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WO1996013759A2 - Emulsions a grains tabulaires avec conversions d'halogenure sur des sites selectionnes et procedes de preparation desdites emulsions - Google Patents

Emulsions a grains tabulaires avec conversions d'halogenure sur des sites selectionnes et procedes de preparation desdites emulsions Download PDF

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Publication number
WO1996013759A2
WO1996013759A2 PCT/US1995/012522 US9512522W WO9613759A2 WO 1996013759 A2 WO1996013759 A2 WO 1996013759A2 US 9512522 W US9512522 W US 9512522W WO 9613759 A2 WO9613759 A2 WO 9613759A2
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WO
WIPO (PCT)
Prior art keywords
halide
grains
iodide
tabular
percent
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US1995/012522
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English (en)
Other versions
WO1996013759A3 (fr
Inventor
David Earl Fenton
Lucius Seiberling Fox
Donald Lee Black
Seshadri Jagannathan
Samuel Chen
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Eastman Kodak Co
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Eastman Kodak Co
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Filing date
Publication date
Priority claimed from US08/329,591 external-priority patent/US5476760A/en
Application filed by Eastman Kodak Co filed Critical Eastman Kodak Co
Priority to JP8514580A priority Critical patent/JPH09507591A/ja
Priority to DE69526202T priority patent/DE69526202T2/de
Priority to EP95936216A priority patent/EP0737329B1/fr
Publication of WO1996013759A2 publication Critical patent/WO1996013759A2/fr
Publication of WO1996013759A3 publication Critical patent/WO1996013759A3/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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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
    • G03C1/46—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein having more than one photosensitive layer
    • 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
    • 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
    • G03C1/06—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein with non-macromolecular additives
    • G03C1/07—Substances influencing grain growth during silver salt formation
    • 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
    • G03C1/06—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein with non-macromolecular additives
    • G03C1/08—Sensitivity-increasing substances
    • G03C1/10—Organic substances
    • G03C1/12—Methine and polymethine dyes
    • 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
    • G03C5/00—Photographic processes or agents therefor; Regeneration of such processing agents
    • G03C5/16—X-ray, infrared, or ultraviolet ray processes
    • G03C5/17—X-ray, infrared, or ultraviolet ray processes using screens to intensify X-ray images
    • 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
    • G03C1/06—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein with non-macromolecular additives
    • G03C1/08—Sensitivity-increasing substances
    • 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
    • G03C1/06—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein with non-macromolecular additives
    • G03C1/08—Sensitivity-increasing substances
    • G03C1/10—Organic substances
    • G03C1/12—Methine and polymethine dyes
    • G03C1/14—Methine and polymethine dyes with an odd number of CH groups
    • G03C1/18—Methine and polymethine dyes with an odd number of CH groups with three CH groups
    • 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
    • G03C1/035—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein characterised by the crystal form or composition, e.g. mixed grain
    • G03C2001/03535—Core-shell grains
    • 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
    • G03C1/035—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein characterised by the crystal form or composition, e.g. mixed grain
    • G03C2001/03558—Iodide content
    • 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
    • G03C1/035—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein characterised by the crystal form or composition, e.g. mixed grain
    • G03C2001/03588—Polydisperse emulsion
    • 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
    • G03C1/06—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein with non-macromolecular additives
    • G03C1/08—Sensitivity-increasing substances
    • G03C2001/0845—Iron compounds
    • 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
    • G03C1/06—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein with non-macromolecular additives
    • G03C1/08—Sensitivity-increasing substances
    • G03C1/09—Noble metals or mercury; Salts or compounds thereof; Sulfur, selenium or tellurium, or compounds thereof, e.g. for chemical sensitising
    • G03C2001/093—Iridium
    • 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
    • G03C1/06—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein with non-macromolecular additives
    • G03C1/08—Sensitivity-increasing substances
    • G03C1/09—Noble metals or mercury; Salts or compounds thereof; Sulfur, selenium or tellurium, or compounds thereof, e.g. for chemical sensitising
    • G03C2001/094—Rhodium

Definitions

  • the invention relates to radiation-sensitive silver halide emulsions useful in photography and to processes for their preparation.
  • Silver halide emulsions contain silver halide grains in a dispersing medium, which typically contains a gelatino-vehicle. Although the majority of the silver and halide ions are confined to the grains, at equilibrium a small fraction of the silver and halide ions are also present in the dispersing medium, as illustrated by the following relationship: (I)
  • -log Ksp pAg + pX
  • pAg represents the negative logarithm of the equi ⁇ librium silver ion activity
  • pX represents the negative logarithm of the equi ⁇ librium halide ion activity
  • silver halide grains can be modified by halide conversion. This is accomplished by introducing into a silver halide emulsion halide ions that have a lower solubil ⁇ ity than halide ions contained in the grains.
  • silver chloride grains can be transformed into converted halide grains by the introduction of bromide and/or iodide ions.
  • similarly silver bromide grains can be transformed into converted halide grains by the introduction of iodide ions.
  • Ikeda et al U.S. Patent 4,806,461 reported that when at least 50 percent of total grain projected area is accounted for by tabular grains containing 10 or more dislocations per grain improved photographic sensitivity is observed.
  • the dislocations reported by Ikeda et al were more or less randomly distributed over the major faces of the tabular grains.
  • Nakamura et al U.S. Patent 5,096,806 discloses a tabular grain emulsion that has been modi- fied by halide conversion to create a somewhat higher concentration of iodide ions in the vicinity of the grain corners than elsewhere along their edges. From the Examples it is apparent that the iodide content is only slightly higher in the corner regions than else- where along the grain edges. Examples 1 and 2 show corner region iodide concentrations of 9.8 and 10.1 mole percent versus edge region iodide concentrations of 7.1 mole percent.
  • Figure 1 is a plan view of a tabular grain, showing the demarcation between a corner region and the remainder of the tabular grain.
  • the present invention provides a process for the halide conversion of tabular grain emulsions that achieves selective displacement of halide ions with iodide ions within the corner regions of high bromide tabular grains accounting for at least 70 percent of the total grain projected area of the emulsion in which they are contained. Both the process for achieving exclusive siting of halide conversion dislocations within the corner regions of tabular grains accounting for at least 70 percent of total grain projected area and the emulsions that result are the subject of this invention.
  • this invention is directed to a halide conversion process comprised of (1) providing a radiation-sensitive emulsion containing a gelatino- vehicle and silver halide grains and (2) introducing iodide ions into the grains, characterized in that (3) the radiation-sensitive emulsion as provided includes tabular grains which (a) are comprised at least 90 mole percent bromide and up to 10 mole percent iodide, based on silver, and (b) have ⁇ 111 ⁇ major faces that (i) form corners joined by linear edges and (ii) account for at least 70 percent of total grain projected area, (4) the pBr of the emulsion provided is maintained at less than 3.5, (5) an iodide ion source exhibiting a second order reaction rate constant with the gelatino-vehicle of less than 10" ⁇ mole ⁇ l sec" ⁇ - is introduced into the emulsion and reacted with the gelatino-vehicle to release iodide ions, and (6)
  • this invention is directed to a radiation-sensitive emulsion containing a gelat ⁇ ino-vehicle and silver halide grains characterized in that the grains are comprised of tabular grains accounting for at least 70 percent of total grain projected area (1) comprised of at least 90 mole percent bromide and up to 12 mole percent iodide, based on total silver, (2) having ⁇ 111 ⁇ major faces that form corners joined by linear edges, and (3) containing halide conversion dislocations that are confined to corner regions, the boundary between each corner region and the tabular grain of which it forms a part being delineated by a plane that perpendicularly intersects an axis extending from the center of a ⁇ 111 ⁇ major face of the tabular grain to the tabular grain corner of the corner region at a distance from the corner which is 10 percent of the length of the axis.
  • the invention offers a number of advantages that can be realized in one or more of its various forms.
  • the formation of nontabular protru- sions on the tabular grains that can degrade the desired tabular structural form (morphology) of the grains is avoided.
  • Exclusively siting the halide conversion dislocations in the corner regions of the tabular grains utilizes the dislocations with maximum efficiency, since the corner region siting of the dislocations represents optimum siting for sensitivity enhancement.
  • unwanted pressure sensitivity a function of locally applied pressure
  • any tendency toward roughening of the major faces of the tabular grains or reversion of the tabular grains to nontabular forms by halide conversion is entirely avoided when the majority of the major faces contain no halide conversion dislocations.
  • iodide ion sources exhibiting lower reaction rate constants than conventional iodide ion sources
  • control over halide conversion is facili- tated and improved.
  • an exact set of conditions will produce a desired result, but any one or combination of small inadvertent manu ⁇ facturing variances from these conditions have a large and unwanted impact on the characteristics of the emul- sion obtained.
  • the halide conversion process of the invention is more robust (i.e., less subject to product variance as a function of inadvertent manufacturing variances in precipitation conditions) .
  • the slower release of iodide ion enhances manufacturing robustness.
  • With slower rates of iodide ion release batch-to-batch and scale-to-scale variances in emulsion properties are reduced, and the impact of varied stir ⁇ ring rates during halide conversion is reduced.
  • iodide release does not produce any by-product requiring subsequent elimination from the emulsion (e.g., by a subsequent washing step). It is, in fact, contemplated to modify usefully the gelat ⁇ ino-vehicle in the halide conversion operation. Additionally, it has been recognized that superior photographic performance is realized when pBr levels are maintained at less than 3.0 during halide conversion.
  • the present invention is directed to improved processes for achieving the halide conversion of high bromide ⁇ 111 ⁇ tabular grain emulsions and to novel converted halide emulsions that these processes make possible.
  • high bromide refers to silver halide grains or emulsions that contain at least 90 mole percent bromide, based on total silver.
  • Contemplated silver halide compositions of the tabular grains provided for halide conversion are silver bromide, silver iodobromide, silver chloro- bromide, silver iodochlorobromide and silver chloro- iodobromide emulsions.
  • the halides are named in order of ascending concentrations.
  • Silver bromide emulsions represent one specifically preferred tabular grain emulsion selection for halide conversion.
  • the tabular grains initially contain no more than 10 mole percent iodide.
  • Halide conversion can be achieved when the tabular grains contain higher levels of iodide, particularly when the higher levels of iodide are confined to the interior of the tabular grains, but maximum photographic advantages are real ⁇ ized when iodide is initially limited. It is specifi- cally preferred that the tabular grains initially contain less than 5 mole percent iodide. It is also preferred that the distribution of surface iodide be uniform.
  • iodide ions in the tabular grains is in itself somewhat disruptive of the face centered cubic rock salt struc ⁇ ture of the crystal lattice provided by bromide (optionally in combination with chloride) ions. Uniform distribution at or near the grain surface as well as limiting iodide surface concentrations assures that iodide initially in the tabular grain structure minimally influences subsequent halide conversion. As most conveniently formed the tabular grains provided for halide conversion contain iodide that is uniformly distributed throughout the grain.
  • Chloride when present is preferably uniform ⁇ ly distributed at the grain surfaces and, most prefer ⁇ ably, throughout the grains.
  • tabular grain is employed to identify a grain that has two parallel major faces that are clearly larger than any remaining faces of the grain and that exhibits an aspect ratio of at least 2. Aspect ratio is the quotient of tabular grain equivalent circular diameter (ECD) divided by tabular grain thickness (t) .
  • tabular grains satisfying ⁇ 111 ⁇ major face and composition require ⁇ ments account for at least 70 percent (preferably at least 90 percent) of total grain projected area.
  • substantially all (e.g., >97%) of total grain projected area be accounted for by tabular grains.
  • the tabular grain emulsions selected for halide conversion can have mean ECD's, tabular grain thicknesses and aspect ratios of any conventional value.
  • ECD's cannot exceed 10 ⁇ m.
  • ECD's are less than 5 ⁇ m.
  • Minimum ECD's are determined by the minimum aspect ratio of 2 and the mean thickness of the tabular grains.
  • tabular grains having a thickness of less than 0.3 ⁇ m account for at least 70 percent of total grain projected area.
  • thin tabular grain emulsions those in which tabular grains having a thickness of less than 0.2 ⁇ m account for at least 70 percent of total grain projected area.
  • ultrathin tabular grain emulsions particularly for minus blue (green and/or red) record ⁇ ing.
  • Ultrathin tabular grain emulsions are those in which tabular grains having a thickness of less than 0.07 ⁇ account for at least 70 percent of total grain projected area.
  • high bromide tabular grain emulsions for halide conver- sion to limit grain dispersity. It is preferred that the coefficient of variation (COV) of grain ECD be less than 30 percent, most preferably less than 20 percent. With care high bromide tabular grain emulsions can be prepared with COV's of less than 10 percent.
  • the tabular grain emulsions upon which halide conversion is practiced are those in which the tabular grains have ⁇ 111 ⁇ major faces that form corners joined by linear edges. The ⁇ 111 ⁇ major faces of the tabular grains lie in ⁇ 111 ⁇ atomic planes. Typically these tabular grains in their most regular form have hexagon ⁇ al major faces. Tabular grains with triangular ⁇ 111 ⁇ major faces are also quite common.
  • tabular grains with trape ⁇ zoidal (truncated triangle) major faces Somewhat less common, but also known, are tabular grains with trape ⁇ zoidal (truncated triangle) major faces. Tabular grains almost always exhibit some rounding at their corners due to ripening. However, in the emulsions of the invention, both before and after halide conversion, corner rounding is limited so that linear edges joining the corners are always in evidence. For example, tabu- lar grains with several corners and linear edges approximating those of a hexagonal major face, but also including a rounded edge or edges resulting in less than 6 corners and 6 linear edges are specifically excluded from the tabular grains required to account for at least 70 percent of total grain projected area.
  • the corner of a tabular grain is defined as an edge region of a ⁇ 111 ⁇ major face that exhibits (or approximates) a radius of curvature that is less than half the radius (ECD + 2) of the tabular grain ⁇ 111 ⁇ major face--i.e., less than the tabular grain ECD + 4.
  • Linear edges are those that extend from one corner region to the next without interruption and are linear in appearance. It is additionally preferred that the tabular grains of the emulsions selected for halide conversion according to the teachings of the invention contain a minimal number of dislocations in their ⁇ 111 ⁇ major faces.
  • the tabular grains that account for at least 70 percent (most preferably at least 90 percent) of total grain projected area contain fewer than 10 dislocations per grain.
  • the tabular grains accounting for at least 70 percent (most preferably at least 90 percent) of total grain projected area are free of observable dislocations. Exemplary descriptions of grain disloca ⁇ tions and their observation are provided by
  • the emulsion selected for halide conversion includes a dispersing medium containing a gelatino-vehicle.
  • vehicle is employed in its art recognized sense to indicate an emulsion material capable of acting as a peptizer or a binder.
  • gelatino-vehicle refers to gelatin (e.g. , cattle bone or hide gelatin), acid-treated gelatin (e.g., pigskin gelatin), or a gelatin derivative (e.g., acetylated or phthalated gelatin) .
  • the silver halide grains are precipitated in the presence of a small amount of a gelatino-vehicle, which acts as a peptizer. At or near the completion of grain precipitation it is common practice to increase the concentration of the gelatino-vehicle.
  • a gelatino-vehicle acts as a peptizer.
  • halide conversion as contemplated by this invention is undertaken at the conclusion of precipitation before any other steps are taken to prepare the emulsions for final use--e.g., washing, chemical and/or spectral sensitization, or incorporation of modifying addenda.
  • the gelatino-vehicle can, if desired, be present in combination with other conventional photo ⁇ graphic emulsion vehicles. It is preferred that the gelatino-vehicle contain natural levels of methionine, typically in excess of 100 micromoles per gram, since these facilitate the halide conversion process of the invention. Conversely, gelatino-vehicles that have been treated with strong oxidizing agents, such as hydrogen peroxide or an alkylating agent, to eliminate methionine by oxidation are not preferred.
  • a remarkable feature of tabular grain emul- sions that have undergone halide conversion by the method of the invention is that grain dislocations produced by halide conversion are confined to corner regions of the tabular grains accounting for at least 70 (preferably at least 90) percent of total grain projected area.
  • a grain corner is a surface feature of a grain
  • a corner region is a portion of a grain that lies next to and forms the corner.
  • corner regions are easily identified as such by visual inspection of grain magnifications, to provide a quan- titative definition, the corner region of a tabular grain is that portion of the tabular grain that lies adjacent the edges of the grain defining a corner.
  • the corner region is separated from the remainder of the tabular grain of which it forms a part by a boundary that lies in a plane perpendicularly intersecting an axis extending from the center of a ⁇ 111 ⁇ major face of the tabular grain to the tabular grain corner of the corner region.
  • the plane is located at a distance from the corner that is 10 percent of the length of the axis.
  • FIG. 1 An illustration of a typical corner region and its boundary are provided in Figure 1.
  • a tabular grain 100 having a hexagonal major face 102 lying in a ⁇ 111 ⁇ atomic plane is shown with six linear edges 104a, 104b, 104c, 104d, 104e and 104f.
  • An axis 106 is shown extending from the center C of the ⁇ 111 ⁇ major face to a corner 108 formed by the intersection of the edges 104a and 104f.
  • a plane 110 is shown perpendicularly intersecting the axis at point 112. The plane is located so that the distance between corner 108 and point 112 is exactly 10 percent of the total length of the axis 106 extending from the center C and the corner 108.
  • the plane which extends downwardly through the thickness of the tabular grain, provides a demarcation of the corner region 114, shown as the triangular area bounded by the edges 104a and 104f and the plane 110.
  • corner region 114 there are five additional corner regions identical to corner region 114.
  • the six (6) corner regions together account for less than 2.5 percent of the total volume of the tabu ⁇ lar grain. Thus, halide conversion is severely restricted as to the portion of the tabular grain it can occupy.
  • halide conversion can be confined to corner regions of the tabular grains by introducing iodide ion into the emulsion under conditions that maintain the equilibrium corner preference for halide incorporation from the surrounding dispersing medium. This requires limiting the presence of free iodide ion within the dispersing medium of the emulsion.
  • One possible technique for accomplishing this is to introduce highly dilute solutions of iodide ion into the dispersing medium.
  • the iodide ion that is present displaces more soluble halide ion from the tabular grains, but, by limiting the concentration of the iodide, the rate of halide conversion can be moder ⁇ ated to achieve halide conversion exclusively in the corner regions of the tabular grains accounting for at least 70 percent of total grain projected area.
  • this approach in practice exhibits disadvan ⁇ tages.
  • concentration of iodide ion must be maintained at less than 10 -5 molar. Therefore large amounts of diluent (typically water) must be subsequently removed from the emulsion by wash ⁇ ing. Additionally washing is required for counter ion (e.g., ammonium or alkali cation) removal.
  • counter ion e.g., ammonium or alkali cation
  • the desired exclusive corner region halide conversion without degradation of the desired geometrical form of the tabular grains, can be achieved without the above disadvantages by employing as an iodide ion source a compound that is capable of reacting with the gelatino- vehicle at a limited rate. Large non-equilibrium excesses of iodide ions that would cause equilibrium siting preferences to be obliterated are avoided. Also, excessive dilution of the dispersing medium is avoided. Still further, the non-iodide moiety of the iodide releasing compound is captured by the gelatino- vehicle, thereby avoiding any unwanted interaction of reaction by-products with the grains or subsequently provided addenda. This also eliminates any necessity of emulsion washing after halide conversion to remove reaction by-products.
  • the iodide ion source compound can take the form of an organic iodide: (IV)
  • R-I where R is an organic moiety providing a carbon to iodide bond.
  • the suitability of the R-I organic iodide releasing compound can be explained in terms of its low second order reaction rate constant in interacting with gelatino-vehicle.
  • the second order reaction rate constant is less than 10 ⁇ 3 mole ⁇ l-sec ⁇ l.
  • [R-I] is the molar concentration in moles per liter of R-I, defined above.
  • [G-V] is the molar concentration in moles per liter of gelatino-vehicle.
  • a typical average molecular weight of a photographic gelatino-vehicle of 1 X 10 ⁇ daltons can be alternatively employed.
  • the gelatino-vehicle being an amino-acid polymer, contains numerous reaction sites. Divalent sulfur atoms, such as found in methionine, and triva- lent nitrogen atoms provide iodide reaction sites.
  • Preferred organic moieties (R) are those that are relatively water soluble. Typically such compounds contain 10 or fewer carbon atoms. Although the iodide substituent itself promotes water solubility, at least one additional polar substituent is preferred to promote solubility, particularly when R contains three or more carbon atoms.
  • suitable iodide ion releasing compounds include the following: IRC-1 ⁇ -Iodoacetic acid IRC-2 ⁇ -Iodoacetamide IRC-3 Iodomethane IRC-4 Iodocyanomethane IRC-5 1-Acetophenone
  • IRC-6 3-Iodopropanoic acid
  • IRC-7 4-Iodobutanoic acid
  • IRC-8 2-(Iodomethyl)pyridine
  • IRC-9 Iodomethylbenzene
  • IRC-10 l-Iodo-2-hydroxypropane
  • IRC-11 2-Iodoethanol
  • IRC-12 3-Iodopropanol
  • IRC-13 4-Iodobutanol
  • pBr is most preferably maintained at less than 2.5 and optimally at less than 2.0 during halide conversion.
  • a minimum pBr for high bromide tabular grain precipitation is typically 0.6. Hence this represents a convenient lower pBr for halide conversion as well, although halide conversion at still lower pBr values is possible, if desired. If pBr is 3.0 or higher, it is contemplated to maintain pH on the acid side neutrality--that is, less than 7.
  • each grain must retain corners joined by linear edges and contain dislocations produced by halide conversion confined to one or more corner regions.
  • the present invention effectively eliminates degradation of tabular grain geometries by halide conversion. Dislocations on major faces of the tabular grains are avoided. Extensive edge degradation of the tabular grains is also avoided, such as evidenced by non-linear edges and obliteration of one or more grain corners present in the host tabular grains before halide conversion.
  • the converted halide emulsions of the invention are preferably limited to a maximum iodide concentration of 12 (optimally 5) mole percent, based on total silver. Higher levels of iodide inclusion are possible, but do not enhance photographic performance for the most commonly encountered photographic applications. At the other extreme, performance enhancements can be realized when silver bromide host tabular grain emulsions receive iodide by halide conversion to increase iodide ion concentrations to only 0.5 mole percent, based on total silver. In fact, only small amounts of iodide incorporation are required to improve the properties of the tabular grain emulsions chosen for halide conver ⁇ sion. It is preferred to increase the iodide concen ⁇ tration of the tabular grains by halide conversion by from 0.5 to 5 mole percent, optimally from 1.0 to 3 mole percent.
  • the emulsions of the invention can be prepared for photographic use as described by Research Disclosure, 36544, cited above, I. Emulsion grains and their preparation, E. Blends, layers and performance categories; II. Vehicles, vehicle extenders, vehicle-like addenda and vehicle related addenda; III. Emulsion washing; IV. Chemical sensitization; and V. Spectral sensitization and desensitization, A. Spectral sensitizing dyes.
  • the emulsions or the photographic elements in which they are incorporated can additionally include one or more of the following features illustrated by Research Disclosure , Item 36544, cited above: VII. Antifog- gants and stabilizers; VIII. Absorbing and scattering materials; IX. Coating physical property modifying addenda; X. Dye image formers and modifiers; XI. Layers and layer arrangements; XII. Features applicable only to color negative; XIII. Features applicable only to color positive; XIV. Scan facilitating features; and XV. Supports.
  • the exposure and processing of photographic elements incorporating the emulsions of the invention can take any convenient conventional form, illustrated by Research Disclosure , Item 36544, cited above, XVI. Expo ⁇ sure; XVIII. Chemical development systems; XIX. Devel ⁇ opment; and XX. Desilvering, washing, rinsing and stabilizing.
  • Emulsion A Example
  • the mixture was stirred for 1 minute during which 14.15 ml of an aqueous sodium bromide solution (containing 1.46 g of sodium bromide) was added at the 50 second point of the hold. There ⁇ after, after the 1 minute of mixing, the temperature of the mixture was raised to 60°C over a period of 9 minutes. Then 16.7 ml of an aqueous solution of ammo ⁇ nium sulfate (containing 1.68 g of ammonium sulfate) were added, and the pH of the mixture was adjusted to 9.5 with aqueous sodium hydroxide (IN) .
  • aqueous sodium bromide solution containing 1.46 g of sodium bromide
  • the washed silver halide emulsion contained 3.6 mole percent iodide, based on total silver.
  • the properties of the grains of this emulsion are shown in Table I below.
  • Emulsion B (Comparison)
  • This emulsion was prepared similarly as Emulsion A, except that immediately before the intro ⁇ duction of the iodoacetic acid the pBr of the emul ⁇ sion was increased to 3.75 as follows: 19.8 ml of silver nitrate solution (containing 8.072 g silver nitrate) were added at constant flow rate over a period of 11.8 minutes. Also, during the linear ramp of silver nitrate the aqueous sodium bromide was started 8 minutes after the silver nitrate addition started, and 170.3 ml of aqueous sodium bromide solu- tion (containing 43.8 g of sodium bromide) were added using a matched ramp.
  • the washed silver halide emulsion contained 3.6 mole percent iodide, based on total silver.
  • the properties of the grains of this emulsion are shown in Table I below.
  • Emulsion Grain Size Thickness Aspect cov (microns) (microns) Ratio (percent)
  • Tabular grains accounted for substantially all of the grain projected area in Emulsion A samples.
  • the tabular grains exhibited hexagonal or triangular major faces.
  • 167 of 175 tabular grains examined exhibited well formed ⁇ 111 ⁇ major faces of a hexagonal configuration with 6 well defined, sharp corners joined by 6 linear edges. This amounts to 95.4% of the grains.
  • Dislocations were observed in the corner regions of the grains, but no dislocations were observed elsewhere in the grains, including the edge portions of the grains not included in the corner regions.
  • Examination of the tabular grains of Emul ⁇ sion B revealed that 46 out of 102 (45.1%) of the tabular grains exhibited one or more rounded edges instead of the desired geometry of corner regions joined by linear edges. Where sharp corners remained in evidence, halide conversion dislocations confined to corner regions were observed. In portions of the degraded tabular grains showing rounded edges no dislocations were detected.
  • the emulsions listed in Table I were opti- mally sensitized using two green sensitizing dyes in a weight ratio of 8.2 to 1.
  • Dye D-l anhydro-5, 5'- dichloro-9-ethyl-3,3 '-bis(3-sulfopropyl)oxacarbo- cyanine hydroxide triethylamine, was present in the larger amount
  • Dye D-2 3,9-diethyl-5-phenyl-3 ' - [N- (methylsulfonyl)carbamoylmethyl]benzothiazolo- oxacarbocyanine hydroxide, inner salt, was present in the smaller amount.
  • the sensitized emulsions were combined with a cyan-dye forming coupler, C-l, and coated on a photographic film support with a silver coverage of
  • Emulsion A The emulsion of the invention, Emulsion A, exhibited a large speed advantage. A speed difference of 30 is equal to a doubling in photographic speed. The speed of Emulsion A, representing the invention, was almost double that of the control, Emulsion B.

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Abstract

L'invention concerne une émulsion photographique sensible aux radiations, contenant un véhicule gélatineux et des grains tabulaires représentant au moins 70 % de la surface totale projetée de grains, comprenant au moins 90 % en moles de bromure et jusqu'à 12 % en moles d'iodure, par rapport à la totalité de l'argent. Cette émulsion présente des faces principales {111} formant des coins reliés par des arêtes linéaires, ainsi que des dislocations de la conversion d'halogénure limitées aux zones des coins. On peut obtenir une amélioration des performances et de la conversion d'halogénure sur des sites sélectionnés, en maintenant un pBr inférieur à 3,5 et en employant, pour la conversion d'halogénure, une source d'ion d'iodure présentant une constante de vitesse de réaction du deuxième ordre, avec le véhicule gélatineux, inférieure à 10?-3 mole-1 sec-1¿.
PCT/US1995/012522 1994-10-26 1995-10-13 Emulsions a grains tabulaires avec conversions d'halogenure sur des sites selectionnes et procedes de preparation desdites emulsions Ceased WO1996013759A2 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
JP8514580A JPH09507591A (ja) 1994-10-26 1995-10-13 選択部位ハロゲン化物転化物を有する平板状粒子乳剤およびその調製方法
DE69526202T DE69526202T2 (de) 1994-10-26 1995-10-13 Tafelkornemulsion mit Halogenidumwandlungen an ausgewählten Orten und Verfahren zu deren Herstellung
EP95936216A EP0737329B1 (fr) 1994-10-26 1995-10-13 Emulsions a grains tabulaires avec conversions d'halogenure sur des sites selectionnes et procedes de preparation desdites emulsions

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US08/329,591 US5476760A (en) 1994-10-26 1994-10-26 Photographic emulsions of enhanced sensitivity
US08/329,591 1994-10-26
US77495P 1995-06-30 1995-06-30
US60/000,774 1995-06-30

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WO1996013759A2 true WO1996013759A2 (fr) 1996-05-09
WO1996013759A3 WO1996013759A3 (fr) 1996-06-20

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JP2604246B2 (ja) * 1989-07-28 1997-04-30 富士写真フイルム株式会社 ハロゲン化銀写真感光材料およびその製造方法
JP2664277B2 (ja) * 1990-10-01 1997-10-15 富士写真フイルム株式会社 ハロゲン化銀写真感光材料
JP2664278B2 (ja) * 1990-10-15 1997-10-15 富士写真フイルム株式会社 ハロゲン化銀写真乳剤及び写真感光材料

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EP0737329B1 (fr) 2002-04-03
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EP0737329A1 (fr) 1996-10-16
WO1996013759A3 (fr) 1996-06-20

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