Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
  • G03C8/00—Diffusion transfer processes or agents therefor; Photosensitive materials for such processes
  • G03C8/24—Photosensitive materials characterised by the image-receiving section
  • G03C8/26—Image-receiving layers
  • G03C8/28—Image-receiving layers containing development nuclei or compounds forming such nuclei

Definitions

• the present invention relates to an image-receiving layer and to a method for obtaining an image therewith using the silver salt diffusion transfer method.
• DTR process The principle of the silver complex diffusion transfer process (hereinafter referred to as DTR process) is well known from the description in U.S. Pat. NO. 2,352,014 and in the book "Photographic Silver Halide Diffusion Processes” by Andre Rott and Edith Weyde - The Focal Press - London and New York, (1972).
• the silver complex is imagewise transferred by diffusion from a silver halide emulsion layer to an image receptive layer and transformed therein into a silver image generally in the presence of physical development nuclei.
• the imagewise exposed silver halide emulsion layer is arranged so as to be in contact with or is brought into contact with the image receptive layer in the presence of a developing agent and a solvent for the silver halide, thereby to convert the unexposed silver halide into a soluble silver complex.
• the silver halide In the exposed areas of the silver halide emulsion layer, the silver halide is developed into silver which is insoluble and, hence, cannot diffuse.
• the unexposed areas of the silver halide emulsion layer the silver halide is converted into a soluble silver complex and is transferred to an image receptive layer wherein the silver complex forms a silver image generally in the presence of development nuclei.
• the DTR-image can be formed in the image-receiving layer of a sheet or web material which is a separate element with respect to the photographic silver halide emulsion material (a so-called two-sheet DTR element) or in the image-receiving layer of a so-called single-support-element, also called mono-sheet element, which contains at least one photographic silver halide emulsion layer integral with an image-receiving layer in water permeable relationship therewith.
• the DTR process can be utilized in a wide field such as reproduction of documents, making of printing plates, preparation of black copies, and instant photography.
• an imaging element having a silver halide emulsion layer is brought into close contact with a positive material having an image receptive layer in a DTR processing solution generally containing a silver-complexing agent, thereby to form a silver image receptive layer of the positive material.
• the silver image in these cases is required to be pure black or bluish black in color and sufficiently high in density. It is also important that the silver image be high in contrast and sharpness, excellent in image reproducibility, and preferably high in transfer speed.
• these properties of the positive material should not be greatly dependent upon the processing conditions such as, for example, processing time and temperature.
• an image receiving material comprising an image receiving layer containing physical development nuclei characterized in that said receiving layer comprises a compound according to formula (I) below in an amount between 0.3 M g/ M 2 and 9mg/m 2 wherein Y represents the necessary atoms for completing an aromatic ring, L represents an organic divalent group, Z represents -COOM or, -SO 3 M wherein M represents hydrogen, a metal ion or NH 4 + and n may be 0 or 1.
• the quality of the obtained image using the DTR-process is improved. Especially the density, sharpness and contrast of the image are improved.
• the DTR-material according to the present invention offers the advantage that it can be used under a wide range of processing conditions. Thus the DTR-material according to the invention can be processed without substantial loss of image quality in a temperature range from 15 ° C to about 35 ° C even in processing solutions that are substantially exhausted.
• Suitable physical development nuclei for use in accordance with the present invention are those commonly employed in the DTR-process e.g. noble metal nuclei e.g. silver, palladium, gold, platinum, sulphides, selenides or tellurides of heavy metals e.g. PdS, Ag 2 S, AgNiS, CoS etc.. Preferably used are Ag 2 S or AgNiS nuclei.
• the physical development nuclei used in connection with the present invention may be prepared according to known procedures.
• the noble metal nuclei may be prepared as described in US-P-4.304.835.
• the heavy metal sulphides can be prepared by adding an aqueous solution of heavy metal ions to a solution containing sulphide ions.
• the compounds according to formula (I) may be added before, during or after preparation of the nuclei preferably before other compounds such as e.g. wetting agents are added to the coating solution containing nuclei to allow adsorption of said compounds of formula (I) to the surface of the nuclei.
• the amount of compounds according to formula (I) necessary to obtain the effect according to the invention may be lowered when the size of the physical development nuclei becomes smaller. Such is probably because upon lowering the size of the nuclei the specific surface of said nuclei is increased so that even for small amounts of compounds of formula (I) a substantial amount thereof will absorb to the surface of the nuclei which appears to be necessary to obtain the improved image qualities.
• the average diameter of the nuclei is preferably between 1 nm and 8nm, more preferably between 1 nm and 6nm and most preferably between 2nm and 5nm.
• the size of the nuclei is characterized by their average diameter such thus not mean that the nuclei are spherical.
• the diameter is meant the diameter corresponding to a sphere with equivalent volume.
• the amount of compounds of formula (I) added before, during or after preparation of the physical development nuclei is preferably not more than 9mg/m 2 because larger amounts will result in an inhibition of the nuclei for physical development probably due to too strong adsorption of said compounds to the nuclei surface.
• Examples of compounds corresponding to the above formula (I) suitable for use in accordance with the present invention are e.g. benzenes, naphtalenes, triazoles, benztriazoles, tetrazoles, imidazoles, benzimidazoles. thiazoles, benzimidazoles, oxazoles, benzoxazoles, naphtoxazoles etc. substituted with at least one substituent containing at least one -SO 3 M and/or -COOM group.
• the compounds according to formula (I) preferably also comprise a mercapto group. Specific examples are shown in table 1.
• toning agents i.e. to improve the black color of the silver image in a DTR-material
• these compounds are employed in larger amounts typically around 20mg/m 2.
• these compounds are employed in lower amounts especially when employed in amounts less than 10mg/m 2 the so called toning effect of these compounds substantially decreases and vanishes.
• these compounds may be added to the processing solution, imaging element and/or receiving element. In the latter case they are usually added to a layer in water permeable relationship with the image receiving layer rather than to the image receiving layer itself.
• the image receiving layer may be contained in an image receiving material or may be in water permeable relationship with a light sensitive silver halide emulsion layer in an imaging element.
• an image is obtained by information-wise exposing an imaging element comprising on a support e.g. a paper support or organic resin support a silver halide emulsion layer and subsequently developing said information-wise exposed imaging element in the presence of developing agent(s) and silver halide solvent(s) whilst in contact with an image receiving material comprising on a support an image receiving layer according to the invention.
• a support e.g. a paper support or organic resin support a silver halide emulsion layer
• developing agent(s) and silver halide solvent(s) whilst in contact with an image receiving material comprising on a support an image receiving layer according to the invention.
• the support of the image receiving material may be opaque or transparent, e.g. a paper support or resin support.
• the image receiving layer comprises for best imaging results the physical development nuclei in the presence of a protective hydrophilic colloid, e.g. gelatin and/or colloidal silica, polyvinyl alcohol etc..
• a protective hydrophilic colloid e.g. gelatin and/or colloidal silica, polyvinyl alcohol etc.
• DTR-positive materials now available on the market are composed of two or even three layers. Such materials normally contain on top of the nuclei containing layer a layer which itself contains no nuclei and otherwise has the same composition as the nuclei containing layer and mainly serves to ensure good contact between the negative and positive material during transfer. Moreover, after drying this layer provides a protective coating for the image receiving layer containing the silver image. It further prevents bronzing or plumming of the black image areas in preventing the protruding of silver from the image receiving layer in the form of a glossy silver mirror (ref. the above mentioned book p. 50).
• the processing liquid and/or the image-receiving element contains at least one image toning agent.
• the image toning agent(s) may gradually transfer by diffusion from said image-receiving element into the processing liquid and keep therein the concentration of said agents almost steady.
• silver image toning agents are in the class of phenyl substituted mercaptotriazoles, a preferred representative of which corresponds to the following structural formula :
• Still further toning agents suitable for use in accordance with the present invention are the toning agents described in the European patent applications 218752, 208346, 218753 and US-P-4683189.
• a hydrophilic colloid layer in waterpermeable relationship with the development nuclei containing layer or a back layer at the side of the support opposite to that carrying the image receiving layer contains at least part of the silver image toning agents.
• Such procedure results actually in automatic replenishment of toning agent in the processing liquid.
• At least a part of said silver image toning agents is present in the silver halide emulsion material to be developed.
• at least one of the image toning agents may be used in a hydrophilic waterpermeable colloid layer, e.g. antihalation layer at the side of the support opposite to the side coated with a silver halide emulsion layer or between the support and the silver halide emulsion layer.
• the coverage of said silver image toning agents in said antihalation layer is preferably in the range of 10 mg/m 2 to 100 mg/m 2 .
• the transfer behaviour of the complexed silver largely depends on the thickness of the image-receiving layer and the kind of binding agent or mixture of binding agents used in the nuclei containing layer.
• the reduction of the silver salts diffusing into the image receiving layer must take place rapidly before lateral diffusion becomes substantial.
• An image-receiving material satisfying said purpose is described in US-4,859,566.
• An image-receiving material of this type is very suitable for use in accordance with the present invention and contains a water-impermeable support coated with (1) an image-receiving layer according to the invention containing physical development nuclei dispersed in a waterpermeable binder and (2) a waterpermeable top layer free from development nuclei and containing a hydrophilic colloid, in such a way that :
• the coating of said layers proceeds preferably with slide hopper coater or curtain coater known to those skilled in the art.
• a white appearance of the image background even when a yellow stain should appear on storage is obtained by incorporation of optical brightening agents in the support, image-receiving layer and/or interlayer between the support and the image-receiving layer.
• the nuclei containing layer (1) is present on a nuclei-free underlying hydrophilic colloid undercoat layer or undercoat layer system having a coverage in the range of 0.1 to 1 g/m 2 of hydrophilic colloid, the total solids coverage of layers (1) and (2) together with the undercoat being at most 2 g/m 2 .
• the undercoat optionally incorporates substances that improve the image quality, e.g. incorporates a substance improving the image-tone or the whiteness of the image background.
• the undercoat may contain a fluorescent substance, silver complexing agent(s) and/or development inhibitor releasing compounds known for improving image sharpness.
• the image-receiving layer (1) is applied on an undercoat playing the role of a timing layer in association with an acidic layer serving for the neutralization of alkali of the image-receiving layer.
• a timing layer By the timing layer the time before neutralization occurs is established, at least in part, by the time it takes for the alkaline processing composition to penetrate through the timing layer.
• Materials suitable for neutralizing layers and timing layers are disclosed in Research Disclosure July 1974, item 12331 and July 1975, item 13525.
• gelatin is used preferably as hydrophilic colloid.
• gelatin is present preferably for at least 60 % by weight and is optionally used in conjunction with an other hydrophilic colloid, e.g. polyvinyl alcohol, cellulose derivatives, preferably carboxymethyl cellulose, dextran, gallactomannans, alginic acid derivatives, e.g. alginic acid sodium salt and/or watersoluble polyacrylamides.
• Said other hydrophilic colloid may be used also in the top layer for at most 10 % by weight and in the undercoat in an amount lower than the gelatin content.
• the image-receiving layer and/or a hydrophilic colloid layer in water-permeable relationship therewith may comprise a silver halide developing agent and/or silver halide solvent, e.g. sodium thiosulphate in an amount of approximately 0.1 g to approximately 4 g per m 2 .
• a silver halide developing agent and/or silver halide solvent e.g. sodium thiosulphate in an amount of approximately 0.1 g to approximately 4 g per m 2 .
• the image-receiving layer or a hydrophilic colloid layer in water-permeable relationship therewith may comprise colloidal silica.
• the image-receiving layer may contain as physical development accelerators, in operative contact with the developing nuclei, thioether compounds such as those described e.g. in DE-A-1,124,354; US-A-4,013,471; US-A-4,072,526; and in EP 26520.
• an optical brightening agent in the image-receiving material preference is given to an optical brightening agent that is inherently by its structure resistant to diffusion or is made resistant to diffusion by use in conjunction with another substance wherein it is dissolved or whereto it is adsorbed.
• the optical brightening compound is substituted with a long chain aliphatic residue and ionomeric residue as is known in the synthesis of diffusion resistant colour couplers.
• an optical brightening agent of the oleophilic type is incorporated in droplets of a water-immiscible solvent, so-called “oilformer”, e.g. dibutylphthalate.
• the optical brightening agent is used in conjunction with a polymeric hydrophilic colloid adsorber, a so-called trapping agent, e.g. poly-N-vinylpyrrolidinone as described e.g. in US-P 3,650,752, 3,666,470 and 3,860,427 and published European patent application 0 106 690.
• a trapping agent e.g. poly-N-vinylpyrrolidinone as described e.g. in US-P 3,650,752, 3,666,470 and 3,860,427 and published European patent application 0 106 690.
• latex compositions are used wherein latex particles are loaded, i.e. contain in dissolved and/or adsorbed state an optical brightening agent as described e.g. in German Offenlegungsschrift (DE-OS) 1,597,467 and in US-P 4,388,403.
• DE-OS German Offenlegungsschrift
• the image-receiving layer and/or other hydrophilic colloid layer of an image-receiving material used in a DTR-process according to the present invention may have been hardened to some extent to achieve enhanced mechanical strength.
• Appropriate hardening agents for hardening the natural and/or synthetic hydrophilic colloid binding agents in the image-receiving layer include e.g. formaldehyde, glyoxal, mucoch- loric acid, and chrome alum.
• Other suitable hardening agents for hardening the hydrophilic colloid binding agents in the image-receiving layer are vinylsulphonyl hardeners, e.g. as described in Research Disclosure 22,507 of Jan. 1983.
• hardening is effected by incorporating a hardener precursor in the image-receiving layer, the hardening of the hydrophilic colloid therein being triggered by the treatment with an alkaline processing liquid during processing.
• the image-receiving material can be used in the form of roll film or sheet film or in the form of a filmpack e.g., for in-camera-processing.
• the image-receiving material can be used in conjunction with any type of photographic silver halide emulsion material suited for use in diffusion transfer reversal processing.
• the silver halide emulsion material may contain one or more hydrophilic colloid - silver halide emulsion layers.
• the hydrophilic colloid silver halide emulsion layer can be coated from any photosensitive silver halide emulsion comprising a hydrophilic colloid binder, which usually is gelatin.
• a hydrophilic colloid binder which usually is gelatin.
• use can be made of one or more other natural and/or synthetic hydrophilic colloids, e.g. albumin, casein, zein, polyvinyl alcohol, alginic acids or salts thereof, cellulose derivatives such as carboxymethyl cellulose, modified gelatin, e.g. phthaloyl gelatin etc.
• the weight ratio of hydrophilic colloid binder to silver halide expressed as equivalent amount of silver nitrate to binder is e.g. in the range of 1:1 to 10:1.
• the total amount of binder contained on the photosensitive side of the imaging element is preferably between 4g/m 2 and 9g/m 2 , most preferably between 6 and 8g/m 2 while the amount of liquid taken up by the imaging element when soaked for 1 min. in a 0.1 N aqueous solution of NaOH is preferably between 3.5ml for 1 binder and 7ml for 1 g binder.
• the photosensitive silver halide used in the present invention may comprise silver chloride, silver bromide, silver bromoiodide, silver chlorobromoiodide and the like, or mixtures thereof.
• a silver halide emulsion mainly comprising silver chloride is used preferably.
• This silver chloride emulsion may comprise utpo 40mole% preferably upto 20 mole% of silver bromide and/or upto 2% preferably upto 0.5% of silver iodide.
• the silver iodide is preferably contained on the surface of the silver halide grains.
• the silver halide emulsions may be coarse or fine grain and can be prepared by any of the well known procedures e.g. single jet emulsions, double jet emulsions such as Lippmann emulsions, ammoniacal emulsions, thiocyanate- or thioether-ripened emulsions such as those described in US-A 2,222,264, 3,320,069, and 3,271,157.
• Surface image emulsions may be used or internal image emulsions may be used such as those described in US-A 2,592,250, 3,206,313, and 3,447,927. If desired, mixtures of surface and internal image emulsions may be used as described in US-A 2,996,382.
• the silver halide particles of the photographic emulsions may have a regular crystalline form such as cubic or octahedral form or they may have a transition form. Regular-grain emulsions are described e.g. in J. Photogr. Sci., Vol. 12, No. 5, Sept./Oct. 1964, pp. 242-251.
• the silver halide grains may also have an almost spherical form or they may have a tabular form (so-called T-grains), or may have composite crystal forms comprising a mixture of regular and irregular crystalline forms.
• the silver halide grains may have a multilayered structure having a core and shell of different halide composition. Besides having a differently composed core and shell the silver halide grains may comprise also different halide compositions and metal dopants inbetween.
• Two or more types of silver halide emulsions that have been prepared differently can be mixed for forming a photographic emulsion for use in a photographic material treated with a processing liquid according to the present invention.
• the average size expressed as the average diameter of an equivalent sphere of the silver halide grains may range from 0.2 to 1.2 I .Lm, preferably between 0.2 ⁇ m and 0.8tim, and most preferably between 0.3 ⁇ m and 0.6tim.
• the size distribution can be homodisperse or heterodispere. A homodisperse size distribution is obtained when 95 % of the grains have a size that does not deviate more than 30 % from the average grain size.
• the emulsions can be chemically sensitized e.g. by adding sulphur-containing compounds during the chemical ripening stage e.g. allyl isothiocyanate, allyl thiourea, and sodium thiosulphate.
• reducing agents e.g. the tin compounds described in BE-A 493,464 and 568,687, and polyamines such as diethylene triamine or derivatives of aminomethane-sulphonic acid can be used as chemical sensitizers.
• Other suitable chemical sensitizers are noble metals and noble metal compounds such as gold, platinum, palladium, iridium, ruthenium and rhodium. This method of chemical sensitization has been described in the article of R.KOSLOWSKY, Z. Wiss. Photogr. Photophys. Photochem. 46, 65-72 (1951).
• the emulsions can also be sensitized with polyalkylene oxide derivatives, e.g. with polyethylene oxide having a molecular weight of 1000 to 20,000, or with condensation products of alkylene oxides and aliphatic alcohols, glycols, cyclic dehydration products of hexitols, alkyl-substituted phenols, aliphatic carboxylic acids, aliphatic amines, aliphatic diamines and amides.
• the condensation products have a molecular weight of at least 700, preferably of more than 1000. It is also possible to combine these sensitizers with each other as described in BE-A 537,278 and GB-A 727,982.
• the spectral photosensitivity of the silver halide can be adjusted by proper spectral sensitization by means of the usual mono- or polymethine dyes such as acidic or basic cyanines, hemicyanines, oxonols, hemioxonols, styryl dyes or others, also tri- or polynuclear methine dyes e.g. rhodacyanines or neocyanines.
• Such spectral sensitizers have been described by e.g. F.M. HAMER in "The Cyanine Dyes and Related Compounds" (1964) Interscience Publishers, John Wiley & Sons, New York.
• the silver halide emulsions may contain the usual stabilizers e.g. homopolar or salt-like compounds of mercury with aromatic or heterocyclic rings such as mercaptotriazoles, simple mercury salts, sulphonium mercury double salts and other mercury compounds.
• suitable stabilizers are azaindenes, preferably tetra- or penta-azaindenes, especially those substituted with hydroxy or amino groups. Compounds of this kind have been described by BIRR in Z. Wiss. Photogr. Photophys. Photochem. 47, 2-27 (1952).
• Other suitable stabilizers are i.a. heterocyclic mercapto compounds e.g. phenylmercaptotetrazole, quaternary benzothiazole derivatives, and benzotriazole.
• the silver halide emulsions may further contain either or not in combination with one or more developing agents pH controlling ingredients, and other ingredients such as antifogging agents, development accelerators, wetting agents, and hardening agents for gelatin.
• the silver halide emulsion layer may comprise light-screening dyes that absorb scattering light and thus promote the image sharpness and, as a consequence thereof, the sharpness of the final printed copy.
• Light-absorbing dyes that can be used as light-screening dyes have been described in i.a. US-A 4,092,168, US-A 4,311,787, DE-A 2,453,217, and GB-A 7,907,440. More details about the composition, preparation and coating of silver halide emulsions can be found in e.g. Product Licensing Index, Vol. 92, December 1971, publication 9232, p. 107-109.
• the silver halide emulsion may consist of a first light-sensitive silver halide emulsion in which a normal latent image is formed upon image-wise exposure and a second silver halide emulsion whose speed is so low that no or almost no latent image is formed therein.
• the low-speed silver halide emulsion and the light-sensitive silver halide emulsion are coated to form different layers, the resulting emulsion layers are arranged in DTR-processing in such a way that the low-speed emulsion is remotest from the image-receiving layer. It is also possible to coat one single layer comprising a mixture of both types of emulsion.
• a silver image having an enhanced contrast can be obtained.
• a silver image is formed in the image-receiving layer from the additionally obtained silver complexes in the low-speed emulsion layer.
• No image-background staining in the DTR-print takes place because the reduced silver of the light-sensitive emulsion forms a barrier for silver halide or complexes of the low-speed emulsion that would also tend to migrate towards the image-receiving element.
• the silver halide or complexes thereof diffusing from both the light-sensitive emulsion and the low-speed emulsion together build up said strenghtened high-contrast silver image in the image receiving layer.
• the low-speed emulsion may be a pure silver chloride emulsion or an emulsion of mixed silver halides comprising silver chloride e.g. a silver chlorobromide or chlorobromoiodide emulsion.
• the low-speed emulsion is preferably a silver chloride emulsion for the greater part.
• a fine-grain silver chloride having a particle size in the range of 50 to 500 nm is used.
• the amount of low-speed emulsion may vary within wide limits. Favourable results can be obtained when the ratio of low-speed silver chloride-containing emulsion to image-forming emulsion, expressed in parts by weight of silver nitrate, ranges from 10:1 to 1:1.
• the amount of low-speed emulsion to be added depends i.a. on its own nature, on the type of image-forming emulsion used, and on the effect desired. It can be determined easily by routineers in the art by making a few comparative tests.
• direct-positive emulsions of the type described in US-A 3,062,651 may be employed.
• a non-hardening fogging agent such as stannous chloride and formamidine sulphinic acid can be used.
• the silver halide emulsion coated side of the photographic material can be provided with a top layer that contains hydrophilic colloids that form a waterpermeable layer.
• a top layer that contains hydrophilic colloids that form a waterpermeable layer.
• Such top layer is usually free of gelatin. Its nature is such that it does not inhibit or restrain the diffusion transfer of the complexed silver but acts e.g. as an anti-stress layer.
• Appropriate hydrophilic binding agents for such top layer are e.g.
• methyl cellulose the sodium salt of carboxymethyl cellulose, hydroxyethyl cellulose, hydroxyethyl starch, hydroxypropyl starch, sodium alginate, gum tragacanth, starch, polyvinyl alcohol, polyacrylic acid, polyacrylamide, poly-N-vinyl pyrrolidinone, polyoxyethylene, and copoly(methylvinylether/maleic acid).
• the thickness of this layer depends on the nature of the colloid used and the required mechanical strength. Such layer if present may be transferred at least partially to the image-receiving layer without deleterious action on the image formation.
• the imaging element of the present embodiment may contain other additional layers in water permeable relationship with the silver halide emulsion layer. It is especially advantageous to include a base-layer between the support and the photosensitive silver halide emulsion layer.
• said base-layer serves as an antihalation layer so that the reflectance of the support containing said anithalation layer is not more than 25% and preferably not more than 15%.
• This layer can therefore contain the same light-absorbing dyes as described above for the emulsion layer ; as alternative finely divided carbon black can be used for the same antihalation purposes as described in US-P 2,327,828.
• the support it self may be selected such that it can serve as antihaltion means as described in e.g.
• light reflecting pigments e.g. titaniumdiox- ide
• this layer can contain hardening agents, matting agents. e.g. silica particles, and wetting agents. At least part of these mating agents and/or light reflection pigments may also be present in the silver halide emulsion layer the most part however preferably being present in said base-layer.
• the light reflecting pigments may be present in a separate layer provided between the antihalation layer and the photosensitive silver halide emulsion layer.
• alkaline processing liquid having a pH preferably between 9 and 13.
• the pH of the alkaline processing liquid may be established using various alkaline substances. Suitable alkaline substances are inorganic alkali e.g. sodium hydroxide, potassium carbonate or alkanolamines or mixtures thereof. Preferably used alkanolamines are tertiary alkanolamines e.g. those described in EP-A-397925, EP-A-397926, EP-A-397927, EP-A-398435 and US-P-4.632.896.
• a combination of alkanolamines having both a pk a above or below 9 or a combination of alkanolamines whereof at least one has a pk a above 9 and another having a pk a of 9 or less may also be used as disclosed in the Japanese patent applications laid open to the public numbers 73949/61, 73953/61, 169841/61, 212670/60, 73950/61, 73952/61, 102644/61, 226647/63, 229453/63, US-P-4,362,811, US-P-4,568,634 etc.
• the concentration of these alkanolamines is preferably from 0.1 mol/I to 0.9 mol/I. Especially good results are obtained in accordance with the present invention when one or more alkanolamines are used in the alkaline processing liquid.
• Suitable developing agents for the exposed silver halide are e.g. hydroquinone-type and 1-phenyl-3-pyrazolidone-type developing agents as well as p-monomethylaminophenol and derivatives thereof.
• a hydroquinone-type and 1-phenyl-3-pyrazolidone-type developing agent whereby the latter is preferably incorporated in one of the layers comprised on the support of the photographic material.
• a preferred class of 1-phenyl-3-pyrazolidone-type developing agents is disclosed in the European patent application number 449340.
• Other type of developing agents suitable for use in accordance with the present invention are reductones e.g. ascorbic acid derivatives. Such type of developing agents are disclosed in the European patent application number 498968.
• the developing agent or a mixture of developing agents can be present in an alkaline processing solution, in the photographic material or the receiving layer.
• the processing solution can be merely an aqueous alkaline solution that initiates and activates the development.
• the imaging element is developed in the presence of a silver halide solvent.
• a silver halide solvent Preferably used silver halide solvents are water soluble thiosulphate compounds such as ammonium and sodium thiosulphate, or ammonium and alkali metal thiocyanates.
• Other useful silver halide solvents are described in the book "The Theory of the Photographic Process” edited by T.H. James, 4th edition, p. 474-475 (1977), in particular sulphites and uracil.
• Further interesting silver halide complexing agents are cyclic imides, preferably combined with alkanolamines, as described in US 4,297,430 and US 4,355,090.
• 2-mercaptobenzoic acid derivatives are described as silver halide solvents in US 4,297,429, preferably combined with alkanolamines or with cyclic imides and alkanolamines.
• Dialkylmethylenedisulfones can also be used as silver halide solvent.
• the silver halide solvent is preferably present in the processing solution but may also be present in one or more layers comprised on the support of the imaging element and/or receiving material.
• the silver halide solvent When the silver halide solvent is incorporated in the photographic material it may be incorporated as a silver halide solvent precursor as disclosed in e.g. Japanese published unexamined patent applications no. 15247/59 and 271345/63, US-P-4,693,955 and US-P-3,685,991.
• the processing solution may comprise other additives such as e.g. thickeners, preservatives, detergents e.g. acetylenic detergents such as surfynol 104, surfynol 465, surfynol 440 etc. all available from Air Reduction Chemical Company New York.
• additives such as e.g. thickeners, preservatives, detergents e.g. acetylenic detergents such as surfynol 104, surfynol 465, surfynol 440 etc. all available from Air Reduction Chemical Company New York.
• the DTR-process is normally carried out at a temperature in the range of 10°C to 35 ° C.
• a comparitive coating solution (no. 1) containing AgNiS physical development nuclei was prepared as follows.
• Solution A and B are simultaneously added to solution C at a rate of 100ml/min. whilst stirring solution C at 400rpm. After the addition of A and B to C the obtained mixtured was stirred for an additional 5 minutes.
• Coating solutions according to the invention were prepared similar to the above procedure with the exception however that one of the compounds according to formula (I) was added to the obtained nuclei solution before coating. Details about the coating solutions according to the invention are given in table 2. Image receiving materials 1 to 6 were obtained by providing respectively each of the coating solutions 1 to 6 to one side of a paper support having a weight of 110 g/m 2 and being coated at both sides with a polyethylene layer to a dry coverage of 2 g/m 2. A top layer was then provided of 0.7 g of gelatin per m 2 .
• a paper support having a weigth of 110g/m 2 being coated at both sides with a polyethylene layer was coated at one side with an antihalation layer on the basis of carbon black dispersed in gelatin wherein also hydroquinone and 1-phenyl-4-methyl-pyrazolidin-3-on were present in a coverage of 0.57 g/m 2 and 0.32 g/m 2 .
• an orthochromatically sensitized negative working gelatino silver halide emulsion layer containing an amount of silver chlorobromide (1.8 mol % bromide) equivalent to 2.0 g/m 2 of silver nitrate was coated.
• the average grain size of the silver chlorobromide was 0.3 microns.
• the silver halide emulsion layer was overcoated with a thin protective gelatin layer.
• the direct-positive working silver halide emulsion material was prepared analogously to Material C of the Example of US-P 4,144,064. The following processing solutions were prepared.
• the photographic materials were exposed through a sensitometric wedge in a contact exposure apparatus operating with a light source having a colour temperature of 3200 ° K.
• the exposed photographic materials were pre-moistened with the above defined processing liquids, the contact time with said liquid being 6 seconds before being pressed together with an image-receiving material as defined above.
• the transfer processor employed was a COPYPROOF (registered trade name of AGFA-GEVAERT N.V.) type CP 380.
• the transfer contact time was 30 seconds.
• the processing was carried out at different processing liquid temperatures being 16, 22 and 32 ° C respectively.
• test wedge prints of the image-receiving materials were evaluated with regard to maximum density (D max ) and gamma values measured as the maximum gradient between 25% above the minimum density and 25% below the maximum density (G(S)) and between the minimum density and 25% above the minimum density (G(V)), the results of which are listed in the following tables 3 and 4 corresponding to DTR-processes carried out using respectively the negative and positive working light sensitive material.
• the negative material was processed with processing solution P1 and the positive working light sensitive material using processing solution P2.

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• 1992
  • 1992-11-23 EP EP92203597A patent/EP0546599A1/fr not_active Withdrawn
  • 1992-12-07 JP JP35168992A patent/JPH05265163A/ja active Pending

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