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
  • G03C1/00—Photosensitive materials
  • G03C1/76—Photosensitive materials characterised by the base or auxiliary layers
• • 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
  • G03C1/00—Photosensitive materials
  • G03C1/005—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein
  • G03C1/04—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein with macromolecular additives; with layer-forming substances

Definitions

• the present invention relates to a silver halide photographic material, more specifically to a silver halide photographic material with a layer assembly specially suited for rapid processing.
• a critical point in the chemical reduction of silver halide in hydrophilic aqueous surroundings is that the process is diffusion-controlled. Therefore the processing velocity can only be improved by increasing the concentration gradient for reactants involved in the different processing steps.
• An increase of the concentration gradient can in the first place be realised by increasing the concentration of the reactants which action is limited for ecological reasons.
• Another possibility is decreasing the thickness of the photographic material which is only limited by the amount of binder and polymers while these are necessary to make stable dispersions of silver halide grains and if desired of ingredients which have to be coated (in an emulsion-, antistress layer, etc) on the support.
• Another limiting factor in decreasing the layer thickness is often the necessity for storing products in order to realize the desired photographic properties.
• Undercoatlayers are often used for incorporating antihalation dyes (like for instance in EP-A 0 307 867, EP-A 0 307 868, US H1515H and US-P 5,230,994) or for the incorporation of dyes which decrease the cross-over in X-ray materials (like for instance in EP-A 0 401 709). However this is always carried out without paying extra attention to the total layer thickness.
• the present invention will bring a proposal in which the described problem is solved and wherein an increase in processing velocity is realised without loss of photographic quality. This will be explained in the following description and the appending example.
• the photographic material to be used in the present invention comprises a layer assembly which contains at least at one side of a support a number of hydrophilic colloid layers which can be described as:
• hydrophilic colloid layers which contain one or more hydrophilic polymers as binder. While the amount of these polymers has a direct influence on the thickness of the hydrophilic layers and therefore on the thickness of the whole material it is important for the realization of this invention that the amount of polymer is restricted for each layer as follows:
• the amount of hydrophilic polymer is not more than 3 gram per m 2 per side of the support while the amount of silver halide per m 2 should be less than 0.05 mole per side.
• the amount of silver halide is not more than 0.04 mole or more preferably not more than 0.035 mole per m 2 and per side of the support.
• the hydrophilic polymer plays a central role in this invention and can be present in many different ways: alone or mixed with other hydrophilic polymers or mixed up with one or more products which can influence the typical elastomeric properties of the polymers.
• Suitable hydrophilic colloids include in the first place naturally occurring substances like proteins, protein derivatives, cellulose derivatives, gelatine and derivatives and polysaccharides. This class also includes oxidized gelatine which can be formed with a oxidizing agent specially for methionine what can be realized prior to or during emulsion precipitation. Another class of hydrophilic colloids is formed by silica, derivatives and analogue products.
• Hydrophilic colloids which can be used alone or in combination with one of the polymers mentioned before is the group of synthetic hydrophilic polymers like polyvinylalcohol and its derivatives, polyacrylamide, polyacrylate and many others.
• a special category is formed by the latex polymers which are added to achieve specific properties in the preparation stage of the photographic material or in the material itself like for instance viscosity increase, decrease of pressure sensitivity, the improve of dryability, etc.
• An important group of products which influence the matrix of the hydrophilic polymer fundamentally is formed by the hardeners from organic or inorganic ridge which can be used alone or in combination, in free or in masked form. Typical useful hardeners are formaldehyde, free dialdehydes, epoxides and many others. All the possibilities which can be used in this invention including many references are described in Res.Disclosure, (sept. 1996), number 38957, section II.
• the light sensitive emulsion of this invention is a silver halide emulsion which can be prepared in various ways by conventional methods. These always start with a nucleation phase followed by a grain growth phase. In this last phase of the emulsion preparation reactants are added to the reaction vessel in the form of solutions of silver and halide salts or in the form of preformed silverhalide nuclei or fine grains which easily dissolve in the precipitation medium.
• the individual reactants can be added through surface or subsurface delivery tubes by hydrostatic pressure or by an automatic delivery system for maintaining the control of pH and/or pAg in the reaction vessel and of the rate of the reactant solutions introduced in it.
• the reactant solutions or dispersions can be added at a constant rate or a constantly increasing, decreasing or fluctuating rate, if desired in combination with stepwise delivery procedures. More details about the possible ways in making a silver halide emulsion which can principally be used in this invention are summarized in Res.Disclosure, (sept. 1996), number 38957, section I-C.
• additional metal salts or complexes can be added for occlusion in the crystal lattice.
• Such compound is replacing an appropiate amount of silver and halide ions in the silver halide lattice.
• dopants can be distinguished from the metal complexes which are added just before coating as an additive by EPR- or ENDOR-technique. These dopants can be used to modify the crystal structure or the crystal properties and can therefore be employed to influence many photographical properties like sensitivity, reciprocity failure, gradation, pressure sensitivity, fog, stability, etc..
• Dopants which are introduced in emulsions of the present invention are those which can act as a permanent or as a non-permanent electron trap.
• the doping procedure itself can normally be executed at any stage during the grain growth phase of the emulsion preparation. It is important to know that the dopants can also be added in an indirect way by the addition of a dispersion containing very fine soluble silver halide grains or nuclei comprising the dopant. More additional information about the introduction and the use of dopants in the emulsion crystals of this invention can be found in Res.Disclosure, (sept. 1996), number 38957, section I-D.
• the photographic emulsions prepared in this way contain silver halide crystals comprising chloride, bromide or iodide alone or combinations thereof. It is a preferred embodiment of this invention that the silver halide grains contain chloride if desired next to other halides. Additionally it is also possible to incorporate other silver salts like silver phosphate, silver thiocyanate, silver citrate and some other silver salts in a limited amount in the silver halide lattice. The chloride and bromide halide can be combined in all ratios to form a silverchlorobromide salt.
• Iodide ions however can be coprecipitated with chloride and/or bromide ions thus forming a iodohalide with an iodide amount which depends on the saturation limit of iodide in the lattice with the given halide composition; this means up to a maximum amount of about 40 mole percent in silver iodobromide and up to at most 13 molevig in silver iodochloride both based on silver.
• the composition of the halide can change in the crystal in a continuous or discontinuous way.
• Emulsions containing crystals composed of various sections with different halide compositions are used for several photographic applications.
• Such a structure with a difference in halide composition between the center and the rest of the crystal what is called 'core-shell'-emulsion) or with more than two crystal parts differing in halide composition (called a 'band'-emulsion) may occur.
• the changes in halide composition can be realised by direct precipitation or in an indirect way by conversion where fine silver halide grains of a certain halide composition are dissolved in the presence of the so-called host grains forming a 'shell' or 'band' on the given grain.
• the crystals formed by the methods described above have a morphology which can be tabular or non-tabular.
• the aspect ratio ratio of equivalent circular diameter to thickness
• the major faces of the formed tabular grains can have a ⁇ 111 ⁇ or a ⁇ 100 ⁇ -habitus which structure is stable or should be stabilised for instance by a 'habitus modifying agent'.
• the class of non-tabular grains there are a lot of possibilities which can be divided in the more regular shaped crystals or the crystals with a mixed crystal habit.
• the emulsions can be coagulated and washed after precipitation in order to remove the excess soluble salts.
• These procedures which can be used in this invention are together with different alternative methods like dia- or ultrafiltration and ion-exchange described in Res.Disclosure, (sept. 1996), number 38957, section III.
• Additional gelatin or another hydrophilic colloid, suitable as a binder material can be added at a later stage of the emulsion preparation e.g. after washing, in order to establish optimal coating conditions and/or to establish the required thickness of the coated emulsion layer.
• a gelatin to silver halide ratio silver halide being expressed as the equivalent amount of silver nitrate, ranging from 0.08 to 1.0 is then obtained.
• Another binder may also be added instead of or in addition to gelatin.
• Useful vehicles, vehicle extenders, vehicle-like addenda and vehicle related addenda have been described e.g. in Res.Disclosure, (sept. 1996), number 38957, Chapter II.
• the emulsions can be surface-sensitive emulsions which form latent images primarily on the surface of the silver halide grains or they can be emulsions forming their latent-image primarily in the interior of the silver halide grain.
• the emulsions can further be negative-working emulsions such as surface sensitive emulsions or unfogged internal latent image-forming emulsions.
• direct-positive emulsions of the unfogged, latent image-forming type which are positive-working by development in the presence of a nucleating agent, and even pre-fogged direct-positive emulsions can be used in the present invention.
• the silver halide emulsions can be surface-sensitized by chemical sensitization which can be done in many different ways, in presence of a chalcogen as sulfur, selenium or tellurium, in presence of a noble metal as for instance gold or in combination with a chalcogen and noble metal.
• the chemical sensitization can also be done by reduction sensitization if desired combined with the chalcogen/noble metal-sensitization.
• a reducing compound is used like thiourea dioxide, hydrazine derivatives, sulphinic acid, polyamine compounds, stannous chloride, borane compounds, reductones like ascorbic acid, etc.
• Reduction sensitization can also be carried out at a low pAg or a high pH or at both and if desired at elevated temperature.
• This kind of sensitization is refered to 'silver ripening'. More information can be found in Res.Disclosure, Vol. 307, number 307105 and in P.Glafkides "Chimie et Physique Photographic", P.Montel - Paris, 5 th Ed.,1987. The presence of certain 'modifying' agents as for instance spectral sensitizers which can optimize the chemical sensitization process are often used. A complete description of all the different possibilities with respect to this subject can be found in Res.Disclosure, (sept.1996), number 38957, section IV.
• the silver halide emulsions are spectrally sensitized with dyes from different classes which include polymethine dyes comprising cyanines, merocyanines, tri-, tetra- and polynuclear cyanines and merocyanines, oxanols, hemioxanols, styryls, merostyryls and so on.
• dyes from different classes which include polymethine dyes comprising cyanines, merocyanines, tri-, tetra- and polynuclear cyanines and merocyanines, oxanols, hemioxanols, styryls, merostyryls and so on.
• more than one spectral sensitizer may be used in the case that a larger part of the spectrum has to be covered.
• the photographic elements comprising the said silver halide emulsions can include various compounds which should play a certain role in the material itself or afterwards in the processing, finishing or warehousing the photographic material.
• These products can be stabilizers and anti-foggants (see Res.Disclosure, (sept. 1996), number 38957, section VII), brighteners (see Res.Disclosure, (sept. 1996), number 38957, section VI), light absorbers and scattering materials (see Res.Disclosure, (sept. 1996), number 38957, section VIII), coating aids (see Res.Disclosure, (sept. 1996), number 38957, section IXA), antistatic agents (see Res.Disclosure, (sept.
• the photographic elements can be coated on a variety of supports as described in Res.Disclosure, (sept. 1996), number 38957, section XV and the references cited therein.
• the photographic elements can be exposed to actinic radiation, specially in the ultra-violet, visible, near-ultraviolet and near-infrared region of the spectrum, to form a latent image (see Res.Disclosure, (sept. 1996), number 38957, section XVI).
• This latent-image can be processed in order to form a visible image (see Res.Disclosure, (sept. 1996), number 38957, section XIX).
• the preparation procedure was started with adding 1.5 ml of an 3.54*10 -4 molar solution of Na 3 RhCl 6 .12H 2 O and 1.0 ml of an 1.79*10 -3 molar solution of Na 2 IrCl 6 .6H 2 O to solution (2) immediately followed by the addition of 0.5 ml of a 0.3 molar AgNO 3 -solution during 180 sec to the reaction vessel containing 46 grams of inert gelatine in 1 liter demineralized water at 50 °C. After adjusting the pH on 3.0 and the pAg on 7.04 in the reaction vessel the nucleation was started by adding 15.8 ml per min.
• the emulsion was further flocculated by adding 55 ml of a 15 weight % solution of polystyrene sulphonic acid and after ca 20 minutes sedimentation the mother liquid was removed, demineralized water added and the remaining salts were washed out by repeating this procedure.
• the silver halide emulsion prepaired in this way contained crystals which had a mean spherical diameter of 0.20 ⁇ m.
• the temperature was lowered till 38 °C while the pH was adjusted at 5.0 immediately followed by the subsequent addition of an amount of triazaindolizine sufficent to stabilize the emulsions and by several wetting agents in order to coat the emulsions on a terephtalate support.
• the amount of silver halide was in all the coatings 6 g/m 2 .
• the hardening was realized by the addition of 0.5 ml of a 2 weight % solution of divinylsulphonylmethane per gram of gelatine.
• the resulting composition of the different coated materials are summarized in Table 1.
• the thickness is always expressed as the amount of hydrophilic polymer (in grams per m 2 ).
• the processing was carried out by using a G101c (trademark of GEVAERT), a hydrochinon-phenidon developer which was diluted with 2 parts of demineralized water on 1 part G101c, followed by a G333-fixer (trademark GEVAERT) which was diluted with 4 parts of demineralized water in one part of G333, both at a temperature of Composition of the layer assembly Ref. Nr.
• A/B B/C Polymer amount layer A (g/m 2 ) Polymer amount layer B (g/m 2 ) Polymer amount layer C (g/m 2 ) Total Polymer amount (g/m 2 ) Note 1 0 2.1 0 2.3 1.1 3.4 ref 2 0 0.8 0 1.3 1.6 2.9 inv 3 0.23 1.0 0.3 1.3 2.9 inv 4 0.46 1.3 0.6 1.3 1.0 2.9 inv 5 0.76 2.2 1.0 1.3 0.6 2.9 inv 35 °C and each time during 15 sec. After washing and drying the density which was realized after processing as a function of the light dose was measured and used to determine the following parameters:

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Citations (6)

• 1998
  • 1998-09-28 EP EP98203261A patent/EP0911694A1/fr not_active Withdrawn
  • 1998-10-19 JP JP29595498A patent/JPH11194453A/ja active Pending

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