EP0016061B1 - Organic halogen compounds used in direct positive emulsions - Google Patents

Organic halogen compounds used in direct positive emulsions Download PDF

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Publication number
EP0016061B1
EP0016061B1 EP79900704A EP79900704A EP0016061B1 EP 0016061 B1 EP0016061 B1 EP 0016061B1 EP 79900704 A EP79900704 A EP 79900704A EP 79900704 A EP79900704 A EP 79900704A EP 0016061 B1 EP0016061 B1 EP 0016061B1
Authority
EP
European Patent Office
Prior art keywords
emulsion
organic halogen
silver halide
halogen compound
direct positive
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.)
Expired
Application number
EP79900704A
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German (de)
English (en)
French (fr)
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EP0016061A1 (en
EP0016061A4 (en
Inventor
Ronald Anthony Prados
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.)
EIDP Inc
Original Assignee
EI Du Pont de Nemours and Co
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Filing date
Publication date
Application filed by EI Du Pont de Nemours and Co filed Critical EI Du Pont de Nemours and Co
Publication of EP0016061A1 publication Critical patent/EP0016061A1/en
Publication of EP0016061A4 publication Critical patent/EP0016061A4/en
Application granted granted Critical
Publication of EP0016061B1 publication Critical patent/EP0016061B1/en
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Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
    • G03C1/00—Photosensitive materials
    • G03C1/005—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein
    • G03C1/485—Direct positive emulsions
    • G03C1/48515—Direct positive emulsions prefogged
    • G03C1/48523—Direct positive emulsions prefogged characterised by the desensitiser

Definitions

  • This invention relates to the field of photography, and more particularly to direct positive silver halide emulsion technology.
  • the present invention advances beyond the prior art and is directed to a process requiring the addition of certain organic halogen compounds to direct positive silver halide photographic elements, characterized in that the addition step is followed by a digestion step.
  • the term "digestion” is used here to denote a process in which a direct positive silver halide emulsion containing one of the aforesaid organic halogen compounds is heated for a time and at a temperature sufficient to permit the organic halogen compound to selectively oxidize silver fog centers in the emulsion. The result is an increase in the photosensitivity of the emulsion, with no adverse effect on stability.
  • a direct positive silver halide photographic emulsion of superior speed and stability is produced by a process which consists of the steps of (1) preparing a silver halide precipitate in a colloid binder, (2) fogging the resulting emulsion, (3) adding an organic halogen compound, and (4) coating the emulsion on a support, characterized in that, the emulsion is digested after step (3) and before step (4) to promote thermal reaction of the organic halogen compound with the fog centers and in that the organic halogen compound is a chlorine- or bromine-containing compound which is a weak oxidizing agent capable of oxidizing fog centers to produce an emulsion of superior speed. During the reaction the organic halogen compound is reduced and the fog centers are partially oxidized.
  • a direct positive silver halide photographic emulsion of superior speed and stability is produced in accordance with that feature by a process which comprises the steps of (1) preparing a silver halide precipitate in a colloid binder, (2) fogging the resulting emulsion, (3) adding an organic halogen compound, and (4) coating the emulsion on a support, characterized in that the organic halogen compound is 2 - tribromomethylquinoline, a,a,a',a' - tetrabromoxylene, 2 - tribromomethylquinoxaline, 2,2,3,4 - tetrachloronaphth - 1 - one or 2 - dibromomethylquinoline.
  • the present invention provides the means to increase the sensitometric speed response of direct positive silver halide photosensitive elements without undue sacrifice of gradient, top density, and resolution, and without the need for formulation changes.
  • Speed can be increased by a factor of 5 without affecting Dmax or contrast.
  • the degree of speed increase is surprising in comparison to other means of increasing sensitivity, which include: alteration of silver halide grain growth, metal doping of the grains, and the use of new sensitizing and desensitizing dye structures and dye combinations.
  • organic halogen compound the organic molecule to which the bromine or chlorine is attached must serve as a suitable carrier and not allow premature discharge, decomposition, or volatilization since this would negate the desired enhancement of photosensitivity.
  • new control or environmental protection facilities are often necessitated by the use of compounds of high volatility, but the compounds of the present invention have no such disadvantage.
  • these organic halogen compounds which are characterized as weak oxidizing agents, derive their utility from being reacted in the emulsion during the thermal treatment, i.e., digestion, whereby the weak oxidant is reduced and therefore no further changes in properties occur upon aging.
  • Particularly effective compounds of the instant invention are the following: 2 - chloro - 4 - nitrobenzyl chloride, 2,2,3,4 - tetrachloronaphth - 1 - one, 1,4 - bis(trichloromethyl) - benzene, tribromoacetic acid, tetrachlor - orthobenzoquinone, 1,3 - dibromo - 5,5 - dimethyl hydantoin, 1 - chlorobenzotriazole, a - bromo - p - toluic acid, 2 - trichloromethyl - 4(3H) quinazolinone, p - bromoacetophenone, m - nitrobenzyl chloride, 2 - tribromomethylquinaldine, 2,6 - dichlorobenzonitrile, 2
  • the increase in direct positive photosensitivity provided by the present invention results from the simple step of adding and digesting the organic halogen compound in the emulsion.
  • this technique it is possible to use this technique to obtain desirable speed increase without the necessity of further modification of an existing direct positive emulsion formulation.
  • other techniques for speed increase usually require that other changes and modifications accompany the means for speed increase.
  • to provide a new grain might require alteration of the steps of ripening the emulsion; of washing, sensitizing and stabilizing the emulsion; using auxiliary additives, etc. to allow coating and drying of the emulsion.
  • a new or improved dye may not be compatible with a sensitization technique previously used.
  • the present invention is operative with silver halide grains produced by both single jet and double jet precipitation techniques, to yield heterodisperse and monodisperse grain size distribution.
  • metal ions may be introduced to modify the photographic response and/or to act as fogging agents.
  • Nonmetals, and compounds thereof may also be used to fog or precondition the grains during physical ripening, or, as an alternate fogging mechanism, the grains may be exposed to actinic radiation.
  • the term "core-shell" grain has come to apply to such layered grains.
  • both the type of fogging agent to be used and the degree of fogging are dependent on concentration, pH, pAg, temperature, and duration of the treatment. Both surface and internal fog centers are recognized as functional for direct positive emulsions.
  • Suitable metals for fogging include gold, tin, lead, palladium, and iridium.
  • Suitable nonmetallic compounds include amine borane, hydrazine, thiourea dioxide, formaldehyde, and allyl thiourea.
  • the organic halogen compound may be added to the emulsion, and the oxidation-reduction reaction is carried out by holding the system at an elevated temperature to allow it to proceed towards completion.
  • the organic halogen compounds of this invention will function in the presence of dyes known to be useful in direct positive emulsions, including those disclosed, for example, in U.S. 3,615,643; U.S. 3,583,870; U.S. 3,867,149; U.S. 3,898,216; and U.S. 3,747,986.
  • These dyes are useful as desensitizers which increase the response of direct positive silver halide emulsions. While useful with these desensitizing dyes, the present invention also functions in their absence.
  • Specially sensitizing dyes that are not electron accepting may also be present in the emulsion such as single and complex cyanines, merocyanines, styryls, and hemicyanines.
  • the silver halide constituent of the direct positive silver halide emulsions described herein may consist of pure or mixed silver chloride, bromide, or iodide, and the grains may be regular or irregular in shape, e.g. cubic, octahedral and rhombohedral.
  • the novel emulsions described in GB-A-2,038,792, "Novel Silver Halide Crystals with Two Surface Types", are also useful in the practice of the present invention.
  • speed-increasing compounds such as polyalkylene glycols; surface active agents which are useful as coating aids; antifoggants; and stabilizers, including indazoles, imidazoles, azaindenes, mercury, and polyhydroxy benzene compounds.
  • useful ingredients for these direct positive elements include hardeners, antistatics, matting agents, plasticizers, brighteners, and natural and synthetic wetting agents. All these useful ingredients may be combined to yield formulations capable of being coated on suitable supports such as cellulose nitrate film, cellulose ester film, polyvinyl acetal film, polystyrene film, poly(ethylene terephthalate) film, and related films or resinous materials, as well as glass, paper, metal and the like.
  • a rhodium-doped monodisperse cubic Ag(I)Br emulsion containing 1.0% iodide and 0.01% rhodium was prepared by the balanced double jet precipitation technique, maintaining a pAg of 8.2. After completion of physical ripening, the emulsion was coagulated with polyvinyl alcohol o-sulfobenzaldehyde acetal and the excess halide salts removed by decanting. The washed emulsion was redispersed in gelatin; the pH was adjusted to 7.5, and the pAg to 8.0.
  • the emulsion was fogged by adding, per mole of silver halide, 2.4 ⁇ 10 -7 mole of cesium thiodecaborane and 3.1 ⁇ 10 -6 mole of gold chloride stabilized with hydrochloric acid. After digesting at 72°C for 2 hours the emulsion was cooled to 35°C and cetyl betaine was added as a coating aid.
  • the emulsion was split into portions and additions made as in Table 1 below.
  • the samples were coated on photographic grade polyester base at 35 mg/dm 2 silver bromide.
  • the samples with dye were exposed at 10 -3 sec. with a 19 line compensator on an EGG sensitiometer through a V2 wedge.
  • the nondyed samples were exposed using a tunsten lamp (750 watts) operated at 35 volts for 15 sec.
  • the samples were developed in a standard metol-hydroquinone developer for one minute, dipped in an acetic acid stop for 30 sec., fixed in a standard thiosulfate fixer for one minute, and dried.
  • the samples showed the sensitometric response reported in Table 2 where the speed was measured at 0.1 optical density over Dmin and the gradient is measured over the straight line curve portion.
  • Table 2 shows that similar speed increases can be obtained with and without the presence of the direct positive dye. The results also show that the effects of dye and halogen-donating compound are additive.
  • An emulsion prepared as in Example 1 was split into three equal portions.
  • To Part VIII 1.1 g of 2 - dibromomethylquinoline/mole of silver halide was added.
  • To Part IX 0.12 g of 2 - tribromomethylquinoline/mole silver halide were added.
  • Part X was kept as a control.
  • the direct positive dye was added and samples coated at a coating weight of 40 mg AgBr/dm 2 . The samples were exposed for one minute through a ⁇ 2 wedge in a contact mode using a Tungsten source at maximum output with a 0.6 neutral density filter.
  • Emulsion samples were prepared as in Example 1 and split into three portions. To sample XI was added 0.122 mg of 2 - tribromomethylquinoxaline/mole of silver halide, to sample XII 0.122 mg of 2 - tribromomethylquinoline/mole silver halide, and sample XIII was the control. The samples were coated without the direct positive dyes and processed as in Example 1. The results are reported in Table 5, and they show that under similar processing conditions the 2 - tribromomethylquinoline and 2 - tribromo- methyl - quinoxaline compounds behave identically.
  • a monodisperse cubic trihalide emulsion (Br-90/Cl-9.5/1-0.5) was prepared by a balanced double jet precipitation as described in Example 1 of GB-A-2 038 792. Unlike the iodobromide emulsion of Example 1, no rhodium was included during precipitation. The emulsion was washed and redispersed as in Example 1. The emulsion was fogged by adding thereto 7.3x10- 8 moles of cesium thiadecaborane and 1.6x10- 4 mole of gold chloride, stabilized with HCI, per mole of silver halide, followed by digesting at 72°C for 100 minutes.
  • Example 8 gives comparative results obtained with the splits of this emulsion with and without the digestion step of the invention. Samples were coated at 35 mg/dm 2 and exposed and processed as in Example 1. When these same coatings were tested after one month normal aging it was determined that only the control XXV and the two digested emulsions (XXVIII and XXVIX) showed speed values within 10% of those in Table 8. Since a 10% variation is within experimental error, this demonstrates that the digested samples were remarkably storage-stable.
  • Emulsion splits were prepared and fogged as in Example 7.
  • Table 9 gives comparative results obtained when varied amounts of an organic halogen compound were added with and without the digestion step. Unlike other organic halogen compounds which show an effect on sensitivity even without digestion, this compound requires a longer digestion period than more active halogen oxidizing agents used in previous examples.
  • Example 10 An emulsion was prepared as in Example 1 except that the fogging reaction was carried out with 2.9x10-' mole of cesium thiodecaborane and 4.6x10-6 mole of gold chloride per mole of silver halide. Table 10 gives comparative results obtained when the same amount of an organic halogen compound was digested for different times in comparison to a control containing no addition.
  • Temperatures of from 40°C to 80°C are useful for the digestion reaction without adversely affecting the emulsion. Times as short as 5 minutes and up to as long as several hours can be used in order to accommodate the reactivity of the particular organic halogen compound being used to react with the fogged centers.
  • the effective amount of organic halogen compound may vary from as little as 0.01 g to as much as 1.00 g. It has been found convenient to operate with temperature of from 45°C to 65°C for periods of from 10 to 120 minutes using from 0.015 g to 0.50 g of the organic halogen compounds.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Non-Silver Salt Photosensitive Materials And Non-Silver Salt Photography (AREA)
EP79900704A 1978-06-02 1980-01-14 Organic halogen compounds used in direct positive emulsions Expired EP0016061B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US91201678A 1978-06-02 1978-06-02
US912016 1978-06-02

Publications (3)

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EP0016061A1 EP0016061A1 (en) 1980-10-01
EP0016061A4 EP0016061A4 (en) 1981-08-27
EP0016061B1 true EP0016061B1 (en) 1985-04-10

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EP79900704A Expired EP0016061B1 (en) 1978-06-02 1980-01-14 Organic halogen compounds used in direct positive emulsions

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EP (1) EP0016061B1 (enrdf_load_stackoverflow)
JP (1) JPS6161372B2 (enrdf_load_stackoverflow)
BE (1) BE876734A (enrdf_load_stackoverflow)
CA (1) CA1142788A (enrdf_load_stackoverflow)
DE (1) DE2967425D1 (enrdf_load_stackoverflow)
WO (1) WO1980000040A1 (enrdf_load_stackoverflow)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4845011A (en) * 1987-10-23 1989-07-04 Hoechst Celanese Corporation Visible light photoinitiation compositions
US4945027A (en) * 1987-10-23 1990-07-31 Hoechst Celanese Corporation 1,4 or 9,10 dimethoxyanthracene triggers for 2-tri(chloro or bromo)methyl-4(1H)-quinazolimone polymerization initiators
JPH06100795B2 (ja) * 1988-05-13 1994-12-12 富士写真フイルム株式会社 ハロゲン化銀写真感光材料
JPH0271172U (enrdf_load_stackoverflow) * 1988-11-16 1990-05-30
GB9221383D0 (en) * 1992-10-12 1992-11-25 Minnesota Mining & Mfg Photothermographic imaging materials and antifoggants therefor

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1186790A (en) * 1966-11-16 1970-04-02 Gaf Corp Improvements in or relating to Gelatin Coating Compositions

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH378283A (de) * 1959-10-15 1964-07-31 Agfa Ag Verfahren zur Herstellung von farbigen photographischen Bildern auf Textilmaterial
US3495987A (en) * 1965-09-03 1970-02-17 Du Pont Photopolymerizable products
US3510348A (en) * 1966-03-11 1970-05-05 Eastman Kodak Co Direct positive recording film
US3637387A (en) * 1967-10-24 1972-01-25 Agfa Gevaert Nv Direct positive emulsion containing a halide releasing compound developed in the presence of an unsubstituted hydrazine
US3632340A (en) * 1968-09-09 1972-01-04 Eastman Kodak Co Cored direct positive silver halide emulsion developed with polyhydroxybenzene
BE757145A (nl) * 1969-10-09 1971-04-07 Agfa Gevaert Nv Fotografische opnametechniek
GB1427525A (en) * 1972-07-13 1976-03-10 Agfa Gevaert Directpositive silver halide emulsions

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1186790A (en) * 1966-11-16 1970-04-02 Gaf Corp Improvements in or relating to Gelatin Coating Compositions

Also Published As

Publication number Publication date
BE876734A (fr) 1979-12-03
CA1142788A (en) 1983-03-15
EP0016061A1 (en) 1980-10-01
JPS6161372B2 (enrdf_load_stackoverflow) 1986-12-25
WO1980000040A1 (en) 1980-01-10
DE2967425D1 (en) 1985-05-15
EP0016061A4 (en) 1981-08-27
JPS55500380A (enrdf_load_stackoverflow) 1980-06-26

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