the dye came with "hard" designated black dots whose feösse and frequency of image District au Bildfeesirk versohiedea and äarsa distribution practically statistically vulnerable is "teeeteiats la their statistically prone fartoilimg untersoheiclaa look dia bt on arfinduagsgemäss erhalttne image-building points of dtn in übliohen"

i 3 4 4/1 2 9 2

known halftone images present points. That according to the procedure The image obtained according to the invention is formed from the collection of points of the specified type, but these are the points constituting the image do not exist in the form of a predetermined pattern.

The images obtained by the method of the invention can of course be viewed directly, but it has to be proved advantageous, in turn, as originals for exposure to use other photographic recording materials. Typical further photographic ones suitable for this purpose Recording materials are, for example, recording materials intended for the production of lithographic plates, recording materials of the diazo type, or conventionally known silver halide-containing ones Recording materials. With each of the specified recording materials, surprisingly Obtain a sharp image in which fine details of the original, borrowed original image are remarkably clearly visible. With By means of conventionally known silver halide-containing photographic Recording materials can be used to produce images on which the fine structure of the original original image used for exposure can be recognized in a particularly advantageous manner.

If a photographic recording material for lithographic purposes is used to carry out the process of the invention, the following procedure is expediently carried out: First, the photographic recording material for lithographic purposes, which may be, for example, a recording material with an oilatin-silver halide emulsion layer, has its halide component ztjimindestens 50 Mo1 $ consists of Ohlorid and the contrast preferably has a value of Vy ^ i "V ^ 8, has, as, for example, in the US patents 3,128,180 and 3,294,537 describes directly exposed to light _t obtained by a coarse-grained image of the specified type passes through, e.g. through a coarse-grained one

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photographic image made with the help of a coarse-grained highly sensitive silver halide-containing photographic recording material j a, Bc with the aid of an X-ray film or a Film with a through-

Average particle size of more than about 0.8 / u, above

preferably of more than about 0.9 / u, was generated (referenced be on the book by Mees and James, The Theory of the Photographic Process, The Macmillan Co., New York, 1966, Table 2.1 on page 39) ο

"The resulting imagewise exposed photographic recording material for lithographic purposes is then expediently in a developer for lithographic purposes, e.g. in a Developer of the article "Formaldehyde-Hydroquinone Developers and Infectious Development ", J.A.C, YuIe, Journal, Franklin Institute, March 1945 $ No. 3 * Volume 239 Type.

By that obtained, from in a statistically random distribution The existing dots then become another photographic material directly according to the usual known ones Exposure methods, e.g. with the help of reflex exposure or projection exposure, exposed. The received imagewise exposed further photographic recording material then becomes a sharp one consisting of statistically randomly distributed points in the usual known manner Image developed «

According to a particularly advantageous embodiment of the method of the invention, a high-contrast recording material is also used as a further photographic recording material, for example a recording material of the diazo type, with the aid of which s, 3. cartographic type areas can be produced, as well as recording materials determined on the basis of lithographic plates, such as "those which have light-sensitive layers applied to metal substrates", as is the case in particular in the US patent ν- λ -, λ v> i _:. 0 09844/1 292,

- 9 3 342 601 is described.

The typical suitable photographic recording materials indicated, for example for the production of lithographic Plates for certain recording materials are useful manufactured and used in the usual known manner, with the only exception that their-exposure is not using is done by standard line grids, but that they are directly given by a grainy image of the specified type light passing through it. If recording materials intended for the production of lithographic plates are exposed according to the invention in the manner indicated, so it often proves to be advantageous to use shorter exposure times than usual.

With "direct exposure" and similar idioms is meant to be expressed that the exposure takes place without the use of conventional, known line grids.

The following examples are intended to explain the invention in more detail. The coarse-grained original images used to carry out the methods described in the examples were produced in accordance with one of the procedures designated below with A, B or 0.

Λ) X-ray film intended for medical purposes, both with a tint "transparent layer support and two delatin silver halide emulsion emulsion substrates applied to each of the two surfaces of the layer support" with slightly less (Jelatine content due to a negative ·· UXd »it continuously running image tone Hindu stepping, from a distance of I ₁ Ss members of the group. $ Wa-fct-Laape etaaaaaaaaaaen contact- ^: b "Lichtunfeverfahren expniert, whereby with the help of a Druokfoli · a smooth contact" asoh · η dem X-ray film

LOCAL INSPECTED

about 5.5 G 0.5 S. 1.9 G 1.5 G 4.6 G 4.0 G 1 liter

- 10 -

and the negative was effected. The imagewise exposed X-ray film was then developed for 15 seconds 1 minute at 20 ⁰ O by conventional methods known by a Entwioklers the following composition;

Sodium carbonate, monohydrate
Sodium sulfite
Potassium bromide
Hydroquinone

p-methylaminophenol sulfate
"Sodium Tetraphosphate

topped up with water

whereupon using the PiIm in the usual known manner was developed from sodium thio sulfate.

The positive image obtained had an easily perceptible © Graininess on ,,

B) The procedure described under A) was repeated with the Exception that © was used in X-ray film, which is only based on a coarse-grain gelatine-silver halide emulsion sofa on one surface of the support exhibited. Similar results were obtained.

CJ) The procedure described under A) »was repeated» with with the exception of this, Hontgen.fiIms is a common one well-known high sensitivity Hegativfllia was used * - " The positive image obtained also left a grainy « recognize ability «which, however, was lower than that of de® according to the procedure 1) obtained image «

At SJaJeI ₁ , 1 -

Eb was determined using a conventionally known electrophotographiaohoii Staadard-KopiQrvorriohtung a photoconductive Recording material directly to the duroh a coarse-grained photographic

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graphic image obtained by the specified procedure A). was exposed to light penetrating through, whereupon the exposed recording material was developed into a visible image in a conventional manner. It turned on Points of different sizes present in different numbers and statistically random distribution Image received that showed much more details as copies of images that are made in a corresponding manner by direct exposure of the specified photoconductive recording material using a fine-grained positive original photographic image that is generally considered to be of high quality were obtained.

Example 2

It became a dedicated one for making lithographic plates Recording material of the US patent 3 34-2 601 directly to the type described by a coarse-grained, passing through the photographic image obtained according to procedure A) Exposed to light. The exposed recording material was developed in a conventionally known manner and formed into a The printing plate was processed, and the obtained printing plate was used in a printing press for printing copies. It copies were obtained from points in a statistically random distribution that contained significantly more details Recognized as corresponding copies made using lithographic drawing material of the same Type obtained when exposure using a fine-grained, usually regarded as high quality positive photographic image was made instead of the specified coarse-grained original image.

Example 3

A recording material was used for lithographic purposes, which had a high-contrast, namely a V-value of over 4, with a Q-elatine silver halide emulsion, the halide component of which consisted of at least 50% carbon dioxide.

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According to a contact exposure method with the aid of a vacuum frame, it was exposed for 3 seconds to the light of a 6 watt lamp placed at a distance of 1.8 m using the coarse-grained photographic image obtained in accordance with procedure A). The image-wise exposed recording material was then determined to develop fine lines using a. Developer initially for about 30 seconds while stirring the developing bath and then for about 2 1/2 minutes in a stationary, unmoving development bath, developed in the usual known manner. The developer solution used, which contained hydroquinone, sodium formaldehyde bisulfite, sodium carbonate, sodium tetraphosphate and boric acid, as described, for example, in U, ^c jA-Pa.t ent writing 2 843 483, was advantageously stirred until the image was even under darkroom light became visible, whereupon the stirring was stopped and the further development was carried out with the developer bath at rest. The obtained printing plate suitable for lithographic purposes had a negative image "consisting of hard dots present in a randomly distributed distribution.

Example 4

The procedure described in Example 3 was repeated with the exception that the exposure was carried out using an after Method B) of the coarse-grained original image obtained was carried out. Accordingly, favorable results have been obtained. ■

Example 5

The procedure described in Example 3 was repeated with the exception that development was carried out using an after Procedure G) the coarse-grained original image obtained was carried out. Accordingly, favorable results have been obtained.

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Example 6

Using the negative obtained according to Example 3, from a negative image consisting of a statistically random distribution of points, a positive image was produced, by using a recording material intended for lithographic purposes as in Example 3 according to a contact exposure method exposed and developed according to the method described in Example 3. That obtained in this way, from statistical randomly distributed hard dots existing positive image was then used as the original image for exposure of an under known as "Bruning Resolute diazo paper" paper-based direct positive recording material of the diazo type used. The exposed diazo type recording material was then developed in a conventional manner. It became a sharp image that could recognize extremely fine details left, received. ■

Example 7

JiJs was made according to that described in U.S. Patent 3,342,601 The photosensitive lithographic recording material produced by a method according to Example 3 negative image obtained exposed to light passing through. The exposed recording material was developed, whereupon the obtained lithographic plate was used on a printing press for printing copies by conventionally known methods. It made high quality copies that were remarkable Hesse recognizes fine details of the original picture used, preserved.

Example 8

The procedure described in Example 7 was repeated except that development was carried out using the negative image obtained by the procedure described in Example 4. Accordingly, favorable results have been obtained.

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Example 9

The procedure described in Example 7 was repeated,
with the exception that development using "Using the
the negative image obtained by the procedure described in Example 5 was carried out. Accordingly, favorable results have been obtained.

Example 10

A light-sensitive, fine-grain, silver halide-containing portrait paper was exposed to the light passing through a negative image obtained in Example 3.
The image-wise exposed portrait paper was then developed with the aid of a conventionally known standard fine grain developer, whereupon it was fixed in the conventionally known manner using sodium thiosulphate. It turned on
in a statistically random distribution existing image obtained, which is characterized by great sharpness and clear reproduction of the surface structure of the used
Original image.

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Claims (6)

P_a_t_e_n_t_a_n_s_E_r_ü_c_h_e Photographic process for producing images that are made in varying numbers as well as statistically random Distribution of existing points of different sizes consist of exposure and development of a photographic recording material, characterized in that that a high-contrast photographic recording material with a y-value τοη at least about 4 through a coarse-grained original image with a grain size of at least about 20 exposed and the image-wise exposed recording material developed. 2. The method according to claim 1, characterized in that the coarse-grained original image by exposure of a photographic Recording material consisting of a Layer carrier and at least one coarse-grained layer applied to at least one of the surfaces of the layer carrier Gelatin-silver halide emulsion layer using a continuously running original Image tone, as well as by customary known development of the exposed Produces recording material. 3. Process according to Claims 1 and 2, characterized in that the high-contrast photographic recording material is used one comprising a support and a gelatin-silver halide emulsion layer applied thereon for used for lithographic purposes existing recording material. - 4. The method according to claim 3, characterized in that one received, from in different numbers as well as * statistically random distribution of existing points of different sizes existing image for exposure 00 984 4/129 2 another photographic recording material used and the image-wise exposed further recording material obtained in this way for a further, from points that are present in different numbers and statistically randomly distributed developed over the existing image, 5 «Method according to claim 4, characterized in that as a further photographic recording material is a recording material diazo specific for the production of lithographic plates recording material, w a silver halide photographic recording material or a particular for performing electrophotographic processes photoconductive recording material used" 6. Process according to Claims 1 to 5 *, characterized in that that as a high-contrast photographic recording material a silver halide recording material with a y value of at least about 8 and as Developer uses a developer for lithographic purposes. 0 0 9 8 U:. ■ ' 1 2 9 2