EP0001617B1 - Diazotype material - Google Patents

Description

The invention relates to a diazo material with a diazo component and a coupling component that provides a black color image in the light-sensitive layer.

Diazotype materials consist of a layer support and a photosensitive layer applied thereon, comprising essentially a diazo component and a coupling component, which can be coupled together to form an azo dye. If such a material is exposed through an original, the diazo component is destroyed at the points hit by the radiation. Subsequent treatment of the latent copy obtained with a basic medium such as moist ammonia gas, dry ammonia gas or alkaline solution results in the coupling reaction of the undestroyed diazo with the coupling component, the azo dye being produced in the unexposed areas in accordance with the template.

While hitherto mainly diazotype materials were used which, after image-wise exposure and subsequent development, gave copies with blue or purple shades of color, the requirement now is to create diazotype materials with which copies can be made with black shades, as far as possible those known from photography are comparable.

For example, DE-B-19 23 115 discloses a two-component diazo material that provides a black color image during wet development. The material contains two coupling components in the photosensitive layer, one of which couples to a blue dye when used alone and the other to a yellow dye when used alone. 4-Diazo-2,5-dialkoxy-phenylmorpholine is used as the diazo component and a substituted 2-hydroxy-3-naphthoic acid - N "." - amino-alkyl) - amide in combination with a 1 - biguanidino - naphthol as the blue coupling component An acetoacetamide is used as the yellow coupler.

It is also known from DE-B-17 72 980 to use a multicomponent diazotype material for the production of black copies, which as a diazo component is a 4-morpholinobenzene or a 2,5-dialkoxy-4-morpholinobenzene diazonium salt in addition to blue and yellow couplers Contains coupling component.

The known black copying diazo materials can generally be used to produce copies with satisfactory sensitometric and application properties. However, when developing these materials according to the different processes used today in blueprint technology, such as development with moist ammonia gas, development with dry ammonia gas under pressure and development with alkaline solutions at different temperatures, there are sometimes considerable color differences when developing the same material. So you get e.g. in conventional development with moist ammonia gas at elevated temperature, copies with black tones, while in development with dry ammonia gas under pressure, copies with sepia tones are obtained. Similar hue differences can occur if such a diazo material is developed with moist ammonia gas at different temperatures. In practice, this is often the case when a diazo material is to be processed in the same development device or in different development devices at different development temperatures. In this way, copies are obtained with different shades of color and thus differences in the generation ability, the gradation and in the visual and actinic density. In terms of application technology, copies of this type are only suitable to a limited extent.

Another disadvantage of these black-line copying diazotype materials is that copies of different colors are often obtained from originals of different densities, in particular from halftone originals. Such two-tone copies are unsuitable for many applications due to their different spectral properties. This is especially the case if there is a transparent diazo copy, i.e. H. of an intermediate diazo original, one or more generation copies are to be made with the same diazo type material. If the information on the intermediate diazo copy is very small, for example in the case of a diazo microfilm copy, then there may be significant loss of detail either during the first generation of diazo, but mostly determined during the subsequent second and third generation of diazo, either through amplification or through weakening.

A process for the development of diazotype materials is also known (DE-A-23 25 999), in which the diazotype material is substituted as a 2,5-dialkoxy-4-morpholino-benzene diazonium salt as the diazo component and a combination of one substituted on the aryl radical of the carbonamide group as the coupling component Contains 2-hydroxy-3-naphthoamide and one or two yellow couplers. Substituted tetrahydroxydiphenyl sulfides or substituted tetrahydroxy-diphenyl sulfones and hydroxylphenyl derivatives of urea or thiourea are used as yellow couplers. With the imagewise exposure of originals of different densities and the subsequent development with moist ammonia gas, black color tones can be achieved within a large density range. When developing with dry ammonia gas under pressure, however, violet to sepia-colored tones are produced.

The object of the invention is to provide a diazo material with which copies can be made Have a black shade produced, which, under different development conditions, delivers copies with the same black shades as possible and with good color stability.

enthält, worin X gleich Null, =S, =SO oder =S0₂ ist, wobei die Molverhältnisse von Blau- zu Gelb- kuppler im Bereich von (0,7-0,9):1 und von Blau- zu Rotbraunkuppler im Bereich von (6-12):1 liegen. Die Molverhältnisse von Blau- zu Gelbkuppler bzw. von Blau- zu Rotbraunkuppler liegen vorzugsweise bei etwa 0,8:1 bzw. 8:1.This object is achieved by a diazotype material with a 2,5-dialkoxy-4-morpholino-benzenediazonium salt as the diazo component and a combination of a 2-hydroxy-3-naphthoic acid amide as the blue coupler, a yellow coupler and a red-brown coupler in the light-sensitive layer, which gives a black color image, which is characterized in that it is a 6-methoxy-2-hydroxy-3-naphthoic acid - N - (w - aminoalkyl) amide as a blue coupler, a 2-alkyl- or 2-aryl-1 as a yellow coupler, 3-dihydroxy-benzene or a cyanoacetamide and as a red-brown coupler a compound of the formula

contains, where X is zero, = S, = SO or = S0 ₂ , the molar ratios of blue to yellow couplers in the range from (0.7-0.9): 1 and from blue to red-brown couplers in the range of (6-12): 1. The molar ratios of blue to yellow couplers or from blue to red-brown couplers are preferably around 0.8: 1 or 8: 1.

The molar ratio of diazo component to coupling component is preferably in the range of 1: (1, 1-1.4). A molar ratio of 1: 1.3 has proven to be particularly favorable.

The result of this is that a diazotype material which is balanced in its components can be made available which, regardless of its type of development, can be copied with dark violet to bluish black, i.e. with moist or dry ammonia gas or with the aid of alkaline solution at different pressure and temperature conditions. in all black shades. The copies also have high visual contrast, a medium to flat gradation and good generation ability. Finally, the diazo material according to the invention has an excellent shelf life and can be used universally.

In a preferred embodiment, the diazo component additionally contains a 4 - (dialkylamino) benzenediazonium salt, the d-os molar ratio of 2.5 - dialkoxy - 4 - morpholinobenzene diazonium salt to 4 - (dialkylamino) benzenediazonium salt being in the range from (5 to 7): 1 . A molar ratio of about 6.5: 1 is particularly favorable.

This ensures that the dark violet to bluish black hue of the copies approaches a neutral black, a hue that is similar to that known from silver photography.

For the production of diazotype materials which lead to almost the same color tones under different development conditions, it must be ensured that the molar ratio of blue to yellow coupler is observed. Otherwise, a bluish tint is obtained with a significant increase. If the molar ratio of the blue to yellow coupler is reduced below the specified limit, the coupling is given a more yellow-greenish dark shade. The same applies if the molar ratio of blue to red-brown couplers is outside the specified limit range. Exceeding the coupling leads to greenish-blue shades, falling below violet-blue shades. Higher coupler concentrations lead e.g. to an unnecessary excess of unreacted coupling components and are therefore not appropriate. The molar ratio of diazo component to coupling component is therefore preferably in the range given above.

worin

• R einen Alkoxyrest mit 1 bis 6, insbesondere mit 2 bis 4 Kohlenstoffatomen, und
• X das Anion, z.B. ein Chlorozinkat.-, Fluoborat- oder Hexafluophosphatanion

bedeuten.The 2,5-dialkoxy -4-morpholinobenzene diazonium salts suitable for producing the light-sensitive diazotype material according to the invention can be represented by structural formula (I)

wherein

• R is an alkoxy radical having 1 to 6, in particular having 2 to 4, carbon atoms, and
• X is the anion, for example a chlorozincate, fluoborate or hexafluophosphate anion

mean.

A compound of the structural formula given, where R is n-butoxy and X as the fluoborate anion, can be used particularly advantageously.

wiedergegeben, worin

• R einen Alkylrest mit 1 bis 6, insbesondere mit 1 bis 3 Kohlenstoffatomen und
• X ein Anion der oben genannten Art

bedeuten.The 4- (dialkylamino) benzene diazonium compound is represented by structural formula (11)

reproduced in which

• R is an alkyl radical with 1 to 6, in particular with 1 to 3, carbon atoms and
• X is an anion of the type mentioned above

mean.

A compound with R equal to n-propyl and X as fluoborate anion is very particularly advantageous.

wobei

• R und R₁ gleich oder verschieden sind und Wasserstoff, einen kurzkettigen Alkylrest oder Hydroxyalkylrest mit 1 bis 8, vorzugsweise 1 bis 4, Kohlenstoffatomen, oder gemeinsam mit dem Stickstoffatom, an das sie gebunden sind, einen heterocyclischen Rest mit 5 bis 8 Ringgliedern bilden und
• n eine ganze Zahl zwischen 2 bis 5, vorzugsweise 3, bedeuten.

The blue coupler used to produce the diazotype material according to the invention is represented by the structural formula (111)

in which

• R and R _{1 are} identical or different and form hydrogen, a short-chain alkyl radical or hydroxyalkyl radical with 1 to 8, preferably 1 to 4, carbon atoms, or together with the nitrogen atom to which they are attached, form a heterocyclic radical with 5 to 8 ring members and
• n is an integer between 2 and 5, preferably 3.

worin

• R₂ Alkyl- mit 1 bis 4 Kohlenstoffatomen, insbesondere Methyl- oder Aryl-, das substituiert sein kann, insbesondere Phenylbedeutet und worin
• R₃ und R₄ gleich oder verschieden sein können und einen Alkylrest mit 1 bis 6, insbesondere 1 bis 3 Kohlenstoffatomen, gegebenenfalls substituiertes Aryl-, insbesondere Methoxyphenyl- oder Benzyl-, oder Aralkylreste, die substituiert sein können, oder gemeinsam mit dem Stickstoffatom, an das sie gebunden sind, einen heterocyclischen Rest mit 5 bis 8 Ringgliedern, insbesondere einen Morpholinrest, bilden,

darstellenThe yellow couplers used can be represented by the following structural formulas (IV) and ilVa)

wherein

• R _{2 is} alkyl with 1 to 4 carbon atoms, in particular methyl or aryl, which may be substituted, in particular phenyl and in which
• R ₃ and R _{4 may be the} same or different and an alkyl radical having 1 to 6, in particular 1 to 3, carbon atoms, optionally substituted aryl, in particular methoxyphenyl or benzyl, or aralkyl radicals, which may be substituted, or together with the nitrogen atom, to which they are attached form a heterocyclic radical with 5 to 8 ring members, in particular a morpholine radical,

represent

• Tetrahydroxy-diphenyl
• Tetrahydroxy-diphenylsulfid
• Tetrahydroxy-diphenylsulfoxid
• Tetrahydroxy-diphenylsulfon.

Examples of suitable red-brown couplers are:

• Tetrahydroxy diphenyl
• Tetrahydroxy diphenyl sulfide
• Tetrahydroxy diphenyl sulfoxide
• Tetrahydroxy diphenyl sulfone.

In a particular embodiment, the diazotype material according to the invention contains 2,5 - di - butoxy - 4 - morpholino - benzenediazonium fluoroborate and 4 - (di - propylamino) - benzenediazonium fluoroborate, 6 - methoxy - 2 - hydroxy - 3 - naphthoic acid - N (3 - morpholinopropyl) - amide, 2 - methyl - 1,3 - dihydroxy - benzene and 2,2 ', 4,4' - tetrahydroxy diphenyl sulfide.

By using a diazonium salt mixture, it is possible to control the hue from the diazo component as well. In addition to almost the same sensitivity to light, such a diazotype material is characterized by its insensitivity to different development processes and development conditions. Copies made with this material develop into practically the same color, completely neutral black shades.

The diazonium salts and coupling components used are known, customary compounds. The diazo composition is usually applied to the support in the form of a solution of the individual components in a solvent or a solvent mixture. After drying, the photosensitive obtained can then Layer are exposed imagewise in a known manner and developed.

Water, isopropanol, butanol, acetone, methanol, 2-methoxyethyl acetate, glycol monomethyl ether and glycol monoethyl ether serve as suitable solvents.

The diazotype constituents are preferably applied to the layer support from organic medium which contains a film-forming binder. The concentration of the azo dye-forming constituents in the binder can vary between approximately 15 and 30 parts by weight per 100 parts by weight of binder.

Examples of suitable binders are cellulose ethers, such as ethyl cellulose, cellulose esters, such as cellulose acetate, triacetate, acetopropionate, butyrate and acetobutyrate, vinyl polymers, such as polyvinyl acetate, polyvinylidene chloride, vinyl chloride / vinyl acetate copolymers, poly (methyl methacrylate) and alkylactic methyl acrylate Acrylic acid or polyphenylene oxides or ethylene glycol / isophthalic acid RE erephthalic acid terpolymers.

In addition to the dye-forming constituents, the light-sensitive layer can also contain acidic stabilizers and other diazotype auxiliaries.

Suitable acidic stabilizers which prevent the diazonium salts from coupling too early with the coupling components are organic acids such as 5-sulfosalicylic acid. Such organic acids used for stabilization are preferably used in concentrations of about 4-8 parts by weight per 100 parts by weight of binder. In addition, metal salts, e.g. Zinc chloride, which, in addition to their stabilizing effect, contribute in particular to improving the contrast of the developed copy. In addition, substances that accelerate development are added to the light-sensitive layer. Such substances are e.g. Carboxylic acid esters from aliphatic and aromatic mono- or dicarboxylic acids and monohydric low-aliphatic alcohols, and esters from carboxylic acids and polyhydric aliphatic alcohols. Preferably the glycerol esters of lower aliphatic acids, e.g. Glycerol and glycerol triacetate used. Furthermore, hygroscopic agents such as glycol, glycerin etc. can be used to regulate the moisture balance in the light-sensitive layer and to improve the exposed areas of the copy, suitable dyes in a low concentration, e.g. Methyl violet can be added. In addition, so-called "anti-yellowing agents", e.g. Thiourea or thiourea derivatives can be added. In order to improve the sliding properties of overlying unexposed or developed copying materials, inorganic fine-particle pigments are used as so-called "slip agents", e.g. Silicic acid, aluminum oxide etc. added.

Suitable supports for the light-sensitive layers are all customary support materials, e.g. coated or uncoated opaque and transparent paper, textiles, cellulose esters such as cellulose 2 1/2 and cellulose triacetate, polyesters such as polyethylene terephthalate, vinyl polymers such as polyvinyl acetate or polystyrene. If necessary, however, the light-sensitive layer can also be a self-supporting layer, i.e. it is not absolutely necessary for the coating composition to be adhered to a layer support.

It has proven to be expedient to apply the coating to the support in such a way that a visual optical density of about 1-2.5 is achieved after the development of the light-sensitive layer. If the visual optical density is less than 1.0, the diazo material produced in this way generally provides copies with only a low contrast, which is insufficient for practical use. On the other hand, if the visual optical density is above 2.5, such a diazotype material is usually too light-insensitive and, after image-wise exposure and development, also provides copies with too high a contrast, so that if the support is transparent, the generation capacity of these diazocopies is very limited is.

The following examples are intended to explain the invention in more detail.

Examples Annotation:

A. A basecoat (BL) of 7.5% cellulose acetopropionate in a mixture of acetone, methanol, butanol and glycol monomethyl ether is used for the diazotype materials produced in the examples.

B. The diazo materials produced according to the examples are developed using three different development processes (EV 1-EV 3) and the color shades obtained are assessed visually for comparison. EV 1 is the development with moist ammonia gas at 60-70 ° C, EV 2 is the development with dry ammonia gas under pressure at 20-25 ° C and EV 3 is the development with an alkaline developer solution at 40-45 ° C (bath development) is displayed. The alkaline developer solution (EL) consists of ethanolamine, water and an alkylphenol polyglycol ether as a wetting agent.

example 1

6 different coating solutions with the following composition are produced:

• 6 - Methoxy - 2 - hydroxy - 3 - naphthoesäure - N(3 - morpholinopropyl) - amid (BK 1)
• 2 - Hydroxy - 3 - naphthoesäure - N(3 - morpholinopropyl) - amid (BK 2)
• 2 - Hydroxy - 3 - naphthoesäure - N(2 - methylphenyl) - amid (BK 3)
• 2 - Hydroxy - 3 - naphthoesäure - N(2 - methoxyphenyl) - amid (BK 4)
• 2 - Hydroxy - 3 - naphthoesäure - N(2,4 - dimethoxy - 5 - chlorphenyl) - amid (BK 5)
• 6 - Brom - 2 - hydroxy - 3 - naphthoesäure - N(3 - morpholinopropyl) - amid (BK 6)

Substances known as such are used as blue couplers in the solutions:

• 6 - methoxy - 2 - hydroxy - 3 - naphthoic acid - N (3 - morpholinopropyl) - amide (BK 1)
• 2 - hydroxy - 3 - naphthoic acid - N (3 - morpholinopropyl) - amide (BK 2)
• 2-hydroxy-3-naphthoic acid - N (2-methylphenyl) amide (BK 3)
• 2 - hydroxy - 3 - naphthoic acid - N (2 - methoxyphenyl) - amide (BK 4)
• 2 - hydroxy - 3 - naphthoic acid - N (2,4 - dimethoxy - 5 - chlorophenyl) - amide (BK 5)
• 6 - bromo - 2 - hydroxy - 3 - naphthoic acid - N (3 - morpholinopropyl) - amide (BK 6)

Each of the solutions is then applied to a polyethylene terephthalate support provided with an adhesive layer in such a way that, after drying, the diazotype materials obtained can develop to an optical solid density of approximately 1.8-2.0, measured using a green filter (Kodak Wratten NR 93) .

The solids content of the individual solutions is between 8.5 and 9.0 percent by weight.

Of the diazo materials produced in this way, a first section is developed according to the development process EV 1, a second section according to the development process EV 2 and a third section according to the development process EV 3. The color tones achieved are assessed visually in transmitted light.

From the data compiled in the table it follows that only when the combination of diazonium salt, blue, yellow and red-brown coupler according to the invention is used does the diazotype material according to solution 1 develop to the same bluish black dyes in the 3 different development processes.

• - morpholinoäthyl,
• - morpholinopentyl,
• - pyrrolidinoäthyl,
• - diäthylaminoäthyl,
• - hydroxyäthylaminoäthyl und
• - aminoäthyl.

Similar. good results are achieved if the blue coupler type BK 1 is used, in which the basic morpholinopropyl radical is replaced by radicals such as

• - morpholinoethyl,
• - morpholinopentyl,
• pyrrolidinoethyl,
• - diethylaminoethyl,
• - hydroxyethylaminoethyl and
• - aminoethyl.

• Äthoxy,
• Trifluoromethyl,
• Carbonamid,
• Sulfamid,
• Nitro,
• Dimethyl,
• Diäthylamino,
• Hydroxy oder
• Fluor bzw. Brom,

besetzt ist,
wobei im aromatischen Carbonamidrest ein Substituent oder mehrere gleiche oder verschiedene Substituenten anwesend sein können, werden keine schwarzen Farbtöne erhalten.With appropriate substitution on the blue couplers BK 2 and BK 6, none become uniform get black shades. Even if blue couplers of the type BK _' 3, 4 and 5 are used, in which the aromatic radical of the carbonamide group is passed through in addition to methyl, methoxy and chlorine

• Ethoxy,
• Trifluoromethyl,
• Carbonamide,
• Sulfamide,
• Nitro,
• Dimethyl,
• Diethylamino,
• Hydroxy or
• Fluorine or bromine,

is busy
in which one or more identical or different substituents may be present in the aromatic carbonamide radical, no black shades are obtained.

The blue couplers of type BK 1, 2 or 6 are obtained in a known manner by aminolysis of methyl 2-hydroxy-3-naphthoate or 6-methoxy- or 6-bromo-2-hydroxy-3-naphthoic acid methyl ester with the corresponding N, N- disubstituted alkylene diamines.

The blue couplers of type BK 3, 4 or 5 are obtained by known processes by aminolysis of 2-hydroxy-3-naphthoic acid chloride with the corresponding nucleus-substituted aniline derivatives.

Example 2

gelöst.

solved.

The solids content is 10 percent by weight.

As described in Example 1, the solution is applied to a polyethylene terephthalate film provided with an adhesive layer and dried. Subsequently, 3 pieces of approximately 10 cm ^{2 of} equal size are cut off from the diazo material obtained in this way and each section is exposed under a silver image template until the exposed background has a visual optical density of 0.07. Sections 1, 2 and 3, each exposed in an image, are developed according to the respective development processes EV 1, EV 2 and EV 3.

The diazo film copies produced are viewed in transmitted light for visual assessment of the color tone. It can be seen that the unexposed areas of the three diazo film sections were developed into neutral black dyes with only very slight color fluctuations.

Change the molar ratio of 2,5 - dibutoxy - 4 - morpholino - benzenediazonium fluoroborate and .4 - (dipropylamino) - benzenediazonium fluoroborate to about 1: 1 by adding 380 mg 2,5 - dibutoxy - 4 - morpholino - benzenediazonium fluoroborate and 260 mg 4 - (Dipropylamino) - benzene diazonium fluoroborate used, so you get diazocopies with brown shades. On the other hand, if the molar ratio of 2,5 - dibutoxy - 4 - morpholino - benzenediazonium fluoroborate and 4 - (dipropylamino) - benzenediazonium fluoroborate is increased to about 15: 1, diazocopies with blue shades are obtained.

Neutral black shades are also achieved in the result if, instead of 2,5 - dibutoxy - 4 - morpholino - benzenediazonium fluoroborate, 2,5 - diethoxy - 4 - morpholino - benzenediazonium fluoroborate and instead of 4 - (dipropylamino) - benzenediazonium fluoroborate 4 - (diethylamino) - uses benzenediazonium fluoroborate.

Example 3

The solids content of the solution is 10 percent by weight.

The molar ratio of blue coupler 6 - methoxy - 2 - hydroxy - 3 - naphthoic acid - N (3 - morpholinopropyl) - amide and yellow coupler 2-methylresorcinol is 0.8: 1.

The solution is applied to a polyethylene terephthalate film provided with an adhesive layer and dried.

The procedure for producing, developing and evaluating the diazo film copies is the same as in Example 2. Diazo film copies with neutral black dye images are obtained, the shades of which differ only slightly from one another.

If the molar ratio of blue coupler and yellow coupler is increased to 1.75: 1, diazocopies with reddish blue dye images are obtained.

If the molar ratio of blue coupler and yellow coupler is reduced to 0.5: 1, diazocopies with greenish brown dye images are obtained.

Similar results are obtained with neutral black dye images if the blue coupler is replaced by the type BK 1 compounds mentioned in Example 1 and the yellow coupler is replaced by 2-phenylresorcinol or cyanoacetic acid-N (4-methoxyphenyl) amide.

Example 4

In 100 n-1 basecoat BL are dissolved:

The solids content of the solution is 10 percent by weight.

The molar ratio of 6 - methoxy - 2 - hydroxy - 3 - naphthoic acid - N (3 - morpholinopropyl) amide and 2,2 ', 4,4' - tetrahydroxydiphenyl sulfide is 8: 1.

As described in Example 1, the solution is applied to a polyethylene terephthalate film provided with an adhesive layer, then dried and then, as described in Example 2. exposed and developed imagewise.

Diazofilm copies with neutral black dye images, the color shades of which differ only slightly, are obtained by the different development processes.

If the molar ratio of the blue coupler and the red-brown coupler is reduced to 4: 1, green-tinted black dye images are obtained after EV 1 and violet-tinted black dye images after EV 2 and EV 3.

If the molar ratio of blue coupler and red-brown coupler is increased to 25: 1, then after EV 1 violet-colored black and after EV 2 and EV 3 green-colored black dye images are obtained.

Similar, good results are achieved if the blue coupler is replaced by the compounds of type BK 1 mentioned in Example 1 and the red-brown coupler by 2,2 ', 4,4' - tetrahydroxy - diphenyl, 2,2 ', 4, 4 '- tetrahydroxy - diphenylsulfoxide or 2,2', 4,4 '- tetrahydroxy - diphenylsulfone can be replaced.

Example 5

Der Feststoffgehalt der Lösung beträgt 10 Gewichtsprozent.A natural transparent paper used in the diazo type is coated on one side with the following solution and dried:

The solids content of the solution is 10 percent by weight.

The solution is applied to the transparent paper support in such a way that after drying and development of the diazo layer with moist ammonia gas, a maximum visual optical density of 1.70 is achieved.

The diazo material produced in this way is exposed and developed imagewise in a commercially available blueprint device under a template.

An extremely high-contrast diazo copy with neutral black dye images is obtained. Since the dyes absorb the actinic radiation of conventional blueprint lamps very well, the diazo copy obtained is ideally suited as an intermediate original for making further diazo copies.

Example 6

A standard blueprint base paper with a primer made of colloidal silica and polyvinyl acetate was coated on the pretreated surface with a filtered solution of the following composition:

After drying, the sensitized paper was exposed imagewise under a transparent template and developed in a commercially available blueprint device with moist ammonia gas. Neutral black dye images were obtained.

Claims (4)

1. Diazotype material, comprising in the light-sensitive layer a 2,5 - dialkoxy - 4 - morpholino - benzene diazonium salt as the diazo component and a combination of a 2 - hydroxy - 3 - naphthoic acid amide as blue coupler, a yellow coupler and a reddish-brown coupler, which yields a black image, wherein the blue coupler is a 6 - methoxy - 2 - hydroxy - 3 - naphthoic acid - N - (ω - aminoalkyl) - amide, the yellow coupler is a 2-alkyl- or 2-aryl-1,3-dihydroxybenzene or a cyanoaceto- amide and the reddish-brown coupler is a compound of the formula

wherein X is zero, =S, =SO, or =S0₂, the molar ratio of blue coupler to yellow coupler being in the range of (0.7 to 0.9):1, and the molar ratio of blue coupler to reddish-brown coupler being in the range of (6 to 12):1.

2. A diazotype material as claimed in claim 1, wherein the molar ratio of diazo component to coupling component is in the range of 1:(1.1 to 1.4).

3. A diazotype material as claimed in claim 1 and claim 2, wherein the diazo component additionally contains a 4 - (dialkylamino) - benzene diazonium salt, the molar ratio of 2,5 - dialkoxy - 4 - morpholino - benzene diazonium salt to 4 - (dialkylamino) - benzene diazonium salt being in the range of (5 to 7):1.

4. A diazotype material as claimed in claims 1 to 3, which comprises in the light-sensitive layer 2,5 - dibutoxy - 4 - morpholino - benzene diazonium fluoborate, 4 - (dipropylamino) - benzene diazonium fluoborate, 6 - methoxy - 2 - hydroxy - 3 - naphthoic acid - N(3 - morpholino - propyl) - amide, 2 - methyl - 1,3 dihydroxy - benzene and 2,2', 4,4' - tetrahydroxy - diphenyl sulfide.