Abstract: An improved, tabular grain radiographic element is described. This element contains a covering power enhancing amount of a thione and exhibits improved covering power and contrast over elements made without the thione.

Abstract: A control process and apparatus for the formation of silver halide grains comprising a mixer disposed outside of a reaction vessel containing an aqueous protective colloid solution and causing a nucleus formation (nucleation) and/or a crystal growth of silver halide grains. The process and apparatus further include: supplying an aqueous solution of a water-soluble silver salt, an aqueous solution of water-soluble halide(s), and an aqueous solution of a protective colloid to the mixer through supply conduits while controlling the flow rates of the solutions; mixing them while controlling the rotational speed of a stirrer of the mixer to form fine, silver halide grains; and immediately supplying the fine grains into the reaction vessel through a conduit connecting the mixer to the reaction vessel to perform the nucleus formation and/or the crystal growth of the silver halide grains in the reaction vessel.

Abstract: A method of controlling a photographic emulsion manufacturing process by non-linear approximation, wherein the set of (k) of a plurality of process inputs, the set (k) of a plurality of states, such as the silver halide concentration, the set (k) of a plurality of process outputs, such as the potential of silver and the pH value, and an evaluation function J (k) are defined, so that a feedback matrix .sub.b (k) and a feed-forward control matrix .sub.f (k) which minimize said evaluation function J (k) are obtained and that manipulated variables which are to be applied to a plant is calculated from the obtained feedback matrix .phi..sub.b (k) and feed-forward matrix .sub.f (k).

Abstract: A process or the preparation of a silver halide photographic emulsion is provided which comprises the addition of at least one pendant type spectral sensitizing dye containing as a substituent a compound having the effect of inhibiting fog at any time after the formation of silver halide grains, but before the completion of the chemical ripening process. In a preferred embodiment, the addition of said pendant type spectral sensitizing dyes is effected at any time after the formation of silver halide grains, but before former one second of the total time of the chemical ripening process. The pendant type spectral sensitizing dyes are compounds represented by the general formula (III) or (IV): ##STR1## wherein SSD represents a sensitizing dye portion; AF represents a compound portion containing a saturated or unsaturated 5- to 7-membered ring containing at least one nitrogen atom; L.sup.1 represents a divalent connecting group containing at least one of C, N, S and O; L.sup.2 has the same meaning at L.sup.

Abstract: The present invention provides (1) a method for preparation of a photographic silver halide emulsion containing tabular silver halide particles having a particle diameter larger than the particle thickness by three times or more, wherein least one oxidizing agent selected from a hydrogen peroxide, a salt of a peroxy acid and an ozone is added to the emulsion before the termination of chemical ripening thereof and then a reducing agent is added thereto, and (2) a silver halide photographic material which has at least one or more layers comprising a tabular silver halide particle-containing emulsion wherein tabular silver halide particles are those prepared by method (1). The present tabular silver halide particle-containing emulsion has high sensitivity and good granularity and is substantially free from fog.

Abstract: A process for the preparation of a photographic emulsion containing tabular silver halide grains having an aspect ratio in the range from 12:1 to 3:1 and a monomodal narrow size distribution comprising:(i) preparing a dispersing medium/bromide mixture having a pBr in the range 0.7 to 1.0,(ii) adding to the mixture silver nitrate and further halide as necessary to maintain an excess of bromide whereby tabular seed grains are formed,(iii) adding ammoniacal base solution to the mixture to achieve at least 0.02N of the base aftr at least 20% by weight of the total silver nitrate has been added,(v) adding further silver nitrate and halide by balanced double jet procedure while maintaining a concentration of ammoniacal base of at least 0.02N, whereby tabular grains are formed.

Abstract: A light-sensitive silver halide photographic material having a support and, provided thereon, photographic component layers including at least one light-sensitive silver halide emulsion layer containing silver halide grains having a silver chloride content of not less tha 90 mole % and having been subjected to gold sensitization, said photographic component layer containing a gelatin of which isoelectric point being 4.0 to 5.0 and the film pH of said photographic component layer being not more than 6.0.

Abstract: A photographic silver halide emulsion is disclosed in which the face centered cubic crystal lattice structure of the grains contain at adjacent cation sites metal ions chosen from group VIII, periods 5 and 6. The metal ions are placed at adjacent cation lattice sites by sensitizing the grains with oligomers each containing at least two of the group VIII metal ions.

Abstract: There is described a method of preparing a silver halide emulsion wherein the silver halide crystals are of the twinned type which comprises the steps of (a) forming or providing in a colloid dispersing medium silver halide crystals containing at least 90 mole % iodide, at least 90% of which are of the hexagonal lattice structure with a mean thickness of less than 0.

Abstract: A method is disclosed for preparing silver halide emulsions useful in photography. Said method comprises the step of precipitating silver halide grains in an aqueous solution of peptizer initially and finally under pAg values suitable for forming cubic silver halide crystals characterized in that at least once during the precipitation stage the pAg is increased for at least 10 percent by weight of the total amount of silver salt used during the precipitation by at least 1.5 units to such value whereby the formation of octahedral crystals would occur if that value were to persist over the entire precipitation stage.Preferably the increase of the pAg value is brought about after precipitation of between ten and twenty percent of the total amount of silver halide to be precipitated.

Abstract: A photochromic material adapted for coating light transmissive materials. The photochromic material contains photosensitive silver halide crystals having dimensions in the range of approximately 50 Angstroms to 800 Angstroms. The silver halide crystals are surface doped with copper ions and another sensitizer selected from mild reducing agents or sulfur-bearing ions. The crystals are dispersed in a protective polymer that does not irreversibly bind halogen.

Abstract: A light-sensitive silver halide photographic material suitably applicable to rapid processing with well-restrained fogging, color fading and degradation in the contrast is disclosed. The material comprises a reflective support and, provided thereon, at least one light-sensitive silver halide emulsion layer which contains (1) silver chloride or silver chlorobromide emulsion of which silver chloride content is not less than 90 mole % and said silver chloride or silver chlorobromide emulsion has been prepared by the addition of a heterocyclic mercapto compound or an azaindene compound during the period of formation of silver halide grains contained therein, (2) a dye-forming coupler and (3) a high-boiling organic solvent of which dielectric constant is not more than 6.

Abstract: A silver halide photographic emulsion is subjected to sulfur or gold-sulfur sensitization in the presence of a combination of (1) at least one of an organic thioether compound or a tetrasubstituted thiourea and (2) a nitrogen-containing heterocyclic compound, to achieve the prevention of pressure desensitization and safelight aptitude deterioration.

Abstract: A photographic element is disclosed comprised of a support and, coated on the support, at least one radiation-sensitive silver halide emulsion comprised of tabular silver halide grains and a dispersing medium. The emulsion includes as a vehicle methacrylate polymer latex capable of reducing pressure sensitivity having a glass transition temperature of less than 50.degree. C.

Abstract: The invention is generally accomplished by providing a tabular silver halide emulsion formation process in which the pH is controlled to greater than 9 by the addition of an alkali base prior to digesting to form uniform nucleated silver bromide particles. In a particularly preferred process the emulsion is adjusted to a pH greater than 9 by the use of sodium hydroxide, digestion takes place in between 3 and 7 minutes, and the emulsion making is completed in less than 100 minutes without the use of ammonium hydroxide. The emulsions formed are suitable for x-ray films and produce the image tone required by radiologists.

Abstract: The present invention relates to a silver halide photographic emulsion comprising silver halide grains dispersed in a binder, wherein grains of 30% or more of a total projected area of all silver halide grains are junctioned silver halide grains, each of the junctioned grains has substantially one junction per grain, and a crystal structure of a substrate grain of the junctioned grain is a rock-salt structure.

Abstract: A silver halide photographic material is described having high speed and excellent latent image storage properties wherein pressure fogging does not readily occur.

Abstract: There is described a method of preparing a silver halide emulsion wherein the silver halide crystals are of the twinned type which comprises the steps of (a) providing in a colloid dispersion medium silver halide crystals containing at least 90% iodide and at least 80% of which are hexagonal lattice structure with each displaying predominantly a single basal face, (b) mixing in the dispersing medium containing the sail silver iodide crystals an aqueous solution of an alkali metal of ammonium bromide or chloride (or mixture thereof) so forming twinned silver halide crystals containing iodide and/or the halide or halides being added, optionally (c) adding a silver halide solvent to the dispersing medium and so causing the growth of the twinned silver halide crystals, and optionally (d) then causing the twinned crystals to increase in size by adding to the colloid dispersing medium further aqueous silver salt solution and further alkali metal or ammonium halide and then finally optionally (e) removing the water-

Abstract: A silver halide photographic material is disclosed which comprises at least one silver halide emulsion layer on a support, wherein light-sensitive silver halide grains in the silver halide emulsion layer or layers are obtained by charging previously prepared silver halide particles having a fine size into a reaction vessel which allows nucleation and/or crystallization of the light-sensitive silver halide grains so that nucleation and/or crystallization are effected in the reaction vessel, and the light-sensitive silver halide grains are subjected to chemical ripening in the presence of a silver halide solvent. A process for the preparation of the silver halide photographic material is also disclosed.

Abstract: An internal latent image type silver halide photographic emulsion comprising internal latent image type silver halide photographic emulsions containing silver halide grains comprising an internal silver halide nucleus which has been doped with metal ions and/or chemically sensitized and an external silver halide shell which covers at least the light-sensitive sites on the internal nucleus, wherein during production of the silver halide grains the pAg at the end of the surface chemical sensitization stage, which is carried out in the presence of sulfur sensitizing agents, is at least 0.4 higher than the pAg at the beginning of the chemical sensitization stage.

Abstract: An improved silver halide photographic material having at least one layer of a light-sensitive silver halide emulsion that is spectrally sensitized with a sensitizing dye of the following general formula (1) to light having a wavelength of 750 nm and above. Said silver halide emulsion is prepared by a process which comprises generating silver halide grains by adding a solution of a water-soluble silver salt and a solution of a water-soluble halide to a solution containing a protective colloid, aggregating the generated silver halide grains with a polymeric flocculating together with the protective colloid, and removing the dissolved matter; ##STR1## where Z.sub.1 and Z.sub.3 each represents the non-metallic atomic group necessary to form an optionally substituted benzothiazole, benzoxazole, naphthothiazole or naphthoxazole nucleus; R.sub.1 and R.sub.2 each represents a saturated or unsaturated aliphatic group; Z.sub.2 represents a 5- or 6-membered ring of carbon atoms; A represents a hydrogen atom when Z.sub.

Abstract: A transmissively read light beam sensitive recording medium is disclosed having a thin layer of irregularly shaped spheroidal silver grains which are capable of being modified by a light beam into smoothly rounded spherical silver grains. Portions of the thin layer which contain the irregularly shaped grains are highly absorptive of light, while portions of the layer which have been modified are transmissive. Also disclosed are methods for creating said medium.

Abstract: The low intensity reciprocity failure characteristics of a silver halide emulsion are improved, without significant reduction of high intensity speed, by incorporating iridium ion into the silver halide grains after or toward the end of the precipitation of the grains in such a way that iridium is below the surface of the grains.

Abstract: A silver halide photographic material having silver halide emulsion layers, at least one of which contains a silver halide emulsion that has been prepared in such a way that a spectral sensitizing dye is added after 85 wt % of the soluble silver salt in solution that is to be added during ripening of silver halide emulsion has been added but before the start of a desalting step, and that a spectral sensitizing dye which may be the same or different from the first added dye is added during the desalting step.

Abstract: The production of a photosensitive silver halide emulsion by precipitation of the silver halide in the presence of gelatine, flocculation and washing of the silver halide precipitated in the presence of the gelatine and redispersion with addition of more gelatine, precipitation being carried out in the presence of a gelatine having a gold number of at most 10 .mu.mol/g gelatine and a cysteine content of at most 6 ppm and redispersion being carried out with a gelatine having a gold number of at least 23 .mu.mol/g gelatine, leads to an emulsion of uniform grain distribution in which undesirably high fogging is avoided.

Abstract: A silver halide light-sensitive photographic material having a support and provided thereon, hydrophlic colloidal layers including at least one silver halide light-sensitive emulsion layer is disclosed. The silver halide emulsion layer comprises a silver halide emulsion (I) prepared by adding a high-molecular flocculant under at least one of Conditions (1) through (3) to a silver halaide emulsion (II) prepared by a water-soluble silver salt solution and a water-soluble halide solution to a protevtive colloid solution so as to flocculate and settle a silver halide grain together with a protective colloid for desalting of dissolved substances, and by dispersing again the desalted silver halide emulsion in a protective colloid solution;Condition (1): a temperature of the silver halide emulsion (II) is not lower than 30.degree. C.

Abstract: A silver halide photographic light-sensitive material includes a support having thereon at least one silver halide light-sensitive emulsion layer, characterized in that at least one of a plurality of emulsions contained in the emulsion layer contains tabular grains having a thickness of less than 0.5 .mu.m, a diameter of at least 0.3 .mu.m, and an average ratio of grain diameter to grain thickness of at least 2, the tabular grains occupy at least 50% of the entire projected area of all the grains contained in the emulsion, the surfaces of the grains are chemically sensitized, and a ratio of surface sensitivity to internal sensitivity of the grains is 0.5 to 2.

Abstract: A method of producing a silver halide photographic emulsion including the step of:reacting a water-soluble silver salt and at least one water-soluble halide salt containing chloride in aqueous solution in the presence of at least one compound represented by formulae (I) or (II): ##STR1## wherein A.sub.1, A.sub.2, A.sub.3 and A.sub.4, which may be the same or different, each represents a nonmetallic atomic group necessary for forming a substituted or unsubstituted heterocyclic ring; B represents a divalent linking group; R.sub.1 and R.sub.2, which may be the same or different, each represents an alkyl group; X represents an anion necessary for charge balance; m is 0 or 1; and n is 0 or 1;to form light-sensitive silver halide grains having a silver chloride content of at least 50 mol %, selected from octahedral grains, tetradecahedral grains and tablular grains, wherein at least 30% of the surface area of said light-sensitive silver halide grains is composed of (111) planes.

Abstract: A silver halide photographic material is disclosed, comprising a support having thereon at least one hydrophilic colloid layer at least one of which must be a gold- and sulfur-sensitized silver halide emulsion layer, said silver halide emulsion layer containing from 0.1 to 3.0 mol % silver iodide per mol of silver, wherein said silver halide emulsion comprises silver halide grains having a substantial core/shell structure wherein the silver iodide content in the shell is less than that in the core, and the silver halide emulsion layer or other hydrophilic colloid layer contains a polymer represented by the formula (I)--(A).sub.x (B).sub.y (C).sub.

Abstract: Photographic silver halide emulsions are disclosed comprised of radiation sensitive silver halide grains exhibiting a face centered cubic crystal lattice structure internally containing oxo coordination ligands and a transition metal chosen from groups 6, 7, and 8 of the periodic table of elements.

Abstract: A silver halide emulsion comprising a binder and silver halide grains, wherein the projected area of substantially circular tabular silver halide grains having two parallel twin planes to the basal planes having a linear ratio of 0 to 4/5 accounts for from 70% to 100% of the projected area of the whole silver halide grains, and further the circular tabular silver halide grains are monodisperse grains.The emulsion has good aging stability.

Abstract: A silver halide photographic emulsion comprising a hydrophilic colloid having dispersed therein tabular silver halide grains having an aspect ratio of at least 2, the grains comprising a matrix comprising at least 50 mol % silver bromide ions based on silver ions, and a high silver chloride layer on the matrix, the high silver chloride layer comprising at least 50 mol % chloride ions based on silver ions and forming a substantially uniform plane on the matrix, wherein at least 50 mol % of the high silver chloride layer is present on two basal plane surfaces of the matrix.The emulsion has improved pressure properties which are suited for rapid processing, and minimized grain aggregation and excellent suitability for preparation.

Abstract: A photographic material comprising a support and at least one photosensitive silver halide emulsion layer, the silver halide grains of this silver halide emulsion layer having a layered structure of at least two layers, which extend to the surface of the grain, and being selectively etched, is distinguished by improved sensitivity and reduced fogging.

Abstract: A photographic silver bromoiodide emulsion comprises a dispersing medium and a silver bromoiodide that (a) is monodispersed, cubic grain silver bromoiodide; (b) has a grain size within the range of 0.1 to 0.7 micron; (c) contains 1 to 7 mole percent iodide; and, (d) is prepared by a process comprising (i) forming the silver bromoiodide grains by mixing, in the presence of a thioether ripening agent, silver salt and alkali metal bromide and iodide salts until 60 to 90% of the silver salts have been added; then, (ii) carrying out the remainder of the silver bromoiodide grain formation with the addition of silver salt and alkali metal bromide and iodide salts that are no more than 1 mole percent iodide; wherein the resulting silver bromoiodide grains have no discernible shell as analyzed by x-ray diffraction. Such photographic silver bromoiodide emulsions are useful in photographic silver halide materials to provide longer exposure latitude.

Abstract: A direct positive photographic light-sensitive material is disclosed which comprises at least two direct positive emulsion layers having the same color sensitivity, wherein at least one hydrophilic colloid layer is provided between the direct positive emulsion layers. A direct positive photographic light-sensitive material having a high graininess, a soft tone, and a high picture quality can be obtained.

Abstract: A silver halide photographic emulsion containing silver halide grains having (III) faces, at least 50% (by projected area) of which are(a) silver halide grains controlled so that the development thereof is initiated at the corners or in the vicinity of the corners of the grains, and/or(b) silver halide grains controlled so that the development thereof is initiated at the edges or in the vicinity of the edges of the grains.

Abstract: A silver halide photographic emulsion is disclosed. The emulsion contains core/shell type silver halide grain comprising a core essentially consisting of silver iodobromide and at least one shell essentially consisting of silver iodobromide or silver bromide, in which said silver halide emulsion have an average silver iodide content of less than 7 mol %, and said core has a silver iodide content of not less than 10 mol % a shell arranged at the outermost portion of said shell has a silver iodide content of not more than 5 mol %, and said core and shell have a distinct core/shell structure. The emulsion is excellent in developing activity, ready in contrast control and excellent in processing stability, with out deteriorating both sensitivity and pressure resistance property.

Abstract: A silver halide photographic material comprising a support having thereon at least one silver halide emulsion layer containing at least one emulsion in which chemically sensitized silver halide grains are composed of tabular silver halide grains having a diameter of a circle corresponding to the projected area of at least 0.4 .mu.

Abstract: A photographic light-sensitive material comprising, on a support, at least one silver halide emulsion layer containing silver halide grains, wherein at least 50% of the total projected surface area of silver halide grains contained in the silver halide emulsion layer is occupied by tabular grains comprising at least about 50 mol% of silver chloride, the tabular grains having been precipitated in the presence of a dye and having an aspect ratio of at least 2.

Abstract: A light-sensitive emulsion layer comprising a dispersing medium and silver halide grains, wherein at least 10% of the total projected area of the silver halide grains is formed by silver bromo-iodide grains bounded by at least one substantially concave-shaped major crystal face, having a diameter of at least 0.6 .mu.m and the half of their thickness, in the deepest point of said concavity, of less than 80% of the half of their border thickness. Photographic elements comprising a support base and at least one such emulsion layer are shown.

Abstract: A photographic light-sensitive material comprises a support having thereon at least one silver halide emulsion layer. At least 70% of a total number of silver halide grains contained in the emulsion layer are regular crystal grains not having a twinning plane. At least 50 mol% of the regular grains are silver chloride. The regular crystal grains have a (111) crystal plane on 30% or more of a total grain surface and are chemically sensitized in the presence of a gold compound or sulfur and gold compounds.

Abstract: A silver halide emulsion containing at least 20 wt %, on the basis of the total silver halide, of rod-like or needle-like crystal grains and/or crystal grains each formed by joining at least two of said rod-like or needle-like crystal grains at right angles or in paralle, said rod-like or needle-like crystal grains each being defined by the crystal planes consisting essentially of the (100) faces, wherein, when a ratio of length of the edges along which said planes intersect is taken as l:m:n in the order of from the smallest to the largest, m and n satisfy the following relationships (I) and (II):1.ltoreq.m.ltoreq.7 (I)n.gtoreq.

Abstract: A silver halide photographic emulsion comprising silver halide grains is disclosed, wherein at least 60% of the total projected area of the silver halide grains is comprised of tabular silver halide grains having a central portion and an outer portion, of which the iodide content of the central portion is from 7 mol % to the solid solution limit, and which have two parallel twinned crystal planes.A method for the manufacture of the silver halide emulsion is also disclosed, which comprises the steps of nucleating the silver halide grains under conditions where the gelatin concentration in the reaction solution is set at from 0.1 to 20 wt %, the addition rates of the silver salt and the halide are set at from 6.times.10.sup.-4 to 2.9.times.10.sup.-1 mol/minute per liter of reaction solution, and the pBr value in the reaction solution is set at from 1.0 to 2.5, Ostwald ripening the nucleated grains, and then growing the thus ripened grains.

Abstract: A light-sensitive material comprising a light-sensitive layer which contains silver halide grains, a reducing agent and a polymerizable compound provided on a support, characterized in that the silver halide grains have such a grain size distribution that the coefficient of variation (.sigma./r) is not more than 20% wherein .sigma. means a standard deviation of the grain size and r means an average grain size. Image-forming methods employing the light-sensitive material are also disclosed.

Abstract: Monocrystalline lanthanum orthogallate grown along a predetermined crystallographic direction in the form of a single crystal of a size greater than 1 cm in diameter/width and at least 10 cm in length is described. Also described is a class of perovskite type monocrystalline compositions which are readily grown from a pure melt along a predetermined crystallographic direction. Such perovskite-type monocrystalline compositions have the following formulae:LaGa.sub.1-x Sc.sub.x O.sub.3 1.LaGa.sub.1-x Al.sub.x O.sub.3 2.LaGa.sub.1-x In.sub.x O.sub.3 3.wherein x=0.001 to 0.5. Additionally described is a class of perovskite-type monocrystalline compositions of the following formula:R.sub.x La.sub.1-x GaO.sub.3wherein R is a rare earth element of smaller ionic radius than La and wherein x=0.001 to 0.5. Further described is a class of perovskite-type monocrystalline compositions of the following formulae:R.sub.x La.sub.1-x Ga.sub.1-y Al.sub.y O.sub.3R.sub.x La.sub.1-x Ga.sub.1-y Sc.sub.y O.sub.3R.sub.x La.sub.1-x Ga.

Abstract: Photographic silver halide emulsions are disclosed comprised of radiation sensitive silver halide grains containing greater than 50 mole percent chloride and less than 5 mole percent iodide, based on total silver, with any residual halide being bromide, said grains exhibiting a face centered cubic crystal lattice structure formed in the presence of a hexacoordination complex of rhenium, ruthenium, or osmium with at least four cyanide ligands. The emulsions exhibit increased sensitivity.

Abstract: The present invention is directed to a process of precipitating for use in photography a silver halide emulsion employing a gelatino-peptizer containing alkylated methionine and to an emulsion produced by this process. A variety of advantages can be realized, including an increase in the population of twinned grains and a higher yield of thin tabular grains.

Abstract: An ultra-high contrast silver halide photographic material which is suitable for daylight use and which has at least one silver halide emulsion layer on a support, wherein the emulsion layer contains cubic silver halide grains having a mean grain size of 0.15 .mu.m or less and containing silver chloride in an amount of 99 mol % or more. The material can contain a rhodium salt or an organic desensitizer for lowering the sensitivity while maintaining the high contrast photographic property thereof.

Abstract: Photographic emulsions are disclosed comprised of radiation sensitive silver bromide grains optionally containing iodide. The grains exhibit a face centered cubic crystal lattice structure and are formed in the presence of a hexacoordination complex of rhenium, ruthenium, or osmium with at least four cyanide ligands.

Abstract: Photographic silver halide emulsions are disclosed comprised of radiation sensitive silver halide grains exhibiting a face centered cubic crystal lattice structure internally containing a nitrosyl or thionitrosyl coordination ligand and a transition metal chosen from groups 5 to 10 inclusive of the periodic table of elements.