WO2004057420A1 - High bromide {111} tabular grain emulsions with improved dispersity - Google Patents
High bromide {111} tabular grain emulsions with improved dispersity Download PDFInfo
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- WO2004057420A1 WO2004057420A1 PCT/NL2003/000914 NL0300914W WO2004057420A1 WO 2004057420 A1 WO2004057420 A1 WO 2004057420A1 NL 0300914 W NL0300914 W NL 0300914W WO 2004057420 A1 WO2004057420 A1 WO 2004057420A1
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- silver halide
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- 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
- G03C1/0051—Tabular grain emulsions
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- 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
- G03C1/047—Proteins, e.g. gelatine derivatives; Hydrolysis or extraction products of proteins
Definitions
- the invention relates to ⁇ 111 ⁇ tabular silver halide emulsions that are useful in the field of photography and particularly to a process for preparing the ⁇ 111 ⁇ tabular silver halide emulsions.
- ⁇ 111 ⁇ tabular silver halide grains having parallel twin planes have the following photographic properties:
- the amount of silver coated can be smaller than in the case of using a non- ⁇ 111 ⁇ tabular grain emulsion, and the sensitivity/graininess ratio is therefore high.
- the ⁇ 111 ⁇ tabular grains have hitherto been used in many commercially produced photographic materials.
- a high aspect ratio is an important feature of tabular grains to demonstrate their advantages fully.
- tabular grains having a high aspect ratio have a broad distribution of the diameter of the projected area. This is an important drawback of the existing tabular grain technology.
- the ⁇ 111 ⁇ tabular grains are disadvantageous in the following respects:
- a multi-layered structure which has an upper layer formed of monodisperse large grains and a lower layer formed of monodisperse small grains utilizes light more efficiently and hence has higher sensitivity than a single layered structure which has an emulsion coating layer which contains large grains and small grains together. In case of heterodisperse ⁇ 111 ⁇ tabular grain emulsions this advantage of an allocation of the different grain sizes to separated layers cannot be utilized well.
- ⁇ 111 ⁇ tabular grains are formed in three subsequent processes, i.e., the nucleation, the ripening, and the grain growth process.
- the next ripening process is designed in such a way that all non-tabular grains are dissolved without reducing the total number of tabular grains, and finally the grain growth process has the function to increase the sizes of tabular grains to their finally desired sizes.
- cubic crystals have a mechanism of growth that is completely different from ⁇ 111 ⁇ tabular crystals, and that experimental data on the effect of hydrolysed gelatins on the homodispersity of cubic crystal populations are not relevant for their use in ⁇ 111 ⁇ tabular crystal grain formation processes.
- Cubic crystals are bounded by ⁇ 100 ⁇ faces where as the large top and bottom surfaces of tabular crystals consists of ⁇ 111 ⁇ surfaces.
- a further object of this invention is to provide a ⁇ 111 ⁇ tabular silver halide emulsion with an excellent grain size distribution without introducing additional process steps.
- Another object of the invention is to provide a silver halide emulsion with thin ⁇ 111 ⁇ tabular crystals with a high aspect ratio having excellent sensitivity and graininess.
- a preferred adsorption to ⁇ 111 ⁇ surfaces of polymers added in the tabular grain formation process was of influence on the grain size distribution. More precisely, it was found that the objects of the invention could be reached by a process in which polymers with a preferred adsorption to ⁇ 111 ⁇ surfaces over ⁇ 100 ⁇ surfaces was added.
- the tabular grain formation process comprises the steps of nucleation and ripening. Most precise the water-soluble polymeric compound is added during the nucleation step. In one embodiment preferably the pH during the nucleation step is less than 6. In a further embodiment preferably the pH during the nucleation step is 6 or higher. Preferably the pH of the nucleation step is maintained during the ripening step.
- the invention relates to a ⁇ 111 ⁇ tabular silver halide emulsion produced in said process, having an improved homodispersity that is expressed as RDA, the ratio between the distribution width at half peak height in nanometers and the average aspect ratio.
- the invention relates to a ⁇ 111 ⁇ tabular silver halide emulsion wherein at least 60% of the total projected grain area of said silver halide grains are ⁇ 111 ⁇ tabular silver halide grains with a silver bromide content of at least 50% obtainable with the method according to the invention. Also the invention relates to photographic material comprising on a support at least one layer comprising a ⁇ 111 ⁇ tabular silver halide emulsion according to the invention.
- the invention is directed to ⁇ 111 ⁇ tabular high bromide silver halide emulsions wherein at least 60% of the total projected grain area of said silver halide grains are ⁇ 111 ⁇ tabular silver halide grains with an average aspect ratio of 6 to 40 and a thickness of less than 0.2 micron with improved homodispersity.
- tabular grains indicates grains having two parallel grain faces which are clearly larger than any remaining grain face.
- Tabular grain emulsions are emulsions in which tabular grains account for more than 50% of the total grain projected area.
- the aspect ratio is a value obtained by dividing the diameter of the largest surface area of the individual tabular grain by the thickness thereof.
- the word "diameter,” used here, means the diameter of a circle that has an area equal to the projected area of the grain, which is determined through microscope or electron microscope observation. Hence, an aspect ratio of 8 or more means that the diameter of that circle is 8 or more times greater than the thickness of the grain.
- the average aspect ratio is high, the polydispersity becomes also higher and gradation of the silver halide emulsion becomes soft. In addition, pressure marks will occur. On the other hand, if the average aspect ratio is too low, the excellent properties in terms of sensitivity of the tabular grain emulsion will be diminished.
- An example of methods of measuring the aspect ratio is the replica method in which the equivalent-circle diameter (ECD) and thickness of each grain are detected from the photograph of that grain which has been taken by a transmission elecfron microscope.
- ECD equivalent-circle diameter
- the thickness is calculated from the length of the shadow of a replica.
- the variation coefficient of grain size can be expressed as a value obtained by dividing the standard deviation of the equivalent-circle diameters of projected areas of all silver halide grains, by the average diameter of the silver halide grains.
- RDA homodispersity
- the tabular grains having high aspect ratios can be formed using various methods. For instance, the grain fomiation methods disclosed in U. S. Pat. Nos. 5,496,694 and 5,498,516 can be adopted in the invention. Further, the tabular grains having ultrahigh aspect ratios can be formed using the grain formation methods disclosed in U.S. Pat.
- the addition of a polymer with a preferred adsorption to the ⁇ 111 ⁇ surfaces of the silver halide grains increases the homodispersity.
- the invention comprises nucleation in the presence of a gelatin-like polymer having a molecular weight of less than 50 kilo Dalton, most preferably from 3 to 25 kilo Dalton.
- the water-soluble polymeric compound is added simultaneously with the silver salt and the halide salt in the nucleation step instead of adding silver- and halide salt in a dispersion medium in which the polymeric compound is already present.
- This can be performed in particularly by mixing the polymeric compound with the aqueous solution of halide salt used for nucleation. This is mixed with the aqueous solution of a silver salt in a nucleation chamber, which is located in a larger vessel.
- nucleation peptizer preferably at most 80% of the nucleation peptizer is the special gelatin having the preferred ⁇ 111 ⁇ adso ⁇ tion as defined above, the remaining at least 20% of the nucleation peptizer consisting of conventional gelatins.
- the polymeric compound is a polypeptide
- it preferably comprises an amino acid selected from arginine, lysine, hydroxylysine and histidine as the carboxy-terminal amino acid.
- the nucleation step and preferably ripening step are preferably carried out at a pH of 6 or higher, more preferably at a pH higher than 7, most preferably at a pH between about 8 and 11.
- a pH higher than 11 can be applied but is less preferred because hydrolysis of the polypeptide may occur.
- polypeptides of this invention are not limited to structures with a C-terminal amino acid that contain a free amine group (like histidine, arginine or lysine).
- a terminal C- or N- side of the polypeptide may also comprise two amino acids within each other's vicinity, one amino acid 'A' having a restgroup containing an amine group and one amino acid 'B' having a restgroup containing a carboxyl group. These amino acids should preferably not be separated by more than 5 amino acids, preferably by at most 4 amino acids, more preferably by at most 2 amino acids most preferably by at most 1 amino acid.
- the terminal sides of the polypeptide can also contain more than one amino acid 'A' and/or 'B'.
- Such structures can be, for example:
- the nucleation step is carried out at a pH of 7 or more, preferably at a pH of at least 8, more preferably at a pH between about 8 and 11 in the presence of a polypeptide in which amino acid 'A' is arginine or lysine.
- the compound is present in the nucleation step in an amount of about 0.01 to 0.2 mol per mol silver, preferably 0.05 to 0.1 mol per mol silver.
- Preferred low molecular weight gelatin-like polymers for use in the method of the invention can be prepared by subjecting a natural gelatin or modified natural gelatin - like oxidised, phthalated, trimellitated, pyromelhtated gelatin - to hydrolysis by specific enzymes like trypsin, which cuts the gelatin next to a lysine or arginine amino acid in the polypeptide chain.
- specific enzymes like trypsin, which cuts the gelatin next to a lysine or arginine amino acid in the polypeptide chain.
- Other specific enzymes may be selected from the group comprising acrosin and tryptase and lysyl and endopeptidase and Venobin AB and trypsin and peptidyl-lys metalloendopeptidase.
- Low molecular weight gelatin-like polymers can also be prepared synthetically or with recombinant techniques as described in EP 1,014,176, US 5,773,249 and US 5,496,712
- the preferred adso ⁇ tion to ⁇ 111 ⁇ faces can be expressed in an adso ⁇ tion parameter, which parameter is calculated by the method explained in detail in example 1.
- the preferred adso ⁇ tion of the inventive gelatin-like compound is in terms of this parameter lower than -3, more preferably lower than —4 and most preferably lower than -6.
- additional amino acids or poly-amino acids comprising Histidine, Lysine, Hydroxylysine or Arginine can be chemically cross-linked to a polypeptide.
- Methods are described in The Practice of Peptide synthesis, M. Bodansky, A. Bodansky, Springer- Verlag, Berlin 1984 and Solid Phase Peptide synthesis, J.M. Steward, J.D. Young, San Francisco, W.H. Freeman and Company, 1989).
- An additional amino acid that is thus linked to the amine of an amino acid present in a gelatin-like polypeptide could have itself two primary amines available for further cross-linking of (poly)amino acids.
- Such a structure which provides additional sites for cross-linking is called a spacer and can in this case be any molecule that has a functional group which can be linked to a primary amine of a gelatin-like polymer and has itself at least two free primary amines.
- a spacer is dendrites
- a gelatin having an Arginine or Lysine at the amino-terminal position may be chemically modified in such a way that a free carboxyl groups is infroduced in the amino terminal region.
- the nuclei of non-twinned crystals, singly twinned crystals and non-parallel multiply twinned crystals will dissolve by physical ripening in the ripening process step, and only the nuclei of parallel multiply twinned crystals will not dissolve.
- supplementary gelatin is added, and then a soluble silver salt and soluble halide(s) are added, thereby performing the grain growth.
- supplementary gelatin normal gelatins or gelatins whose amino groups are modified with for example phthalic acid, trimellitic acid or pyromellitic acid can be used.
- silver and halide(s) are supplied by the addition of fine grains of silver halide prepared in advance separately or those prepared in a separate reaction vessel at the same time.
- any of silver bromide, silver chlorobromide, silver iodobromide, silver iodochloride, silver chloride and silver chloroiodobromide can be used in the invention.
- the use of silver iodobromide or silver chloroiodobromide is preferable.
- the emulsion grains have faces containing iodide or chloride, these faces may be uniformly distributed inside the grains, or non- uniformly distributed.
- Other silver salts such as silver thiocyanate, silver sulfide, silver selenide, silver carbonate, silver phosphate and silver salts of organic acids, maybe present as separate grains, or as a component of silver halide grains.
- the bromide content in the emulsion grains is at least 80 mole %, preferably at least 90 mole %, of the total amount of halide.
- the suitable iodide content in the present emulsion grains is from 1 to 20 mole %, preferably from 2 to 15 mole %, more preferably from 3 to 10 mole % of the total amount of halide.
- An iodide content lower than 1 mole % is undesirable, because this makes it difficult for the grains to have the effects of intensifying the dye adso ⁇ tion and increasing the intrinsic sensitivity.
- the iodide contents higher than 20 mole % are also undesirable, because they generally cause a decrease in development speed.
- the ⁇ 111 ⁇ tabular silver halide crystals may be host crystals with epitaxially grown guest crystals as described in US 6,337,177. It is desirable that the present silver halide tabular grains have at least one kind of a photographically useful metal ion or complex (hereinafter referred to as "metal (complex) ion”) in their respective insides.
- metal (complex) ion a photographically useful metal ion or complex
- photographically useful metal (complex) ions means the dopants added to silver halide grains for the pu ⁇ ose of improving the photographic characteristics of a photosensitive silver halide emulsion.
- the metal (complex) ions added as dopants function as transitional or permanent traps for electrons or positive holes in the silver halide crystals to produce beneficial effects, such as enhancement of sensitivity and contrast, improvement in reciprocity characteristics and improvement in resistance to damage by pressure.
- metal ions used for doping the present emulsion grains include the ions of the first to third transition metals, such as iron, ruthenium, rhodium, palladium, cadmium, rhenium, osmium, iridium, platinum, chromium and vanadium, and the ions of amphoteric metals, such as gallium, indium, thallium and lead.
- these metal ions are used in the form of complex salt or single salt.
- complex ions six-coordinate halogeno- complexes and cyano-complexes having halide ions and cyanide ions as ligands are used to advantage.
- the complexes having organic ligands such as nitrosyl (NO), thionitrosyl (NS), carbonyl (CO), thiocarbonyl (CS), isocyanato (NCO), thiocyanato (SCN), selenocyanato (SeCN), tellurocyanato (TeCN), dinitrogen (N 2 ), azido (N3), bipyridyl, cyclopentadienyl, 1,2- dithiolenyl and imidazolyl ligands, can also be used.
- organic ligands such as nitrosyl (NO), thionitrosyl (NS), carbonyl (CO), thiocarbonyl (CS), isocyanato (NCO), thiocyanato (SCN), selenocyanato (SeCN), tellurocyanato (TeCN), dinitrogen (N 2 ), azido (N3), bipyridyl, cyclopentadie
- ligands usable for the complexes as dopants include multidentate ligands, such as bidentate ligands (e.g., bipyridyl), tridentate ligands (e.g., diethylenetriamine), tetradentate ligands (e.g., triethylenetetramine) and hexadentate ligands (e.g., ethylenediaminetefraacetato).
- the coordination number is preferably 6, but it may be 4.
- the organic ligands disclosed in U.S. Pat. Nos. 5,457,021, 5,360,712 and 5, 462,849 can also be used to advantage.
- metal (complex) ions In inco ⁇ orating metal (complex) ions into silver halide grains, it is important that the size of metal (complex) ion can be inco ⁇ orated into the lattice of silver halide grains. Further, it is essential to doping silver halide grains that the compounds produced from metal (complex) ions and silver or halide ions are co-precipitated with silver halide.
- the pKsp (the common logarithm of the reciprocal of the solubility product) of the compound constituted of a metal (complex) ion and silver or halide ion be on the same level as the pKsp of silver halide (silver chloride 9.8, silver bromide 12.3, silver iodide 16.1). Therefore, it is desirable that the pKsp of the compound constituted of a metal (complex) ion and silver or halide ion is from 8 to 20.
- the amount of the above-recited metal complex used for doping silver halide grains is generally from 10 "9 to 10 "2 mole per mole of silver halide.
- the metal complexes providing transitional shallow electron traps in the sensitizing step be used in the range of 10 to 10 " mole per mole of silver halide; while the metal complexes providing deep electron fraps in the sensitizing step be used in the range of 10 "9 to 10 "5 mole per mole of silver halide.
- the content of metal (complex) ions in emulsion grains can be confirmed by the atomic abso ⁇ tion spectral analysis, the polarized Zeeman spectroscopic analysis or ICP analysis.
- the ligands in a metal complex ion can be confirmed by Infrared abso ⁇ tion (especially FT-IR).
- the metal (complex) ions as dopant may be inco ⁇ orated in the surface or inner core of silver halide grains, or in a very shallow surface shell (the so-called subsurface) having a depth reduced to such an extent as not to expose metal ions as disclosed in U.S. Pat. Nos. 5,132,203 and 4,997,751.
- the location of a dopant may be chosen depending on the intended pu ⁇ ose.
- Two or more kinds of metal ions may be used as dopants, and they may be located at the same shell or separate shells.
- the addition of those compounds may be carried out by previously mixing the metal salt solution with either an aqueous halide solution or an aqueous silver salt solution used for grain formation, or by direct addition of the metal salt solution to the grain formation system. Further, the metal ion-doped fine silver halide emulsion grains may be added.
- an aqueous solution of hydrogen halide e.g., HCl, HBr
- thiocyanic acid or salts thereof e.g., KC1, NaCl, KBr, NaBr
- alkali halide e.g., KC1, NaCl, KBr, NaBr
- the doping of emulsion grains with metal ions of cyano-complexes sometimes generates cyan by the reaction between gelatin and the cyano- complexes to inhibit the gold sensitization.
- the methods of preparing tlie present silver halide emulsions mentioned above and other silver halide emulsions usable together therewith are illustrated below.
- the silver halide grains used in the invention can be prepared basically in accordance with known methods, namely the methods described in, e.g., P. Glafkides, Chimie et Physique Photographique , Paul Montel (1967), G. F. Dufin, Photographic Emulsion Chemistry , The Focal Press (1966), V. L. Zelikman, et al., Making and Coating Photographic Emulsion , The Focal Press (1964). More specifically, the emulsions can be prepared in various pH regions, e.g., using an acid, neutral or ammoniacal process.
- any of a single jet method, a double jet method and a combination thereof can be employed.
- the so-called controlled double jet method wherein the addition of reactant solutions is controlled so as to maintain the pAg value at the intended value during the reaction, can be employed to advantage.
- the method of keeping the pH value constant during the reaction may be employed as well.
- the preparation of the silver halide grains used in the invention is generally effected by feeding a solution of water-soluble silver salt, such as silver nitrate, and a solution of water-soluble halide, such as alkali halide, into an aqueous solution of water-soluble binder, such as gelatin, under the controlled conditions.
- the binder is a polymer with a preferred adso ⁇ tion to the ⁇ 111 ⁇ face.
- the excess water-soluble salts can be removed using the noodle washing method which comprises gelling the gelatin solution containing silver halide grains, cutting into strips and washing out the water-soluble salts with cold water, or the flocculation method in which a flocculant, such as an inorganic salt containing a polyvalent anion (e. g., sodium sulphate), an anionic surfactant, an anionic polymer (e.g., sodium polystyrene suffocate) or a gelatin derivative (e.g., an aliphatic acylated gelatin, an aromatic acylated gelatin, an aromatic carbamoylated gelatin), is added to cause the aggregation of gelatin, thereby removing the excess salts.
- a flocculant such as an inorganic salt containing a polyvalent anion (e. g., sodium sulphate), an anionic surfactant, an anionic polymer (e.g., sodium polystyrene suff
- the silver halide emulsions used in the invention be chemical sensitized using known sensitization methods alone or in various combinations.
- the chemical sensitization contributes to conferring high sensitivity, exposure condition stability and storage stability upon the silver halide grains prepared.
- the chemical sensitization methods used to advantage are a chalcogen sensitization method using a sulphur, selenium or tellurium compound.
- Examples of a sensitizer usable herein include compounds capable of releasing a chalcogen element as recited above to form silver chalcogenide when added to a silver halide emulsion. The combined use of such sensitizers is desirable from the viewpoint of increasing the sensitivity and suppressing the fog.
- the precious metal sensitization method using gold, platinum, iridium or the like.
- the gold sensitization method using chloroauric acid alone or in combination with ions capable of coordinating to gold, such as thiocyanate ion is advantageous because of its high sensitizing effect. Further high sensitivity can be obtained by the combined use of gold sensitization and chalcogen sensitization.
- Another sensitization method used to advantage is the so-called reduction sensitization method wherein reduced silver nuclei are introduced by the use of a compound having moderate reducing power during the grain fo ⁇ nation, thereby increasing the sensitivity. Further, the reduction sensitization method of adding an aromatic ring-containing alkinylamine compound at the time of chemical sensitization is favourably used.
- the pH is from 5.0 to 11.0, preferably from 5.5 to 8.5; and the pAg is from 6.0 to 10.5, preferably from 6.5 to 9.8.
- the arts of chemical sensitization are described in, e.g., JP-A-3-110555, JP-A-5-241267, JP-A- 62- 253159, JP-A-5-45833 and JP-A-62-40446.
- the light-sensitive silver halide emulsions used in the invention are desirably subjected to the so-called spectral sensitization to acquire sensitivities in the desired wavelength regions.
- photosensitive layers having sensitivities to blue, green and red lights respectively are inco ⁇ orated in a color photographic material for the pu ⁇ ose of reproducing colors faithful to an original.
- These color sensitivities are conferred by spectrally sensitizing silver halide with the so-called spectral sensitizing dyes.
- Such sensitizing dyes include cyanine dyes, merocyanine dyes, complex cyanine dyes, complex merocyanine dyes, holopolar dyes, hemicyanine dyes, styryl dyes and hemioxonol dyes. Examples of these dyes are disclosed in U.S. Pat. No. 4,617,257, JP- A-59- 180550, JP-A-64- 13546, JP-A-5-45828, JP-A-5-45834 and soon. Those spectral sensitizing dyes are used alone or as a combination of two or more thereof.
- the combination of dyes is employed for the pu ⁇ ose of controlling the wavelength distribution of spectral sensitivity or obtaining supersensitizing effect.
- the supersensitizing combination of dyes can achieve the sensitivity materially greater than the sum of the sensitivities achieved by individual dyes.
- Such supersensitizing compounds include diaminostilbene compounds. Examples thereof are disclosed in U.S. Pat. No. 3,615,641, JP-A-63-23145 and so on.
- spectral sensitizing dyes and supersensitizing compounds may be added to silver halide emulsions at any stage of emulsion-making. Specifically, they may be added to a chemically sensitized emulsion at the time of preparing a coating solution using the emulsion, or their addition to an emulsion may be at the conclusion of, during or prior to chemical sensitization, or they may be added within a period from the completion of grain formation to the start of desalting, during the grain formation or prior to the grain formation. These ways of addition may be adopted independently or as combination of two or more thereof. For achievement of high sensitivity, the addition in steps prior to chemical sensitization is effective.
- the spectral sensitizing dyes and supersensitizing compounds each can be added in an amount chosen from a wide range depending on the shape and size of emulsion grains and the photographic characteristics intended to be conferred thereby. In general, however, the addition amount ranges from 10 "8 to 10 _1 mole, preferably from 10 "5 to 10 " mole, per mole of silver halide. Those compounds are dissolved in an organic solvent, such as methanol or fluorinated alcohol, or dispersed into water together with a surfactant and gelatin, and then added to silver halide emulsions.
- an organic solvent such as methanol or fluorinated alcohol
- the silver halide emulsions used in the invention can contain a wide variety of stabilizers for pu ⁇ oses of preventing fogging or heightening stability during storage.
- Suitable examples of a stabilizer include nitrogen-containing heterocyclic compounds such as azaindenes, triazoles, tetrazoles and purines, and mercapto compounds such as mercaptotetrazoles, mercaptotriazoles, mercaptoimidazoles and mercaptothiadiazoles. The details of these compounds are described in T. H. James, The Theory of the Photographic Process , pages 396-399, Macmillan (1977) and the references cited therein.
- antifoggants the mercaptoazoles having an alkyl group containing at least 4 carbon atoms and two or more aromatic groups as substituents are preferably used in the invention.
- antifoggants or stabilizers may be added to silver halide emulsions at any stage of emulsion-making. Specifically, they may be added within a period from the conclusion of chemical sensitization to the start of preparing a coating solution, at the conclusion of, during or prior to chemical sensitization, within a period from the completion of grain formation to the start of desalting, during the grain formation, or prior to the grain formation. These ways of addition may be adopted independently or as combination of two or more thereof.
- antifoggants or stabilizers can be added in an amount chosen from a wide range depending on the halide composition of emulsion grains and the required pu ⁇ ose. In general, however, the addition amount ranges from 10 "6 to 10 _1 mole, preferably from 10 "5 to 10 "2 mole, per mole of silver halide.
- the aforementioned photographic additives which are usable in the invention, are described in US 6,337,177 column 15-16.
- the tabular crystals may be host crystals with epitaxially grown guest crystals as described in US 6,337,177
- the present ⁇ 111 ⁇ tabular grains have at least two parallel twinning planes per grain and have a triangular or hexagonal shape the corners of which may be sha ⁇ or round. When they have a hexagonal shape, each pair of sides facing each other have outer surfaces parallel to each other.
- the twinning plane distance in the present ⁇ 111 ⁇ tabular grains may be determined depending on the intended pu ⁇ ose. For instance, it may be controlled to at most 0.012 micron as disclosed in U.S. Pat. No. 5,219, 720, or the ratio of the distance between (111) major planes to the twinning plane interval may be controlled to at least 0.015 micron as disclosed in JP-A-5-249585.
- the ⁇ 111 ⁇ tabular grains account for 100 to 80%, preferably 100 to 90%, particularly preferably 100 to 95%, of all the grains in the emulsion on a projected area basis.
- the advantages of ⁇ 111 ⁇ tabular grains cannot be used to the full.
- the hexagonal ⁇ 111 ⁇ tabular grains having a ratio of adjacent sides (a longest side/shortest side ratio) in the range of 1.5 to 1 account for 100 to 50%, preferably 100 to 70%, particularly preferably 100 to 80%, of all the grains in the emulsion on a projected area basis. It is more desirable that the hexagonal ⁇ 111 ⁇ tabular grains having a ratio of adjacent sides in the range of 1.2 to 1 account for 100 to 50%, preferably 100 to 70%o, particularly preferably 100 to 80%, of all the grains in the emulsion on a projected area basis. Mixing with ⁇ 111 ⁇ tabular grains other than the hexagonal ones is undesirable because the uniformity is lacking in the grains.
- the average grain thickness of the ⁇ 111 ⁇ tabular crystals is from 0.05 to 0.2 micron, preferably from 0.05 to 0.15 micron.
- the term average grain thickness as used herein refers to the arithmetic mean of grain thickness values of the total ⁇ 111 ⁇ tabular grains in the emulsion. It is difficult to prepare the emulsion grains having an average grain thickness thinner than 0.05 micron. The emulsion grains having an average grain thickness thicker than 0.2 micron are undesirable.
- the suitable average projected area diameter of the present ⁇ 111 ⁇ tabular grains is from 0.8 to 4 micron, preferably from 1 to 3.5 micron, particularly preferably from 1.2 to 3 micron.
- the term "average projected area diameter" used herein refers to the arithmetic mean of the projected area diameter values of the total ⁇ 111 ⁇ tabular grains in the emulsion.
- the average projected area diameter smaller than 0.8 micron is undesirable because of difficulty in achieving the present effects.
- the average projected area diameter greater than 4 micron is also undesirable, because it causes deterioration in the resistance to damage by pressure.
- the projected area diameter/thickness ratio of each silver halide grain is referred to as the aspect ratio. More specifically, the aspect ratio is a value obtained by dividing the diameter of a circle having the same area as the projected area of each silver halide grain by the grain thickness.
- the replica method in which the transmission elecfron photomicrographs of silver halide grains are taken and thereby the diameter of a circle having the same area as the projected area of each grain (projected area diameter) and the thickness of each grain are determined. In this method, the thickness is calculated from the length of the replica shadow.
- the ⁇ 111 ⁇ tabular grains having an average aspect ratio of 4 to 50 comprise 100 to 80% of the total silver halide grains in the emulsion on a projected area basis.
- the ⁇ 111 ⁇ tabular grains having an average aspect ratio of 6 to 50 comprise 100 to 80% of the total silver halide grains in the emulsion on a projected area basis.
- the ⁇ 111 ⁇ tabular grains having an average aspect ratio of 8 to 50 comprise 100 to 80% of the total silver halide grains in the emulsion on a projected area basis.
- the suitable average aspect ratio for the total ⁇ 111 ⁇ tabular silver halide grains in the present emulsion is from 4 to 40, preferably from 6 to 40, more preferably from 12 to 35.
- the term average aspect ratio refers to the arithmetic mean of the aspect ratio values of total ⁇ 111 ⁇ tabular grains in the emulsion.
- the average grain thickness, the average aspect ratio and the homodisperse degree can be selected from their respective ranges mentioned above depending on the intended pu ⁇ oses, it is advantageous to the invention to use homodisperse ⁇ 111 ⁇ tabular grains having a small thickness and a high aspect ratio.
- the preferred crystal faces to which a polymeric compound adsorbs is detennined by a quantitative determination of the adso ⁇ tion of the polymeric compound on cubic and on octahedral crystal faces using a Kubelka-Munk method as for example described by T.Tani, J.Imag.Sc, 1985, vol 29, 165.
- the emulsions used are a cubic silver bromide emulsion with an average grain size of
- the gelatin present in both silver bromide emulsions is a gelatin, which is oxidised to reduce the interaction of the gelatin with the grain surfaces.
- 25.0 gram emulsion was added in a stirred vessel at a temperature of 40°C.
- 150.0 ml of a 4% solution of the polymeric compound was added while maintaining a pH of 9.
- 150 ml water was added.
- the D-band reflectance at 593 nm was measured.
- the reflectance values at 593 nm of the fifteen reflectance spectra were added up to obtain the value R s for samples and R ref for the reference.
- the adso ⁇ tion of the polymeric compound on ⁇ 100 ⁇ faces, 'A ⁇ 100 ⁇ ' is represented by an numerical value, calculated by the formula:
- a ⁇ 100 ⁇ ((R 593 s /R 593 ref )-l)*100
- Example IB Measurement of the homodispersity parameter RDA.
- Homodispersity is expressed as RDA, the ratio between the distribution width at half peak height in nanometers and the average aspect ratio.
- the distribution width is determined by disk centrifuge photosedimentometry using a
- Ig of the crystal emulsion is dissolved in 55g of water and 5g of ethanol. To this mixture is added 5ml of a 1% (by weight) detergent solution and 5ml of 0.05% (by weight) Pronase solution.
- the mixture is incubated 10 minutes at 45 degrees Celsius.
- the injected volume is
- the aspect ratio is a value obtained by dividing the diameter of the largest surface area of the individual ⁇ 111 ⁇ tabular grain by the thickness thereof.
- the word "diameter,” used here, is the equivalent circular diameter (ECD), means the diameter of a circle, which has an area equal to the projected area of the grain, which is determined through microscope or electron microscope observation.
- ECD equivalent circular diameter
- an aspect ratio of 8 or more means that the diameter of that circle is 8 or more times greater than the thickness of the grain.
- the homodispersity is expressed as RDA, being the ratio between the grain distribution width in nanometers at half peak height and the average aspect ratio.
- a ⁇ 111 ⁇ tabular silver bromide grain emulsion was prepared as follows: A stirred reaction vessel contained a solution of 1200 ml water, 1.2g of gelatine and 1 .0g potassium bromide. The pH of the solution was adjusted to 9.5 with NaOH and the temperature of the solution was maintained at 40°C. To this solution a 0.47 molar silver nitrate solution and a 0.82 molar potassium bromide solution containing 1.2% of a 200 kD lime bone gelatin were added at identical addition rates of 50 ml/min. The additions were simultaneously stopped after 50 seconds.
- the temperature was increased to 70°C. After 40 minutes of ripening a non-oxidised lime bone gelatine was added, increasing the gelatine concentration to 22.5 weight%. Together with the gelatin an acid solution was added which lowered the pH to 5.0. A total of 1.50 mole of silver nifrate was then added in two separate growth stages. The amount of potassium bromide added during the two growth stages was such that the pBr was between 2.10 and 2.30. The addition rate of all additions was such that no re- nucleation occurred during the growth stage. The grains were washed to remove the excess of salts and gelatine. After the washing 65 g of gelatine was added to the emulsion and the emulsion was stored at 6 degrees C. The resulting emulsion contained ⁇ 111 ⁇ tabular grains having an average thickness of 0.141 micron and an average ECD of 1.56 micron. The peak width at half height is 243nm, resulting in a coefficient of variation (RDA) of 22.1.
- RDA coefficient of
- a ⁇ 111 ⁇ tabular silver bromide grain emulsion was prepared as in example 2, except that in the potassium bromide solution the200 kD lime bone gelatine was replaced by a 30 kD lime bone gelatin, which was prepared by alkaline hydrolysis resulting in random cleaving of peptide bonds.
- the resulting emulsion contained ⁇ 111 ⁇ tabular grains having an average thickness of 0.134 micron and an average ECD of 1.68 micron.
- the peak width at half height is 235nm, resulting in a coefficient of variation
- a ⁇ 111 ⁇ tabular silver bromide grain emulsion was prepared as in example 2, except that in the potassium bromide solution the 200 kD lime bone gelatine was replaced by a 30 kD oxidised lime bone gelatin, said oxidation resulting in a methionine content of less than 5 micromoles per gram gelatin.
- the resulting emulsion contained ⁇ 111 ⁇ tabular grains having an average thickness of 0.118 micron and an average ECD of 1.75 micron.
- the peak width at half height is 275 mn, resulting in a coefficient of variation (RDA) of 18.5, showing some additional improvement in variation.
- a ⁇ 111 ⁇ tabular silver bromide grain emulsion was prepared as in example 2, except that in the potassium bromide solution the 200 kD lime bone gelatine was replaced by a 6.4 kD gelatin lime bone gelatin.
- the 6.4 kD gelatin was obtained by enzymatically hydrolyzing a lime bone gelatin with Trypsine. Trypsine selectively cleaves Arg-X and Lys-X peptide bonds resulting in a gelatin in which the C-terminal amino acid is a Lysine or Arginine.
- the resulting emulsion contained ⁇ 111 ⁇ tabular grains having an average thickness of 0.123 micron and an average ECD of 1.81 micron.
- the peak width at half height is 212nm, resulting in a coefficient of variation (RDA) of 14.4, showing a remarkable improvement in variation.
- a ⁇ 111 ⁇ tabular silver bromide grain emulsion was prepared as in example 2, except that in the potassium bromide solution 6.4 kD inventive gelatin, obtained by hydrolysation with Trypsine, was added to a concentration of 1.2 weight %. In addition to this, 1.2 gram of said inventive gelatin of 6.4kD was added in the stirred reaction vessel before the first silver nitrate and potassium bromide addition.
- the resulting emulsion contained ⁇ 111 ⁇ tabular grains having an average thickness of 0.120 micron and an average ECD of 1.78 micron.
- the peak width at half height is 228nm, resulting in a coefficient of variation (RDA) of 15.4, still showing a remarkable improvement, in variation, but less than adding all inventive gelatin together with potassium bromide.
- Example 7 inventive A ⁇ 111 ⁇ tabular silver bromide grain emulsion was prepared as in example 2, except that in the potassium bromide solution the 200 kD lime bone gelatine was replaced by a 6.4 kD oxidized gelatin lime bone gelatin.
- the 6.4 KD gelatin was obtained by enzymatically hydrolyzing a lime bone gelatin with Trypsine. Trypsine selectively cleaves Arg-X and Lys-X peptide bonds resulting in a gelatin in which the C-terminal amino acid is a Lysine or Arginine. Oxidation resulted in a methionine content of less than 4 micro mol per gram gelatin.
- the resulting emulsion contained ⁇ 111 ⁇ tabular grains having an average thickness of 0.128 micron and an average ECD of 1.68 micron.
- the peak width at half height is 220nm, resulting in a coefficient of variation (RDA) of 16.8, showing a remarkable improvement in variation.
- RDA coefficient of variation
- a ⁇ 111 ⁇ tabular silver bromide grain emulsion was prepared as in example 2, except that in the potassium bromide solution the 200 kD lime bone gelatine was replaced by a 6.6 kD gelatin lime bone gelatin.
- the 6.6 KD gelatin was obtained by enzymatically hydrolyzing a lime bone gelatin with Pronase.
- Pronase a-selectively cleaves Ala-X, Gly-X, Leu-X, Ill-X, Pro-X or Val-X peptide bonds resulting in a gelatin in which only a few percent of the cleavages may result in a Lysine, Arginine or Histidine as N- terminal amino acid.
- the resulting emulsion contained ⁇ 111 ⁇ tabular grains having an average thickness of 0.136 micron and an average ECD of 1.71 micron.
- the peak width at half height is 233nm, resulting in a coefficient of variation (RDA) of 18.5, confirming that enzymatic hydrolysation should not be random but that cleaving specific sites, as done by Trypsine, is necessary.
- RDA coefficient of variation
- a ⁇ 111 ⁇ tabular silver bromide grain emulsion was prepared as in example 2, except that in the potassium bromide solution the 200 kD lime bone gelatine was replaced by a 30 kD acid bone gelatin to which L-Histidine was coupled.
- the resulting emulsion contained ⁇ 111 ⁇ tabular grains having an average thickness of 0.133 micron and an average ECD of 1.67 micron with a coefficient of variation (peak width/AR) of 16.7, showing some additional improvement in variation.
- Table 2 gives an overview of the results of the above experiments.
- the beneficial effect of the invention is clear when the ratio between the distribution width at half height and the average aspect ratio is calculated.
- the volumetric grains size of the ⁇ 11 1 ⁇ tabular grains produced in experiments 2-9 was between 810 and 825nm.
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- Chemical Kinetics & Catalysis (AREA)
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- Spectroscopy & Molecular Physics (AREA)
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Abstract
Description
Claims
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU2003295267A AU2003295267A1 (en) | 2002-12-19 | 2003-12-19 | High bromide {111} tabular grain emulsions with improved dispersity |
JP2005502627A JP2006511847A (en) | 2002-12-19 | 2003-12-19 | High bromide content {111} tabular grain emulsion with improved dispersibility |
US10/538,962 US20060068340A1 (en) | 2002-12-19 | 2003-12-19 | High bromide{111} tabular grain emulsions with improved dispersity |
EP03786421A EP1573394A1 (en) | 2002-12-19 | 2003-12-19 | High bromide 111 tabular grain emulsions with improved dispersity |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
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EP02080452 | 2002-12-19 | ||
EP02080452.2 | 2002-12-19 | ||
EP03075571 | 2003-02-26 | ||
EP03075571.4 | 2003-02-26 |
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WO2004057420A1 true WO2004057420A1 (en) | 2004-07-08 |
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Application Number | Title | Priority Date | Filing Date |
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PCT/NL2003/000914 WO2004057420A1 (en) | 2002-12-19 | 2003-12-19 | High bromide {111} tabular grain emulsions with improved dispersity |
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EP (1) | EP1573394A1 (en) |
JP (1) | JP2006511847A (en) |
AU (1) | AU2003295267A1 (en) |
WO (1) | WO2004057420A1 (en) |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5580712A (en) * | 1995-02-03 | 1996-12-03 | Eastman Kodak Company | Silver halide emulsions, elements and methods of making same using synthetic biopolymer peptizers |
US5989800A (en) * | 1996-11-19 | 1999-11-23 | Fuji Photo Film Co., Ltd | Process for producing tabular silver halide grains |
US6040127A (en) * | 1996-01-10 | 2000-03-21 | Fuji Photo Film Co., Ltd. | Method for producing silver halide emulsion and photographic material containing the same |
EP1178353A1 (en) * | 2000-08-01 | 2002-02-06 | Agfa-Gevaert | Method of preparing ultrathin light-sensitive tabular grain emulsions rich in silver bromide |
WO2002052342A1 (en) * | 2000-12-27 | 2002-07-04 | Fuji Photo Film B.V. | Silver-dispersing polypeptides |
-
2003
- 2003-12-19 EP EP03786421A patent/EP1573394A1/en not_active Withdrawn
- 2003-12-19 JP JP2005502627A patent/JP2006511847A/en active Pending
- 2003-12-19 WO PCT/NL2003/000914 patent/WO2004057420A1/en not_active Application Discontinuation
- 2003-12-19 AU AU2003295267A patent/AU2003295267A1/en not_active Abandoned
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5580712A (en) * | 1995-02-03 | 1996-12-03 | Eastman Kodak Company | Silver halide emulsions, elements and methods of making same using synthetic biopolymer peptizers |
US6040127A (en) * | 1996-01-10 | 2000-03-21 | Fuji Photo Film Co., Ltd. | Method for producing silver halide emulsion and photographic material containing the same |
US5989800A (en) * | 1996-11-19 | 1999-11-23 | Fuji Photo Film Co., Ltd | Process for producing tabular silver halide grains |
EP1178353A1 (en) * | 2000-08-01 | 2002-02-06 | Agfa-Gevaert | Method of preparing ultrathin light-sensitive tabular grain emulsions rich in silver bromide |
WO2002052342A1 (en) * | 2000-12-27 | 2002-07-04 | Fuji Photo Film B.V. | Silver-dispersing polypeptides |
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Publication number | Publication date |
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AU2003295267A1 (en) | 2004-07-14 |
EP1573394A1 (en) | 2005-09-14 |
JP2006511847A (en) | 2006-04-06 |
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