DE1572306A1 - Lithographic printing process and photographic material suitable therefor - Google Patents

Description

Registration number. 120 308

Eastman Kodak Company, 343 State Street, Rochester, New York State, United States of America

Lithographic printing process and photographic material suitable therefor

In the known lithographic printing processes Printing plates used, which accept printing ink differently when moistened with water. The plates have surfaces that accept oleophilic, fat printing inks and hydrophilic, printing ink-repellent surfaces.

Numerous methods are known by which lithographic printing plates can be made. One, quite common Process is based on the fact that on a hydrophilic surface by photographic means through different Hardening of an organic, photosensitive colloid layer an oleophilic image is generated. In other known methods of making lithographic printing plates an already preformed pattern can be transferred from one carrier to another to make a corresponding to get different printing ink accepting printing plate.

VaD 0FHG1NAJ-

• 00882/0990

Also, an oleophilic pattern can have a hydrophobic surface photographic or otherwise formed and the pattern used as a resist to remove the uncovered to convert hydrophobic surfaces into hydrophilic surfaces, for example by hydrolysis in cellulose ester printing plates happens.

A particularly simple photographic method of manufacture of lithographic printing plates is described in U.S. Patent 3,146,104. The procedure is based on the formation of a developable silver halide image by imagewise exposure of a hydrophilic, organic Colloidal silver halide layer, such as in particular a gelatin silver halide emulsion layer, and then developing the exposed silver halide no further operations, such as B. Etching or washing off the unhardened areas, required to make the printing plate to obtain. Moreover, this method can be carried out in such a way that, starting from either positive or negative originals, positive plates are produced.

The method disclosed in U.S. Patent 3,146,104 uses silver halide emulsion layers that are in the emulsion itself or in a layer in effective contact therewith, a developing agent for silver halide contains, which in the presence of the hydrophilic, organic colloid, which forms part of the emulsion when it is oxidized in the development reaction, an oleophilic,

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That is, an image that accepts printing ink is produced, the development of the exposed silver nodule being effected by treating the emulsion layer with an alkaline solution. Optionally, this alkaline solution can also contain the developer compound, if this is not already present in the photographic material. The plate is then moistened for printing, whereupon the desired lithographic reproduction, which will be negative with respect to the original, can be made on a suitable printing press. If, however, positive prints are to be made with reference to the original, the photographic material described above can additionally contain a fogged silver halide emulsion layer as the top layer. If such a photographic material is exposed under an original image and the developing agent which is in effective contact with the silver halide is activated, it reacts with the silver halide of the lower emulsion layer to form a negative image, while the unused developing agent in the unexposed areas of the lower emulsion layer upwards this layer migrates into the veiled and silver there with their oxidation with the hydrophilic organic colloid is an oleophilic and "it regards positive to the original image. A positive prints supplying printing plate is obtained even when using a direct-positive silver halide emulsion, such as is described, for example in the US Patents 2,541,472 and 2,497,875. You can also get a, positive

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BATH Often

Lithographic printing plate providing prints is also obtained in such a way that the exposed photographic material only in a non-tanning developer compound, such as. B. hydroquinone, as well as sulfite-containing developers developed whereupon the undeveloped silver halide is flashed with white light and then in a developer compound containing alkaline solution is developed, the developer compound being oxidized during development in the presence of the hydrophilic organic colloid in the silver halide emulsion layer forms an ink accepting image.

US Pat. No. 3,146,104 describes other methods for producing the silver halide image, which is developed into an oleophilic image, e.g., a silver halide complex image can be obtained by a diffusion transfer process which can then be developed to form an oleophilic image pattern. Silver halide images produced by rehalogenation of silver images can also be produced with the developer compounds described below to be developed into oleophilic images, fcs is ultimately even possible, practically usable to manufacture lithographic printing plates in such a way that they are unused during the development of a silver halide image Developer compound is transferred to a receiving sheet, which is on a suitable carrier a hydrophilic organic colloid, d. H. Gelatin, with dispersed therein

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contains veiled silver halide and possibly also an oxidizing agent such as manganese (IV) oxide, If the unused developer is then also transferred a receiving sheet of the type described, it will be in the presence the hydrophilic organic colloid is oxidized, d. H. a printing plate is obtained. When changing this general Process for making lithographic printing plates is the unconsumed developer compound, the originates from the first development of a silver halide image, transferred to a receiving sheet, which in this case on eiern carrier only has a hydrophilic, organic'colloid layer, whereupon this layer with a solution of a Gedgneten oxidizing agent, such as. B. iron (III) chloride or iron (III) sulfate-ethylenediaminetetraacetic acid tamponized to the developer compound present in the receiver sheet to oxidize, whereby reaction with the colloid of the hydrophilic, organic colloid layer obviously occurs, d, h. oleophilic areas corresponding to the image are obtained on the colloid layer.

It has now surprisingly been found that the sensitivity of a photographic material useful for making lithographic printing plates can be increased without adversely affecting other sensitometric properties, such as, for example, the contrast or the utility of the photographic material is thereby somehow restricted when in the silver halide emulsion layer of the photographic material, e.g.

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from that described in U.S. Patent 3,146,104 Type, as an optical or spectral sensitizer, a oxacarbocyanine or benzimidazole carbocyanine dye is used.

Accordingly, the invention relates to a process for the production of printing plates by photographic means, in which a photographic material, consisting of a support and a non-fogged sensitized gelatin silver halide emulsion layer applied thereon, and optionally an intermediate layer between the carrier and the emulsion layer and another over the non-fogged one Layer applied, veiled gelatin-silver halide emulsion layer, the outer emulsion layer of which has a hardness such as a gelatin layer hardened with about 4.4 to 33 ρ formaldehyde (100%) per kg gelatin, image- edited exposed and developed in the presence of a polyoxybenzene developer compound with an alkaline solution, which is characterized in that a material is used whose non-fogging silver halide emulsion layer is sensitized with at least one oxacarbocyanine and / or benzimidazole carbocyanine dye.

Surprisingly, it has been shown that the sensitivity of a photographic material according to the invention i is greater by at least 25 than that of a comparable for Her "well-known tellung lithographic Druclplatten

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th photographic material whose emulsion layer contains a cyanine, styryl or merocyanine dye.

am suitable for carrying out the method of the invention photographic material accordingly contains z. B. on a support a) a gelatin layer which has a developer composition consisting of a polyoxybenzene compound, and b) over the gelatin layer an unveiled gelatin-silver halide emulsion layer, the gelatin of which is hardened with a hardening agent such that its hardness is that of about 4.4 corresponds to up to 33 g formaldehyde (100 l) per kg gelatin hardened gelatin layer, and in the silver halide emulsion layer at least one oxacarbocyanine dye of the general formula

'CH-C-CH-C

R.

NJ

0 '' X

and / or a benzimidazole carbocyanine dye of the general formula

II.

* Ii

_R.
^K

¹ ·

Ri

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BATH

where mean:

π and Q ¹ each represent the atoms or groups of atoms required to complete a PhenyT nucleus;

R ₁ and R- each represent an alkyl group;

R_ is a hydrogen atom, a lower alkyl or

Aryl group;

Y is sulfur, oxygen, nitrogen or

Selenium atom,

Z is a = QT or ^S NR ₆ radical, in which R ₄ , R ₅

5
or R ₆ each from a lower alkyl group

exist;
A is an alkyl group and

X "an anion, as optical or spectral

Sensitizers.

The anion Χ "in the formulas can, for example, from a chlorine, Bromine, sulphite or toluene sulphonate ion, including internal ones Salts exist.

The phenyl nuclei completed by the atoms or atomic groups O and Q ¹ can be unsubstituted or by z. B. lialogenatoms, such as chlorine or bromine; Alkoxy groups, such as. B. methoxy, ethoxy, propoxy, isopropoxy or butoxy groups, alkyl groups, such as. B. methyl, ethyl, propyl, isopropyl

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or butyl groups, hydroxyl groups, amino groups, alkylamino groups, like ζ. B, methylamino, ethylamino, propylamino, or butylamino groups, dialkylamino groups, such as. B. dimethylamino, Diethylamino, dipropylamino, dibutylamino, methylethylamino, methylbutylamino, or ethylbutylamino groups, Aryl groups, such as ζ. B. Pheny-1-, chlorophenyl, bromophenyl, Methylphenyl, ethylphenyl, methoxyphenyl, ethoxyphenyl, α-naphth / l-, ß-naphthyl-, 2-oxynaphthyl-, 2-methoxynaphthyl-, or 2-ethoxynaphthyl groups, carbomethoxy groups or carbethoxy groups may be substituted. That is, these phenyl nuclei may optionally contain more than one substituent, either the same or different, if so they are substituted.

The substituents R ₁ and Fi ₂ in the formulas can consist of the same or different alkyl groups, such as, for example, either alkyl groups themselves, or of carboxyalkyl, sulfoalkyl or sulfoalkoxyalkyl groups, etc. Preferably, R and R ~ consist of lower alkyl groups such as B. methyl, ethyl, propyl or butyl groups, although possibly also higher, d. h, those alkyl groups which contain more than 4 carbon atoms, such as, for example, a pentyl or hexyl group, come into consideration. If R ₁ and R ₂ consist of carboxyalkyl groups, sulfoalkyl groups or sulfoalkoxyalkyl groups, the individual substituents can, for. B. carboxymethyl, ß-carboxyethyl, δ-carboxypropyl or -o-carboxybutyl groups, etc., ß-sulfopropyl, 6-sulfopropyl or

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δ-sulfobutyl groups etc., or ß-sulfomethoxyethyl, P- (P-sulfoethoxy) ethyl ~, ß- (δ-sulfopropoxy) ethyl, or δ- (β-sulfoethoxy) butyl groups be.

If R, consists of a lower alkyl group, this can z. B. be a methyl, ethyl, propyl, isopropyl, butyl or isobutyl group, while, if R, from an aryl group exists, this z. ß. a phenyl, ethylphenyl, methoxyphenyl, ethoxyphenyl, a-naphthyl, ß-naphthyl, 2-oxynaphthyl, 2-methoxynaphthyl or 2-ethoxynaphthyl group be.

The substituents R., R _r and R. in the radical Z of the formula II preferably each consist of a lower alkyl group, such as. B. a methyl, ethyl, propyl, isopropyl, butyl or isobutyl group, etc.

The substituent A in formula II can, for. B. from a methyl, ethyl, propyl or butyl group or another lower alkyl group or from a substituted alkyl group, such as. B. a carboxyalkyl group, d. h, one Carboxymethyl, β-carboxyethyl, α-carboxypropyl or 6-carboxybutyl group or consist of a dialkylamino group, such as a dimethyl or diethylaminoethyl group,

Characteristic oxacarbocyahine dyes which can be used according to the invention are compiled in Table I.

909882/0990. W) or: g; n /, ·

In this table, ^{the various, optionally present substituents of the two phenyl nuclei of dyes of the general formula I are indicated under M} Q "and" Q ¹ ", whereby it should be noted that more than one substituent is also associated with each of the nuclei Q and Q ¹ can be, that is, for example, two chlorine atoms per nucleus in the dye listed under item (5), while the various alkyl groups present in the individual dyes are listed under "R" and "R"

16 ⁵

from a hydrogen and Y from an oxygen atom.

Table I.

1 Phenyl Phenyl Sulfobutyl Sulfobutyl 2 Phenyl Phenyl ß-sulfomethoxy
ethyl β-sulfomethoxy
ethyl 3 chlorine chlorine Sulfobutyl Sulfobutyl Phenyl Phenyl Sulfopropyl Sulfopropyl 5 Dichloro Dichloro Sulfopropyl Sulfopropyl 6th Methoxy Methoxy Sulfopropyl Sulfopropyl 7th bromine bromine Sulfopropyl Sulfopropyl 8th Phenyl Chlorine- Sulfobutyl Sulfobutyl 9 Phenyl Met ho xy- Sulfobutyl Sulfobutyl 10 Ghlor chlorine ethyl ethyl 11 chlorine bromine Sulfobutyl Sulfobutyl 12th Oxy chlorine Sulfobutyl Sulfobutyl 13th Phenyl Phenyl ethyl ethyl IH bromine bromine methyl methyl 15th Ethoxy Ethoxy ethyl ethyl 16 unsubstituted
performed unsubstltu-
iert methyl methyl

or :;

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17th bromine Phenyl 18th chlorine chlorine 19th Pibroma Dibroma 20th chlorine Phenyl

Sulfobutyl sulfobutyl

Sulfobutyl ethyl

ß-carboxyethyl ethyl

Sulfopropyl ethyl

Characteristic benzimidazole carbocyanine dyes which can be used according to the invention consist e.g. of the connections listed in the following table.

Dichloro Table II Q ' ü v Z 2 ^H 5 A. X Dibroma Dichloro Sulfobutyl Sulfo
butyl N-C 2 ^H 5 ethyl 1 unsubstituted
performed Dibroma Sulfobutyl ethyl N-C 2 ^H 5 Ätüyl. 2 unsubstituted
performed unsubstituted
performed Sulfobutyl Sulfo
butyl N-C CH-
OH ₃ ethyl 3 unsubstl »
performed Dichloro methyl ethyl C. OH ₃
CH- Carboxy
methyl 4th Dichloro methyl ethyl C. Diethy1-
aminoeth * 5

The substituent R ~ in the dyes in Table II consists Each from one hydrogen atom.

Except for oxacarboeyoiin stains, whose olied Y, as in the case of the in the compounds listed in Table I from an oxygen atom Is it also best to apply these to the general form i.sl I fa.ll ^ :: as dyes proved to be excellent, the other- ? & <s "LIe of a Sauf.-stoffatonjs a S efc · ν Γ el ^ GOm, a Stl - ^ - kstoff-

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BAD ORJGLMAL

atom or a selenium atom. Are excellently suited also dyes, whose substituent R-, not, as in the examples of Table I is composed of hydrogen, but of a lower alkyl group or an aryl group.

According to one embodiment of the method of the invention a silver halide emulsion layer containing an oxacarbocyanine dye containing photographic material exposed imagewise in the presence of the developing agent, whereupon the material treated with an alkaline solution - and the so obtained lithographic plate is inked. The developer connection can thereby in the alkaline activator solution or housed in the photographic material. Is the emulsion of the photographic material used from the developable Type, you get a negative plate with respect to the original, while when using direct-positive Emulsions positive printing plates are obtained.

According to another embodiment of the method of the invention, where positive-working plates are used, the photographic material * consists of a material containing an oxycarbocyanine or benzimidazole carbocyanine dye sensitized silver halide emulsion layer on a support Is applied, in addition, directly in the emulsion layer or immediately adjacent to this layer, a developer compound housed of the type described and with a veiled silver halide layer over the emulsion layer

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emulsion layer is arranged. The material activated and developed after exposure to an alkaline solution contains a negative image of the original in the exposed areas of the lower emulsion layer, the unused developer compound diffusing from the unpainted areas of the negative emulsion layer into the veiled emulsion layer and a positive one there "ie" has formed the image in the areas of the negative emulsion layer nlchtbelichteten entspi ^l ^ Ciisnöen surfaces of the obfuscated layer is a positive image olöophiiee arisen accepts the printing ink and clamped on a printing press lithegraphisehe provides positive prints the original image. In "this embodiment of the method, moreover, if a negative-working plate is to be produced, photographic materials containing a direct-positive emulsion can also be used. ***"

Other specific embodiments of the lithographic printing process of the invention are described below.

In the described embodiments of the method surfaces of the printing plate that accept the printing ink on a background consisting of a hydrophilic polymer alkaline activation of a developer compound in the presence of a hydrophilic, organic colloid silver halide emulsion layer obtain. This creates a SilberbiM in the development areas, which are at the same time those in the development contain formed oxidized en ^ winding compound.

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Particularly suitable developer compounds are polyoxybenzenes, by one or more halogen atoms, phenyl groups or at least containing two and preferably 2 to 6 carbon atoms Alkyl groups are substituted, in particular 1,2-dioxybenzo-Ie. Examples include o-chloro- or o-bromohydroquinone; 4-phenylbenzatechol; 4-tert. Butyltoenzatechol; Pyrogallol; 4-n-butylpyrogallol; Nordihydroguaiaretic acid; i », 5-dibromopyrocatechol; SiSjö-Tribrom-Jl-phenylbrenskatechin or l-phenyl-3- (N-n-bexylcarboxamidoJ - ^ - jjpCß-hydrochinolyläthy ^ phenylazoJ 5-pyrazolone. Esters of such compounds, such as formates and acetates of pyrogallol, which are in alkaline solution can also be used hydro glaze; be used.

If necessary, it can be expedient, except for one of the described ones Polyoxybenzenes, such as pyrogallol, another HilÄ developing compound, such as monoraethyl-p-aminophenol or a To use 3-pyrazolidone, which, if used alone, would not produce oleophilic images, but in combination with a polyoxybenzene developing agent enhances their effect "and works synergistically.

The drawing shows two different embodiments in FIGS. 1 and 2 of photographic materials according to the invention at various stages in the manufacture of lithographic Printing plates in section.

BATH ORIGINAL

scsa η: / ο ■; ■? ■ ;.

In Pig. 1 is a negative-positive material and in FIG. 2 a Positive-positive material shown.

The material shown in Fig. -1 consists of a carrier 10, e.g. made of paper or a film support, a hydrophilic, organic colloid layer 11, e.g. of gelatin with a developing agent dispersed therein and carbon black or black, colloidal silver as antihalation agent and a gelatin silver halide emulsions layer 12, which is coated with a Oxacarbocyanine dye or a benzimidazole carbocyanine dye is sensitized.

If the phctographic material shown in Fig. La), such as indicated by 13, exposed, alkaline activated and then colored, so it achieves that shown in Fig. 1 b) Appearance, i.e. the area 14 corresponding to the exposure area 13 of the original material (according to development) the developed silver and the reaction product of the oxidized developer compound and the hydrophilic, organic colloid present in the sensitized emulsion layer was included. After being tinted with a printing ink, the material bears the color image 15. The unexposed and consequently Undeveloped areas 16 of the emulsion layer 12 repel the printing ink in the moistened state.

The material shown in Fig * 2 a) consists of a carrier 20, see illustration made of paper or a film underlay of a hydrophilic

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len colloid layer 21 with the developer compound and a of the aforementioned antihalation agents of a hydrophilic organic colloidal silver halide emulsion layer 22 containing an oxacarbocyanine or benzimidazole carbocyanine dye and a fogged silver halide emulsion layer 23

If this material is exposed at 24, it is activated alkaline and colored with printing ink, it takes on the appearance shown in Fig. 2 b). The layer developer compound 21, which was not used for the development of the negative silver image in the areas 24 of the emulsion layer 22, has produced a positive silver image in the areas 25 of the veiled emulsion layer 23. Accordingly, form when inking printing ink images 26 in the areas 25, which consist of silver and the reaction product of the in the emulsion layer containing hydrophilic, organic colloid and the oxidized developer bond exist, since these areas at the development reaction have become oleophilic, while the area indicated at 27 has remained hydrophilic and therefore printing ink repels.

The emulsion layers, especially the outermost ones EmuMons layers, i.e. in the material shown in Figure 1 the layer 12 and in the case of the Madie layer 23 shown in FIG. 2 should be largely hardened in order to

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• prevent the alkaline activated and then colored emulsion layers from sticking to, for example, printing blankets, printing paper, etc. That is to say, the emulsion layers should expediently be just as hard as, for example, a gelatin layer that contains at least about 4.4 and preferably about 4.4 to 33 g of formaldehyde (100 %) per kg of gelatin *

In a particularly advantageous embodiment of the material According to the invention, the developer compound is in a special layer under the orthochromatically sensitized, housed unveiled silver halide emulsion layer. Such a material delivers particularly sharp images at the same time particularly large exposure width.

The following Befeplele are intended to further illustrate the invention.

example 1

Two spectrally sensitized fine grain silver chloride emulsions, one of which, hereinafter referred to as ⁿ A ⁿ , contains the merocyanine dye, 3-ethyl-5 - {(3-ethyl-2- (3H) -benzoxazolylidene) isopropylidene ~] rhodanine and the other, im following 'with "B" designated emulsion, an oxacarbocyanine dye of the general formula I, namely anhydro-9-ethyl-5,5'-diphenyl-3 »3'-di (3-sulfobuty1) oxacarbocyanine hydroxide monosodium ^ Iz contained, which in the rest, however, had the same composition

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sen, were prepared as follows:

For emulsion I. the dispersions II. And III. added:

I. ^ 3.5 g of a fine-grain silver chloride emulsion containing 1 mol of AgCl ^{per 1350 cm 3.}

II. 10.0 g of a paraffin dispersion, prepared as follows: 80 g of melted paraffin were ^{dispersed in 100 cm 3 of} a 10% photographic gelatin solution * which contained 5 cm ^{3 of} a 10% alkanol B solution.

III. 10 g of a dispersion of 1-phenylpyrocatechol, prepared as follows: 50 g of 1-phenylpyrocatechol were dissolved in 100 cm ^{3 of dibutyl phthalate at 60 to 70 °} C., whereupon the solution was dissolved in 500 cm ^{3 of} 10% photographic gelatin solution, which was previously 50 cm ³ 7.5 Jt saponin solution had been added, was dispersed. The mixture was then passed through a colloid mill 5 times. Finally, 1.0 g of a 15% strength saponin solution, 1.0 g of a 10% strength formaldehyde solution and 20 ml of water were added to the mixture.

The emulsions were applied to a filetrip in such a way that 6.5 g of emulsion accounted for about 0.09 square meters of support surface.

The dried films were exposed under a halftone image and then for 20 seconds in a 1% sodium carbonate, mono hydrate solution activated, whereupon the developed in this way Films on a lithographic press in the known manner ©

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colored with printing ink. The areas of the lithographic plates which took on the color corresponded to the exposed areas Ik of the material shown in FIG. 1, ie the prints obtained (a total of about 50 prints were made) were positive with regard to the negative used. The sensitometric properties of the films prepared with the two different dyes sensitized emulsions A and B are shown in Table M.

Table III contrast Development
speedy-.
kelt Film, made
with: Relative
Sensation
opportunity similar similar Emulsion A
Emusion B 100
280

Instead of accommodating the developer compound in photographic material as described, the developer compound can also be used in the activator solution. Furthermore, in order to further improve the different absorption capacity for the printing ink between the oleophilic and the hydrophilic surfaces, the printing surface can additionally contain substances such as zinc oxide, aluminum oxide, carboxyalkyloxyethyl cellulose or polyacrylamide. In addition, after development with the alkaline activator solution, the plate surface can also be freed of alkali residues with a customary lithographic desensitization and etching liquid, such as a solution containing 0.15 % phosphoric acid or the like. "

809882/0990

Example 2

Three photographic materials one essentially as in FIG The assemblies shown in Figure 2a were fabricated according to the following general procedure:

A paper support was at 40 ° C. with a developer dispersion A coated in such a way that 11.7 g the dispersion was omitted.

This developer dispersion was prepared as follows: 5 g of 4-Phenylbrenzkatechin were dissolved in 50 g of dibutyl phthalate at room temperature and the solution at a temperature of 40 ⁰ C in a 290 g 10 £ strength gelatin solution, 25 ml of 7 »5% - sodium saponin and the solution containing 180 ml of water was dispersed. The dispersion was then passed three times through a well-cooled colloid mill and 400 g of the dispersion were then mixed with 400 g of a 3 gelatin solution containing 12.5 g of neutral colloidal silver per 454 g of solution; Mix 20 ml of IS i saponin solution, 2.5 ml of 2% formaldehyde solution and 27 »5 nil of water.

over the layer containing the developer dispersion A. a silver chloride iodide emulsion containing per mole of silver halide Contained 100 g gelatin and of the 2480 g (before. Application) with

300 ml of ethyl alcoholic dye solution,

9882/0990 ^ ^{0 ml 10} * ^"gelatin solution,

90 ml 7 Jf Triton X 200 solution,

68 ml of 10 formaldehyde solution and 222 ml of water

were mixed (total weight of the emulsion containing the additives = 4000 g) applied so that on about 0.09 square meters Support surface 5 »35 ml of this emulsion were omitted.

As dyes in the alcoholic dye solution were obtained on each 1 mol of silver halide, used: in an emulsion C: 150 mg of the merocyanine dye, 3-ethyl-5-Q3 »ethyl-2- (3H) -benzbxazolylidene) isopropylidene] rhodanine;

600 mg of anhydro-5 _J 5 ^l dichloro-9-ethyl-3,3 di ^t (3-sulfopropyl) oxacarbocyaninhydroxyd, sodium salt, and: in an emulsion D

in an emulsion E: in addition to the 600 mg of the last-mentioned oxacarbocyanine dye, a further 100 mg of anhydro-5,5 ¹ -6,6 »-tetrachloro-1,1'-diethyl-3,3 * -di (3-sulfobuty1) benzimidazolocarbocyanine hydroxide.

Finally, this silver chloride iodine emulsion was passed on another silver chloride emulsion layer (which corresponded to layer 23 of Fig. 2) applied in such a way that on about 0.09 square meters Support area 7.0 ml of the emulsion composed as follows omitted:

Gelatin silver chloride emulsion with 1 mol of silver chloride per 3600 g 360 g

Water 200 ml

0.25 N sodium hydroxide solution 2 ¹ »ml

2.5t aqueous formaldehyde solution 4.6 ml

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BATH ORIGINAL

3.5 ml 10.0 ml 2.0 ml 95.9 ml

- 23 -

The mixture was heated with stirring to ¹ IO ⁰ C and held for 40 minutes at this temperature while it was chemically fogged at the same time. (Also Litfht or other known fogging agent may optionally be used for obfuscating). Then the fogged emulsion, before it was applied over the unveiled emulsion layer, was still with

Sulfuric acid, 2.0 normal,

15 i-strength aqueous saponin solution

2 ϊ aqueous formaldehyde solution

water
diluted.

Sections of the photographic materials produced were exposed under a halftone positive image, then developed for 60 seconds in a ¹ I Z strength sodium carbonate, monohydrate solution, immersed in an aqueous 2 % acetic acid stop bath for 1 minute, freed from excess liquid by squeezing off "and finally on treated with 0.1% phosphoric acid in a lithographic press and colored.

The "plates" colored with the printing ink had an appearance as shown in FIG. 2b. Ie, was in the development of exposed photographic materials in the development of negation ^ emulsion layer un? Ert>ratch'i ^ bli-I'c ^ ns

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Developer into the veiled on the surface Silver chloride emulsion layer diffused and had an oleophilic silver image in it in the original unexposed Areas corresponding to areas are generated.

The sensitometric properties determined for the three differently sensitized emulsions are given in Table IT compiled:

Table IV

Relative Contrast Development Sensitivity Speed

Emulsion C 100

Emulsion D 398 bigger gvöfte? more quickly

Emulsion E 4 ^ 7 bigger bigger & er faster i.e. better

From the data given in the table it can be seen that with Oxacarboeyanine dyes alone or combined with a BerKiMldaEolcarbocyanine dye, sensitized photographic Materials have a greater sensitivity than those corresponding to materials that are sensitive to merocyanine dyes are.

bec-ihrlebeneii procedures were photo dii with £} SiS-DiiiV.hyl - ^ - meth

BATH ORIGINAL

thiazolocarbocyanin iodide and b) 3,3 *, 9-trlethyl-5,5 * -diphenyloxacarbocyanin iodide sensitized, manufactured and tested. These materials had one versus a comparative material 27 K) or 400 JIf greater relative sensitivity. This means that oxathiacarbocyanine dyes give a slight increase in sensitivity, but that oxacarbocyanine dyes do are far superior to the oxathiacarbocyanine dyes.

Example"*"

Other photographic materials were prepared according to the procedure described in Example 1, those with various Dye-sensitized emulsions, each containing 500 mg of dye per mole of silver halide, in this way via the A layer containing ^ -phenyl catechol developer was applied to a support surface of about 0.09 square meters 145 mg of silver were used.

Some of the dyes used in this example were styryl, cyanine and merocyanine dyes (dyes No. I up to and including XVIII of the following compilation), their use in for the production of lithographic Plates of certain photographic material is known, on the other hand to oxacarbocyanine and benzimidazole » Bocyanine dyes (dyes Nos XIX up to and including XXXIV the compilation) as used according to the invention.

BATH

909882/0990

Styryl dyes dye I:

Cl

CH ₃ CH ₅ N (C ₀ H _5. ) J ά ά. do

^ C-CH = CH

2 "5 N (CH ₃ )

Cyanine dyes dye II:

Thiacarbocyanin dyes dye III:

C = CH-C = CH-C

PW

^CH 3

HC-CH ₃ HC-CH ₃

OSO

Merocyanine dyes of the general formula;

O = O C = CH-C = C ^

90 ^ 882/0990 BATH

Dye IV: (a) H, (b) -CH ₂ -COOH Dye V: (a), H, (b) -CH-CH ₂ -COOH

COOH

Dye VI: (a) CH ₃ , (b) C ₃ H merocyanine dyes of the general formula:

0 o = C rN- (b)

C = CH-CH = C C = S

(i)

Dye VII: (b) C ₂ H ₅ , (c) -C ^ -N-CC ₃ H ₅ J ₂ , (g) H

Dye VIII: (b) C ₃ H ₅ , (c) -N 0, (g) H

Dye IX: (b) CgH ₅ , (c) -CH ₂ -COOH, (g) CgH

Merocyanine dyes of the general formula:

CH _? - S. C N- (g) C = CH-C = C / CH, - IT (b) ^X S - C = S (a)

Dye X: (a) CH ₃ , (b) CH ₃ , (g) -CH ₂ COOH Dye XI: (a) CH ₃ , (b) H, (g) -CH ₂ COOH

Dye XII: '(a) CH ₃ , (b) C ₀ K ₅ , (g) -CH ₂ COOH Dye XITI: (a) C ₂ H ₄ COOH, (b) CH ₃ , (g) -C

Merocyanine dyes of the general formula:

CH ₂ - S Jc - N- (g)

I C = CH-CH = C I

BAD QRIStsl

Dye XIV: (a) CH ₃ , (b) C ₃ H ₅ , (g) Dye XV: (a) CH ₃ , (b) C ₃ H ₅ , (g) -

Dye XVI: (a) CH ₃ , (b) C ₃ H ₅ , (g) -C ₃ H ₁₁ -N Jp

Dye XVII: (a) CH ₃ , (b) -CgH ₅ , (g) -C ₃ H ₁₁ -N (C ₃ H ₅ J ₂ Dye XVIII: (a) C ₁₁ HgSO ₃ K, (b) C ₃ H ₅ , (g) -CgH ₅

Oxathlacarbocyanin dyes Dye XIX

C = CH-CH = CH-C

Oxacarbocyanine dyes of the general formula:

C = CH-C = CH-C

CH ₀ 1 ^c CH ₂

CH- (R) SO ₃ Na

Dye XX: (g) Cl ", U ₁ ) Cl", (R) H *

Dye XXI: (g) CH ₃ O ", U ₁ ) CH ₃ O", (Rj. H *

Dye XXII: (g) CgH ₅ ", U ₁ ) C ₅ H ₅ ", (R) CH ₃

Dye XXIII: (g) CgH ₅ ", U ₁ ) Cl", (R) CH ₃

Dye XXIV: (g) CgH ₅ ", U ₁ ) CH ₃ O", (R) CH ₃

Dye XXV: (g) CgH ₅ ", U ₁ ) CgH ₅ ", (R) CH ₃ C

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CH ₃ dye XXVI: (g) CgH ~ (g _a ) CgH ₅ ", (R) CH ₂ -CH ₂ CH-SO ₃ ⁰

Dye XXVII: (g) C ₅ H ₅ ",

C ₆ H ₅ ", (R) -

, COO *

Oxabehzimidazolocarbocyanin dyes of the general formula:

(R ₂ ) (Ro)

ι ⁴¹ s 3

C = CH-CH = CH-C

Dye XXVIII: (g) H, (g ₁ ) Cl ₃ , (R) CH ₂ CH ₂ CH ₂ SO ₃ Na,

CH ₃
(R ₁ ) CH ₂ CH ₂ CHSO ₃ *, (H ₂ ) C ₂ H ₅ , (R ₃ ) C ₂ H ₅

Dye XXIX: (g) H, (gi) Cl ₂ , (R) CH ₂ CH ₂ CH ₂ CH ₂ SO Na,

CH ₃
(R ₁ ) CH ₂ CH ₂ CHSO ₃ ⁹ , (R ₂ ) C ₂ H ₅ , (R ₃ ) C ₂ H ₅

Dye XXX: (g) H, Cg ₁ ) Cl ₂ , (H) C ₂ H ₅ , (R ₁ ) C ₃ H ₅ ,

Dye XXXI:

(R ₂ ) CH ₂ CH ₂ COOH, (H ₃ ) H

(g) H, (S ₁ ) Cl ₂ , (R) C ₂ H ₅ , (R ₁ ) C ₂ H ₅ ,

(R ₂ ) C ₂ H ₁₁ -N (C ₂ Hg) ₂ , (R ₃ ) H

Benzimldazolocarbocyanine dyes dye XXXII:

C = CH-CH = CH-C

CH ₀ 1 ^c CH ₂

HC-CH.

so ₃ * ^:

Cl

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Benzimldazololndocarbocyanin dyes of the general formula: CH "CH.

Cl S Ύ ^ I—

C = CH-CH = CH-C

C ₂ H

Dye XXXIII: (a) -CH ₂ COOH
Dye XXXIV: (a) -C ₂ H ₁₄ -NCC ₃ H ₅ J ₂

Sections of these materials were recorded on an Eastman IB sensitometer exposed and developed for 1 minute in a developer (Kodak D-72 developer (1: 1)), then fixed, washed and dried.

The sensitometric results obtained with the various materials are summarized in Table V.

Table V

material Sensitivity with color enlargement ge fabric no. compared to the non- sensitized Comparative material (lop; E units) I. 0.80 II 0.50 III 0.15

Other sensitometric properties etc. with respect to the reference material

0.63

0.22 0.85

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greater veil on storage

lower contrast, bigger. Veil on storage

η
ti

BATH ORIGINAL

VII

0.75

VIII 0.68 IX 0.15 X 0.5 & XI 0.30 XII 0.60 XIII 0.45 XIV 0.65 XV 0.30 XVI 0.50 XVII 0.65 XVIII 0.43 XIX 1.03 XX 1.32 XXI 1.48 XXII 1.30 XXIII 1.55 XXIV 1.46 XXV 1.48 XXVI 1.40 XXVI 1.42 XXVIII 1.22 XXIX 1.04 XXX 1..26 XXXI l. * 7 XXXII 1.43 XXXIII 1.46 XXXIV 1.40

greater veil on storage '

greater veil on storage

larger veil at storage

less haze on storage

less haze on storage

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The numerical values given in the table, especially for the sensitivity, clearly show the superiority of the oxacarbocyanine and benzimldazolocarbocyanine dyes over, for example, styryl, cyanine and, in particular, merocyanine dyes when these dyes are used in silver halide emulsions which are identical. In this case, 1st particularly emphasized that the other sensitometriechen properties when using Oxacarbocyanin- or Benzimldazolocarbocyaninfarbstoffen be deteriorated in the emulsions in any case.

Highly sensitive, spectrally sensitized photographic emulsions of the type according to the invention are not only suitable for the production of a wide variety of lithographic plates, but also, for example, for plates to be produced by photographic transfer processes, as described in Examples 7 to 9 of US Pat. No. 3,146,104, and finally also for positive -positive working method sur production of lithographic printing plates, as will be described in the following example, the large difference in sensitivity is exploited between a with a Oxacarbocyaninfarbstoff and with a Thiacarbocyaninfarbstoff sensi-stabilized photographic material.

Example 5

For comparison purposes, one of Dye No. III * Bei · 4 game and the other time the dye no. XXIII of Example

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BATH O.

4 was added to the same fine grain silver chloride emulsion, whereupon both emulsions were exposed and developed in the same way became. The sensitivity determined for the emulsion sensitized with Dye No. III would be a numerical value of 100 assigned. The relative sensitivity of the emulsion sensitized with Dye No. XXIII was then given a Received value of 2510. That is, the silver chloride emulsion containing the oxacarbocyanine dye is 25 times more sensitive than the same emulsion containing the thiacarbocyanine dye. This sizeable difference in sensitivity became the result used to make a positive-positive working lithographic printing plate.

A paper support was coated with a gelatin-silver chloride emulsion prepared with Dye No. III of Example 4 was sensitized and the developer compound 4-phenylpyrocatechln contained. The emulsion was applied in such a way that about 50 g gelatin, 20 g silver (as silver chloride) and 4 g of the developer compound were omitted, A similar silver chloride emulsion was then passed over this emulsion layer applied, but their binding agent consists mainly of alkali-soluble, acid-insoluble cellulose ether phthalate and for which Dye No. XXIII of Example 4 was used as the sensitizing dye. This far The more sensitive emulsion was applied in such a way that 28 g of binder and 30 g of silver were used on about 9 square meters of support surface.

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This photographic material was exposed imagewise in such a way that a latent image was formed only in the upper, more sensitive emulsion layer, and this was then developed into a (visible) negative image with a normal p-methylaminophenol hydroquinone developer. The material was then flashed (through the negative image) and then treated with a solution containing 4% sodium carbonate, monohydrate, whereby the positive areas of the lower silver halide emulsion layer were developed to be tanned by the 4-phenylcatechol contained therein. If the material was finally washed with water, the upper (negative) emulsion layer peeled off and a positive, oleophilic image pattern remained on the surface of the lower emulsion layer, which was then colored. Positive prints of the original could be obtained from the printing plate obtained on a lithographic press.

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Claims (4)

Claims 1. Process for making lithographic printing plates by photographic means, in which a photographic material consisting of a support and a non-fogged sensitized gelatin-silver halide emulsion layer applied thereon, and optionally an intermediate layer between the support and the emulsion layer as well as a further veiled gelatin-silver halide emulsion layer applied over the non-veiled layer, the outer emulsion layer of which has a hardness such as a gelatin layer hardened with about 4.4 to 33 g formaldehyde (100 Ji) per kg gelatin, imagewise exposed and in the presence a polyoxybenzene developing agent, is developed with an alkaline solution, characterized in that a material is used whose unveiled silver halide emulsion layer with at least an oxacarbocyanine and / or benzimldazole carbocyariine dye is sensitized. 2. Photographic material for carrying out the process according to Claim 1, consisting of a support, a gelatin layer applied thereon, containing a polyoxybenzene developer compound, and a non-flaked gelatin-silver halide layer which has a hardness corresponding to one with . about 4.4 hardened to 33 g of formaldehyde (100%) per kg of gelatin aelatineschicht has, _β characterized oils that 909882/0990 Emulsion layer with at least one oxacarbocyanine and / or benzimidazole carbocyanine dye of the general formulas: QC = CH-C-CH-C _Λ Q '* X "or "3 R ₁ R ₂ A t C = CH-C-CH-C .Π Q '* X' "3 V R ₁ ^ R ₂ where mean: Q and Q ¹ each to complete a phenyl ring required atomic groups; R ₁ and R ₂ each represent an alkyl group; R, a hydrogen atom, a lower alkyl group or an aryl group; Y is an oxygen, sulfur, nitrogen or selenium atom; Z is a = C "" ¹ ^ or = NRg group, in which R ₁ ^, R, - and Rg consist of lower alkyl groups; A is an alkyl group and X is an anion, is sensitized. BATH ORIGINAL 909882 / 099G 3. Photographic material for carrying out the method according to claim 1, consisting of a support, applied thereon, a gelatin layer containing a polyoxybenzene compound, a non-fogged gelatin-silver halide emulsion layer applied thereon and a fogged gelatin-silver halide emulsion layer applied thereon, the hardness of which is about 4.4 corresponds to up to 33 g formaldehyde (100 %) per kg gelatin hardened gelatin layer, characterized in that the non-fogged emulsion layer contains at least one oxacarbocyanine and / or benzimidazole carbocyanine dye of the general formulas: QC = CH-C-CH-C _Λ \\ Q '* X or, \ An / l NSA ι 3 Q Π C = CH-C-CH-C _x HQ · 'X ^V "" ^R 3 R ₁ R ₂ where mean: Q and Q ¹ each serve to complete a phenyl ring required atomic groups; R ₁ and R ₂ each represent an alkyl group;
R, a hydrogen atom, a lower alkyl group or an ary group; 909882/0990 an oxygen, sulfur, nitrogen or selenium atom;
a = C or = NR, group, in which Rh, Rj- and Rg consist of lower alkyl groups; A is an alkyl group and
Χ ^θ an anion, is sensitized. 4. Photographic material according to claims 2 and 3 »characterized in that the non-fogged silver halide emulsion layer is anhydro-1-carboxyraethyl-5, o-dichloro-S-ethyl-l ', 3'» 3'-trimethylbenzimidazoloindocarbocyanine hydroxide; Anhydro-5,5'-6,6'-tetrachloro-1,1 ^f -diäthyl-3 '3'-di (3-sulfobutyl) benzimidazolcarbocyaninhydroxyd; 5,5'-dichloro-9-ethyl-3 »3'-di (3-sulfopropyl) oxacarbocyanine hydroxide; Anhydro-5-chloro-9-ethyl-5 ^l -phenyl-3 ^l - (3-sulfobutyl) -3- (3-sulfopropyl) -oxacarbbcyaninhydrojcyd or anhydro-9-ethyl-5,5'-dimethoxy-3,3 Contains' -diO-sulfopropyljoxacarbocyanine hydroxide. OFuGiNAl 909882/0990