US3708298A - Method of producing direct positive images with photographic silver halide material containing compound releasing iodide ions - Google Patents

Method of producing direct positive images with photographic silver halide material containing compound releasing iodide ions Download PDF

Info

Publication number
US3708298A
US3708298A US00111705A US3708298DA US3708298A US 3708298 A US3708298 A US 3708298A US 00111705 A US00111705 A US 00111705A US 3708298D A US3708298D A US 3708298DA US 3708298 A US3708298 A US 3708298A
Authority
US
United States
Prior art keywords
silver halide
emulsion
light
direct positive
silver
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 - Lifetime
Application number
US00111705A
Other languages
English (en)
Inventor
G Vanreusel
Pee P Van
Laet J De
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.)
Agfa Gevaert NV
Agfa Gevaert AG
Original Assignee
Agfa Gevaert AG
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Agfa Gevaert AG filed Critical Agfa Gevaert AG
Application granted granted Critical
Publication of US3708298A publication Critical patent/US3708298A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

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
    • G03C7/00—Multicolour photographic processes or agents therefor; Regeneration of such processing agents; Photosensitive materials for multicolour processes
    • G03C7/30—Colour processes using colour-coupling substances; Materials therefor; Preparing or processing such materials
    • G03C7/3022—Materials with specific emulsion characteristics, e.g. thickness of the layers, silver content, shape of AgX 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
    • G03C1/485—Direct positive emulsions
    • G03C1/48538—Direct positive emulsions non-prefogged, i.e. fogged after imagewise exposure
    • 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
    • G03C1/48592—Positive image obtained by various effects other than photohole bleaching or internal image desensitisation, e.g. Sabatier, Clayden effect

Definitions

  • the present invention relates to a novel method of producing photographic direct positive images and more particularly to a simple method according to which direct positive images of good quality are produced rapidly.
  • German patent specification 749,864 a method is described of producing a photographic direct positive image that comprises the steps of exposing a silver halide emulsion layer to an object or image, predeveloping the thus exposed layer for a considerably long time, subjecting it to an overall exposure with actinic light of low intensity and finally developing the said emulsion layer to cause a direct positive image to be formed.
  • the said predeveloping occurs preferably in a fine grain developer or fiat-working developer and the said developing in an energetic developer.
  • the silver halide emulsion layer for use in the process of said German patent specification must be such that its negative image sensitometric curve shows a maximum density that does not exceed the value 0.5.
  • a method is described of producing a photographic direct positive image that comprises the steps of exposing to an object or image a light-sensitive silver halide emulsion layer, treating said emulsion layer to render it capable of forming a surface latent image and then subjecting it to a uniform exposure of sufiicient intensity and time to cause a direct positive 3,708,298 Patented Jan. 2, 1973 'ice image to develop by treating it in a developer that will develop the surface latent image but will not or only slightly develop the first formed internal latent image.
  • the silver halide emulsion layer used must be of the type in which the latent image is formed mostly or entirely inside the grains.
  • the light-sensitive silver halide emulsion layer that has been exposed to an object or image may also, without development of the latent image so formed to a visible image be dipped in a photographic developing solution, which is capable of developing a surface latent image, but is capable of developing the latent image formed by said exposure only slightly, if at all, whereupon the emulsion layer is subjected to a uniform exposure of sufiicient intensity and time to cause a direct positive image to be developed when the treatment is continued in the same or another surface developer.
  • a light-sensitive material which comprises a layer of a silver halide emulsion of the type that forms a latent image predominantly in the inner part of the silver halide grains;
  • the material is generally fixed, e.g. in a usual fixing solution such as a thiosulphate solution and washed, whereupon the material may be dried or glazed.
  • a usual fixing solution such as a thiosulphate solution
  • the present invention provides a method of producing direct positive images of good quality in a rapid and simple way. This method is particularly suitable for producing continuous tone direct positive images but it is also appropriate for reproducing line originals.
  • the light-sensitive material of use according to the present invention generally comprises a support, for instance a paper support or a hydrophobic film support that is either transparent or not, to which the light-sensitive silver halide emulsion layer is applied, if need be by means of an appropriate subbing layer.
  • a support for instance a paper support or a hydrophobic film support that is either transparent or not, to which the light-sensitive silver halide emulsion layer is applied, if need be by means of an appropriate subbing layer.
  • the silver halide emulsion used in carrying out the method of this invention is of the type in which the latent image is formed predominantly in the inner part of the silver halide grains. This means an emulsion only few or none of the exposed grains of which are developable to silver by a developing solution which cannot act as a developer for latent image inside the grains, i.e. a socalled surface" developer such as the following developing solution:
  • the silver halide emulsions used according to the invention are generally not or only slightly chemically ripened silver halide emulsions, since the extent of the surface latent image forming ability increases with the degree of chemical ripening.
  • Silver chlorobromide emulsions comprising at least 20 mole percent of silver bromide and pure silver bromide emulsions have proved to be specially suitable for the purpose of the invention. These emulsions may contain up to 5 mole percent of silver iodide relative to the total amount of silver halide. Washed as well as unwashed silver halide emulsions may be used.
  • the silver halide emulsions for use in the present process are generally gelatino silver halide emulsions.
  • the gelatin may at least partly be replaced e.g. by another protein, a hydrophilic not proteinaceous colloid, e.g. a polyvinylpyrrolidone or a synthetic polymer applied from an aqueous dispersion, i.e. a latex, e.g. a polyethyl acrylate latex.
  • a latex e.g. a polyethyl acrylate latex.
  • the presence of such other binders often has also a favourable photographic effect on the formation of the direct positive image.
  • the addition of the polyvinylpyrrolidone and of said polyethyl acrylate latex in most cases increases the maximum density of the direct positive image.
  • the light-sensitive silver halide emulsions used according to the invention may be prepared according to any technique known in the art.
  • a method according to which emulsions are prepared, which have proved to be particularly suitable for the purpose of the invention, is the so-called conversion method.
  • a more soluble silver halide is converted in a less soluble silver halide, e.g., a silver chloride emulsion is converted in the presence of water-soluble bromide and occasionally iodide, the amounts of which are adapted in view of the final composition aimed at, into a silver chlorobromide or a silver bromide emulsion which may occasionally comprise small amounts of silver iodide.
  • This conversion is carried out preferably very slowly by several consecutive steps.
  • a compound releasing iodide ions in an aqueous medium is incorporated subsequent to precipitation of the silver halide.
  • this compound causes the favorable effect of the invention, viz the production of a direct positive image showing a high maximum density.
  • the compound releasing iodide ions is added to the liquid silver halide emulsion after the silver halide grains have been precipitated.
  • the compound releasing iodide ions may not be added earlier than after the said conversion has been carried out.
  • the compound releasing iodide ions may also be incorporated within the emulsion layer by diffusion from or through another layer, which is in water-permeable relationship with the emulsion layer. This diffusion occurs automatically and immediately when the silver halide emulsion is applied to a water-permeable layer containing the compound releasing iodide ions or when an aqueous coating liquid containing the compound releasing iodide ions is applied to the silver halide emulsion layer or to a water-permeable layer present on top of the emulsion layer.
  • the compound releasing iodide ions must be present in the silver halide emulsion layer before the aqueous energetic surface developer is applied to the imagewise exposed light-sensitive material.
  • the favorable eifect of the method of the invention cannot be obtained if the compound releasing iodide ions is present in the developer itself. Proceeding in this way is outside the scope of this invention.
  • the compound releasing iodide ions is generally incorporated within the silver halide emulsion layer at a concentration within the range of about 0.01-20 grams per mole of silver halide and preferably in an amount of between 0.1 and 5 grams per mole of silver halide.
  • Suitable compounds releasing iodide ions are watersoluble iodides, inorganic as Well as organic iodides, organic compounds with labile iodine atom, onium chloroiodates and molecular iodine and its addition products, e.g. with polyvinylpyrrolidone, with polyoxyalkylenes and their derivatives or with quaternary ammonium compounds.
  • Suitable inorganic iodides are for instance, calcium iodide, ammonium iodide, lithium iodide, magnesium iodide, potassium iodide, sodium iodide, barium iodide, cadmium iodide, and zinc iodide.
  • Suitable organic iodides are for instance the iodides having the following structural formulae:
  • Organic compounds with labile iodine atom which have proved to be suitable for use according to the invention are, e.g., mono-iodoacetic acid and 4-iod0-butane sulphonic acid potassium salt.
  • onium chloroiodates there may be referred to Belgian patent specification No. 515,895; examples of suitable onium chloroiodates are among others more particularly:
  • the compound releasing bromide ions is mostly incorporated within the silver halide emulsion layer at the same concentration range given above for the compounds releasing iodide ions.
  • Suitable compounds releasing bromide ions are among other inorganic and organic bromides such as ammonium bromide, lithium bromide, sodium bromide, potassium bromide, magnesium bromide, calcium bromide, barium bromide, cadmium bromide and zinc bromide as inorganic bromides and tetraethyl ammonium bromide and ethyl pyridinium bromide as organic bromides.
  • Organic compounds with labile bromine atom such as monobromoacetic acid are also suitable for being used in the present process as compounds setting free bromide ions.
  • a first step for the preparation of the direct positive image the light-sensitive material is image-wise exposed to the original to be reproduced.
  • This exposure can be either a high-intensity exposure such as flash exposure or a normal-intensity exposure such as daylight exposure as well as a low-intensity exposure such as an exposure by means of a printer or an exposure of still lower intensity, the exposure-time being dependent on the sensitivity of the light-sensitive material for the direct positive image formation which sensitivity according to the present invention may be a camera speed as Well as a lower sensitivity.
  • the image-wise exposed light-sensitive material is treated with an aqueous energetic surface developing liquid.
  • This treatment may be carried out according to any technique known in the art, e.g. by soaking or by wetting only one side of the lightsensitive material, e.g. by means of a lick roller, by spreading a paste, e.g. contained in a pod, or by spraying.
  • the developing liquid, also called developer, of use in the process of the invention must be a surface developer, i.e. a developer that contains no or at least no effective amount of solvents for silver halide.
  • solvents for silver halide there are meant particularly strong solvents for silver halide such as water-soluble thiocyanates, thiosulphates, ammonia, etc. Indeed, compounds that may be considered to be but very weak solvents for silver halide, such as sodium sulphite in case the silver halide is silver bromide, silver chlorobromide, or silver bromoiodide, may be present in the developer.
  • the developer has to be an energetic developer.
  • the high energy required can be realized by taking, e.g. one or more of the following measures:
  • suitable developing substances are among others the combination of 1- phenyl-3-pyrazolidinone with hydroquinone and the combination of monomethyl-p-aminophenol sulphate with hydroquinone. In general there may be said that the more energetic the developer is the better the result obtained will be.
  • the developing agents may also be incorporated partially or even completely into the light-sensitive material. This incorporation may be accomplished during the preparation state of the material or later on by means of a processing liquid, with which the light-sensitive material is wetted prior to the development of the direct positive image. In doing so the energetic surface developer can be reduced to a mere alkaline liquid substantially free from developing agents.
  • a processing liquid with which the light-sensitive material is wetted prior to the development of the direct positive image.
  • the energetic surface developer can be reduced to a mere alkaline liquid substantially free from developing agents.
  • Such an alkaline aqueous liquid often called activator, offers the advantage of having a longer activity, i.e. of being less rapidly exhausted.
  • the developer (occasionally activator) may be supplied in an amount, which suflices for the treatment of exactly one foil of light-sensitive material.
  • a bath of this type offers the advantage that ageing and contamination of the bath composition are avoided.
  • the image-wise exposed light-sensitive layer is present in the developer or is moistened therewith in some way the said light-sensitive material is overall and generally uniformly exposed to actinic light of low intensity, i.e. of an intensity which is lower than a normal daylight intensity.
  • This exposure may begin simultaneously with the treatment of the light-sensitive material with developer but occurs favourably a little later for instance from 5 to 30 seconds later.
  • the duration of the secondary or overall exposure is not very critical and may amount from seconds to many minutes according to the nature of the light-sensitive material, the composition and the temperature of the developer, the intensity of the lightsource employed, etc. In many cases the overall exposure lasts till the direct positive image is completely developed.
  • the density of the direct positive image can be made more intense or reduced locally during the second or overall exposure by the well known technique of burning in and dodging. In general the total development of the direct positive image does not take much time and in most cases may be carried out in from 1 to 5 minutes.
  • the uniformity of the said overall exposure to actinic light of low intensity is mostly achieved by interposing between the light-source and the light-sensitive material to be exposed a light-diffusing member that transmits at least part of the light rays of the spectral region for which the lightsensitive material is sensitive.
  • the required low intensity of the light rays, which reach the light-sensitive material can be obtained by adapting the light-source and/or the light-diffusing member.
  • the direct positive images obtained according to the present invention show very high maximum densities and have sufiiciently low minimum densities.
  • This minimum density can still be lowered by incorporating a fog-inhibiting compound that inhibits fogging during the development stage and that belongs to the class of the heterocyclic thione compounds, within the light-sensitive silver halide emulsion layer.
  • the fog-inhibiting compound is incorporated within the silver halide emulsion layer by adding it to the liquid silver halide emulsion, generally just before coating.
  • the fog-inhibiting compound may also be incorporated within the emulsion layer by difiusion from or through another layer, which is in water-permeable relationship with the emulsion layer.
  • the fog-inhibiting compounds give rise to a lowering of the minimum density of the direct positive image already when present in only small amounts. They are very eflicient when applied in the common fog-inhibiting amounts, i.e. in amounts of up to 0.1 mole per moles of silver halide. The best results, i.e. the most clear minimum densities are however attained when using the fog-inhibiting compounds in amounts larger than the common fog-inhibiting amounts, i.e. in amounts of at least 0.1 mole per 100 moles of silver halide. These large amounts of fog-inhibiting compound normally are not applied to the light-sensitive materials since with such amounts the light-sensitive material would be too strongly desensitized. What is surprising now is that in the process of the present invention, these large amounts of fog-inhibiting compound do not lower the direct positive image sensitivity of the lightsensitive material but in most cases even enhance it and also do not prevent the formation of a direct positive image with good maximum density.
  • Suitable fog-inhibiting compounds belonging to the class of the heterocyclic thione compounds are:
  • any reference in the description and in the claims to fog-inhibiting compounds of the class of the heterocyclic thione compounds is intended to refer also to the tautomeric structures of said compounds and to salts of said compounds or occasionally of said tautomeric structures. Mixtures of two or more fog-inhibiting compounds may also be employed.
  • the maximum or minimum density of the direct positive image can still be improved and the characteristics of the light-sensitive material can be altered by using all kinds of ingredients which are generally known in the art of emul sion preparation and some of which will be set out specifically hereinafter.
  • ingredients are preferably incorporated into the light-sensitive material itself, in effective contact with the silver halide emulsion layer and favourably in the latter layer itself.
  • Many of these ingredients may be incorporated into the energetic surface developer with the same favourable result. Combinations of two or more of said ingredients, of course, may also be used.
  • binders for at least partially replacing gelatin as a binder for the silver halide grains may be mentioned some binders for at least partially replacing gelatin as a binder for the silver halide grains and referred to already above in the description, further optical sensitizers and moistening agents such as polyalkylene glycols; i.a. polyethyleneglycols, sulphonated fatty acids, saponine and the like.
  • optical sensitizers and of polyalkylene glycols in the silver halide emulsion layer in most cases has a favourable effect on the maximum density of the direct positive image.
  • Still further ingredients are mentioned later on in the description.
  • the process according to the invention is not restricted to black and white photography; it may also be applied for the preparation of direct positive colour images by carrying out the development in an energetic colour developer in the presence of a colour coupler and by bleaching away the silver developed.
  • the light-sensitive material may be a multilayer colour material each layer of which absorbs a particular part of the spectrum and for which layers appropriate colour couplers are provided.
  • many colour developing compounds and colour couplers exert an advantageous effect on the mechanism of the direct positive image production itself in that they contribute to a higher maximum and/or a lower minimum density.
  • a negative image is formed in the silver halide emulsion layer in addition to the direct positive image, just as is the case with the Sabattier effect.
  • the positive and negative image overlap with each other whereas according to our invention there is a clear separation between the direct positive and the negative image that forms in a lower sensitivity range.
  • This separation is clearest when the image-wise exposure is a high-intensity exposure, e.g. a flash exposure and is less clear accordingly as the intensity of the image-wise exposure is lower. Nevertheless, excellent results can still be attained with a normal daylight exposure and even with an exposure of still lower intensity, for instance an exposure by means of a printer.
  • a negative image in the low sensitivity range can also be obtained by developing this material after image-wise exposurein a surface developer without subjecting it to a second or overall exposure.
  • a gelatino silver bromide emulsion that forms a latent image predominantly in the inner part of the silver halide grains is prepared through conversion of a silver chloride emulsion by very slowly adding to said emulsion whilst stirring a 35% aqueous potassium bromide solution in an amount that is 70% higher than the amount theoretically necessary for converting all the silver chloride.
  • the emulsion is then kept for 1 hour at 60 C.
  • the emulsion After the emulsion has been chilled and allowed to gel for 6 hours the emulsion is noodled.
  • the noodles are washed for 1 hour with water (10 litres of water per minute). By heating the washed noodles a liquid silver bromide emulsion is obtained containing 50 g. of gelatin and 0.4 mole of silver bromide per kg.
  • potassium iodide is added as follows: to a first part of the emulsion 6 cc. of a 5% aqueous potassium iodide solution are added per kg., to a second part 10 cc. of such solution are added per kg. and to a third part 20 cc. of such solution are added per kg.
  • Each of the light-sensitive emulsions obtained is coated, practically immediately after the addition of the potassium iodide solution, on a baryta-coated paper support of g./sq. m. in such a way that an amount of silver halide equivalent to 4 g. of silver nitrate is present per sq. m. of light-sensitive material.
  • the emulsion layer of each of the materials is overcoated with a conventional hardened gelatin antistress layer.
  • the three silver halide materials obtained are further treated in a completely identical way.
  • Each material is image-wise exposed for l/ioyoor) sec. through a stepwedge by means of a flash exposure of 130 lux sec. Then each material is developed for 4 min. at 20 C. in a surface developer of the following composition:
  • the lightsensitive material is overall exposed for the remaining time of the development through a grey filter having a density of 2.7 means of a IS-Watt lamp placed at a distance of 70 cm. from the light-sensitive material.
  • a grey filter having a density of 2.7 means of a IS-Watt lamp placed at a distance of 70 cm. from the light-sensitive material.
  • Each of the light-sensitive materials is then fixed, rinsed and dried in the conventional way.
  • a direct positive image of the original is obtained in each of the three materials.
  • the three images all have a low minimum density and a high maximum density which is the higher the more potassium iodide has been incorporated into the light-sensitive material.
  • the direct positive images obtained according to the method of the invention as described in this example show a much higher maximum density and practically the same minimum density.
  • a gelatino silver bromide emulsion that forms a latent image predominantly in the inner part of the silver halide grains is prepared through conversion of a silver chlorobromide emulsion (10 mole percent of bromide) by very slowly adding to said emulsion whilst stirring a 35% aqueous potassium bromide solution in an amount that is 90% higher than the amount theoretically necessary for converting all the silver chloride.
  • the emulsion is then kept for 1 hour at 60 C. After the emulsion has been chilled and allowed to gel for 6 hours the emulsion is noodled. The noodles are washed for 1 hour with water (10 litres of water per minute). By heating the Washed noodles a liquid silver bromide emulsion is obtained containing 50 g. of gelatin and 0.4 mole of silver bromide per kg.
  • an appropriate colour coupler for yellow is added in a concentration as commonly applied as well as potassium iodide in the following amounts: to a first part of emulsion 2.5 cc. of percent aqueous potassium iodide solution are added per kg of emulsion and to a second part 5 cc. of such solution are added per kg. of emulsion.
  • each of the lightsensitive emulsions is coated on a 'baryta-coated paper support of 130 g./sq. m. in such a way that an amount of silver halide equivalent to 4 g. of silver nitrate is present per sq. m. of light-sensitive material.
  • the emulsion layer of each of the materials is overcoated with a conventional hardened gelatin antistress layer.
  • the two silver halide materials obtained are further treated in a completely identical way. Each material is image-wise exposed for sec. through a step-wedge by means of a flash exposure of 130 lux sec. Then each material is developed for 2 min. at 26 C. in a developer of the following composition:
  • each material is treated in a stop bath, bleached, fixed and rinsed with water as is the case with conventional photographic colour material.
  • a yellow positive image of the step-wedge is obtained in each of the two materials. These two images have a good minimum density and a high maximum density which is the higher the more potassium iodide has been incorporated into the light-sensitive material. As compared with a direct positive image obtained in the same manner but with a light-sensitive material in which no potassium iodide had been incorporated, the direct positive images obtained according to the method of the invention as described in this example show a much higher maximum density and practically the same minimum density.
  • Example 2 is repeated as far as the light-sensitive material, in which the highest amount of potassium iodide has been incorporated is concerned. However, immediately after havingincorporated said potassium iodide and before coating a 5% solution in ethanol of l-(o-methoxyphenyl)-2-tetrazoline-5-thione is also added to the silver halide emulsion in an amount of 2.5 cc. per mole silver bromide, which is an amount of fog-inhibiting compound as commonly employed.
  • the direct positive image obtained has a minimum density lower than that obtained in the corresponding material of Example 2 where no fog-inhibiting compound has been incorporated into the light-sensitive material- Its maximum density has practically not been changed as compared with the material comprising no fog-inhibiting compound.
  • Example 1 is repeated but now the liquid emulsion is not divided into different parts to which potassium iodide is added in different amounts.
  • 10 cc. of a 5% aqueous solution of potassium iodide and 10 cc. of a 5% solution in ethanol of 1-(o-methoxyphenyl)-2- tetrazoline-S-thione are added to the undivided liquid silver halide emulsion per kg.
  • the maximum and minimum densities of the direct positive image obtained are given in Table I (Test A).
  • Test B Test A is repeated with the difference however that at the moment of the addition of the potassium iodide and fog-inhibiting compound 5 cc. of a 3 N aqueous solution of cadmium bromide are also added per kg. of liquid silver halide emulsion.
  • the maximum and minimum density of the direct positive image obtained are given in Table I (Test B).
  • Test C Test B is repeated with the difference however, that at the moment of the addition of the potassium iodide, foginhibiting compound and cadmium bromide 50' cc. of a 20% aqueous solution of poly(N-vinyl pyrrolidone) (mole weight: about 40.000) are also added per kg. of liquid silver halide emulsion.
  • the maximum and minimum density of the direct positive image obtained are given in Table I (Test C).
  • Test D Test C is repeated with the difierence however that no cadmium bromide is added and that instead of 10 cc. of a 5% aqueous solution of potassium iodide, 5 cc. of a 50% aqueous solution of potassium iodide are added per kg. of emulsion.
  • the maximum and minimum density of the direct positive image obtained are given in Table I (Test D).
  • Test E is repeated with the difference however that at the moment of the addition of the potassium iodide and other substances mentioned also 5 cc. of a 3 N aqueous solution of cadmium bromide are added per kg. of liquid silver halide emulsion.
  • the maximum and minimum density of the direct positive image obtained are given in Table II (Test F).
  • Test G Test H Test F is repeated with the difference however that at the moment of the addition of the potassium iodide and other substances mentioned also 50 cc. of a 20% aqueous solution of poly(N-vinyl pyrrolidone) (mole weight about 40.000) are added per kg. of liquid silver halide emulsion.
  • the maximum and minimum density of the direct positive image obtained are given in Table II (Test H).
  • a photographic multilayer colour material is prepared by coating a baryta-coated paper supported of 130 g./ sq. 111. according to the generally known procedure successively with: a panchromatically sensitized silver halide emulsion layer, an intermediate gelatin layer, an orthochromatically sensitized silver halide emulsion layer, once again an intermediate gelatin layer, a yellow filter layer, a blue sensitive silver halide emulsion layer and a conventional hardened gelatin antistress layer.
  • the various emulsion layers are coated pro rata of /1000 to 5/100 mole of silver halide per sq. m. of material according to the nature of the emulsion, the colour coupler used, the gradation desired, etc.
  • a gelatino silver bromide emulsion that forms a latent image predominantly in the inner part of the silver halide grains is prepared through conversion of a silver chloride emulsion by very slowly adding to said emulsion whilst stirring a 35% aqueous potassium bromide solution in an amount that is 70% higher than the amount theoretically necessary for converting all the silver chloride.
  • the emulsion is then kept for 1 hour at 60 C. After the emulsion has been chilled and allowed to gel for 6 hours the emulsion is noodled. The noodles are washed for 1 hour with water litres of water per minute). By heating the washed noodles a liquid silver bromide emulsion is obtained containing 50 g. of gelatin and 0.4 mole of silver bromide per kg.
  • the coating composition of the panchromatic emulsion layer is obtained by adding to the liquid silver bromide emulsion obtained on heating the washed noodles, in addition to the usual hardening agents and coating aids, an appropriate panchromatic sensitizer and an appropriate colour coupler for cyan both in a concentration as commonly applied as well as the following solutions the amounts of which are given per mole of silver halide:
  • the coating composition of the orthochromatic emulsion layer is obtained by adding to the liquid silver bromide emulsion obtained on heating the Washed noodles, in addition to the usual hardening agents and coating aids, an appropriate orthochromatic sensitizer and an appropriate colour coupler for magenta both in a concentration as commonly applied as well as the following solutions, the amounts of which are given per mole of silver halide:
  • the coating composition of the blue-sensitive emulsion layer is obtained by adding to the liquid silver bromide emulsion obtained on heating the Washed noodles, in addition to the usual hardening agents and coating aids, an appropriate blue-sensitizer and an appropriate colour coupler for yellow both in a concentration as commonly applied as well as the following solutions, the amounts of which are given per mole of silver halide:
  • the photographic multilayer colour material obtained is exposed to a coloured continuous tone original and then developed for 3 min. at 26 C. in a developer of the following composition:
  • the said development occurs for the first 30 sec. in the dark. During the remaining time of the development the material is overall exposed to light of low intensity but actinic for all three light-sensitive layers.
  • the material is treated in a stop bath, bleached, fixed and rinsed with water as in the case with conventional photographic colour material. A direct positive image of good quality is obtained.
  • the grey rendering can be influenced by changes in the emulsion composition of the various emulsion layers but also by varying the light of the image-wise exposure and/ or of the low-intensity overall exposure by means of filters.
  • EXAMPLE 7 A gelatino silver bromide emulsion that forms a latent image predominantly in the inner part of the silver halide grains is prepared through conversion of a silver chloride emulsion by very slowly adding to said emulsion whilst stirring a 35% aqueous potassium bromide solution in an amount that is considerably higher than the amount theoretically necessary for converting all the silver chloride. The emulsion is then kept for a certain time at 60 C.
  • the emulsion After the emulsion has been chilled and allowed to gel for 6 hours the emulsion is noodled. The noodles are washed for 1 hour with water (10 litres of water per minute).
  • the emulsion layer is overcoated with a conventional hardened gelatin antistress layer.
  • the light-sensitive silver halide material obtained is exposed for 1/ 10,000 sec. through a step-wedge by means of a flash exposure of 130 lux sec.
  • a first strip of this image-wise exposed light-sensitive material is developed for 2 min. at 20 C. in a surface developer of the following composition:
  • a second strip of the above image-wise exposed lightsensitive material is treated in the same way as the first strip with the difference, however, that 30 see. after the development has started the light-sensitive material is overall exposed for the remaining time of the development through a grey filter having a density of 2.4 by means of a 15-watt lamp placed at a distance of 45 cm. from the light-sensitive material.
  • the densities obtained at thelvarious log exposure (log E) values are represented by curve II of the accompanying drawing.
  • a third strip of the above image-wise exposed lightsensitive material is treated in the same way as the first strip with the difference, however, that the developer comprises in addition to the above ingredients 5 g. of anhydrous sodium thiosulphate per litre so that it is an internal developer.
  • the densities obtained at the various log exposure (log E) values are represented by curve III of the accompanying drawing.
  • EXAMPLE 8 A light-sensitive silver halide emulsion is prepared in an analogous way as described in Example 7 with the difference however, that now a smaller amount of potassium bromide is used in order to convert the silver chlo ride emulsion into a silver bromide emulsion, and that just before coating, the following series of solutions is added to the emulsion instead of those listed in Example 7:
  • the light-sensitive silver halide emulsion is coated practically immediately after the addition of the above solutions on a cellulose triacetate film support provided with a gelatin subbing layer in such a way that an amount of silver halide equivalent to 8 g. of silver nitrate is present per sq. m. of light-sensitive material.
  • the light-sensitive material is exposed in a camera, the exposure being as for material having a film speed of ASA.
  • the material is then developed at 25 C. in a surface developer as described in Example 7.
  • the light-sensitive material is developed for another 3 min. 30 sec. while being overall exposed at both sides through a grey filter having a density of 2.4 by means of a 15-watt lamp placed at a distance of 45 cm. from the light-sensitive material.
  • EXAMPLE 9 A light-sensitive silver halide material is prepared in an analogous way as described in Example 7 with the only difference that in addition to the potassium bromide a lit- 1 7 tle potassium iodide is used in the conversion of the silver chloride emulsion until finally a silver bromoiodide emulsion comprising only a minor amount of silver iodide is obtained.
  • EXAMPLE A light-sensitive silver halide material is prepared as described in Example 7 with the difference, however, the 500 g. of an aqueous solution of 25 g. of gelatin and 17 g. of the following colour coupler are added to the gelatino silver halide emulsion just before the addition of the final series of solutions.
  • the light-sensitive material obtained is image-wise exposed with daylight for 1/20 sec. through a step-wedge.
  • the light-sensitive material is developed at 28 C. in a developer of the following composition:
  • the material is treated in a stop bath, bleached, fixed and rinsed with water as is the case with conventional photographic colour material.
  • a magenta coloured direct positive image of the step-wedge is obtained showing dark areas with good density and nearly pure white areas.
  • a gelatino silver bromide emulsion that forms a latent image predominantly in the inner part of the silver halide grains is prepared through conversion of a silver chloride emulsion by very slowly adding to said emulsion whilst stirring a 35% aqueous potassium bromide solution in an amount that is 70% higher than the amount theoretically necessary for converting all the silver chloride.
  • the emulsion is then kept for 1 hour at 60 C.
  • the emulsion After the emulsion has been chilled and allowed to gel for 6 hours the emulsion is noodled.
  • the noodles are washed for 1 hour with water (10 litres of water per minute). By heating the washed noodles a liquid silver bromide emulsion is obtained containing 50 g. of gelatin and 0.8 mole of silver bromide per kg.
  • the light-sensitive emulsion obtained is coated, practically immediately after the addition of the molecular iodine, on a baryta-coated paper support of 130 g./sq. m. in such a way that an amount of silver halide equivalent to 4 g. of silver nitrate is present per sq. m. of light-sensitive material.
  • the emulsion layer is over-coated with a conventional hardened gelatin antistress layer.
  • the silver halide material is image-wise exposed for 1/ 10,000 sec. through a step-wedge by means of a flash exposure of lux sec. Then the material is developed for 4 min. at 20 C. in a surface developer of the following composition:
  • the light-sensitive material is overall exposed for the remaining time of the development through a grey filter having a density of 2.7 by means of a 15-Watt lamp placed at a distance of 70 cm. from the light-sensitive material.
  • the lightsensitive material is then fixed, rinsed and dried in the conventional way.
  • a direct positive image of the original is obtained having a low minimum density and a high maximumv density.
  • the direct positive images obtained according to the method of the invention as described in this example shows a much higher maximum density and practically the same minimum density.
  • EXAMPLE 12 A gelatino silver bromide emulsion that forms a latent image predominantly in the inner part of the silver halide grains was prepared through conversion of a silver chloride emulsion by very slowly adding to said emulsion whilst stirring a 35 aqueous potassium bromide solution in an amount that was 70% higher than the amount theoretically necessary for converting all the silver chloride. The emulsion was then kept for 1 hour at 60 C. After the emulsion had been chilled and allowed to gel for 6 hours it was noodled. The noodles were washed for 1 hour with water (10 litres of water per minute). By heating the washed noodles a liquid silver bromide emulsion Was obtained containing 50 g. of gelatin and 0.4 mole of silver bromide per kg.
  • the emulsion layer was provided with a conventional hardened gelatin antistress layer.
  • the light-sensitive material was image-wise exposed for 1 second through a step wedge having a wedge constant of 0.1 'by means of a low intensity lamp. It was then developed for 65 seconds at 30 C. in a developer having the following composition:
  • a second direct positive image was prepared in an analogous manner with the difiFerence, however, that the potassium bromide and the potassium iodide were omitted from the light-sensitive material and instead thereof were incorporated into the developer by adding 20 cc. of a 10% aqueous solution of potassium bromide and 10 cc. of a 1% aqueous solution of potassium iodide per litre of developer.
  • the amounts of potassium bromide and potassium iodide in the developer had been chosen in such a way that the most favourable result was obtained.
  • the direct positive image thus obtained shows a low minimum density (0.30) indeed, but also shows too low a gradation and maximum density (0.95).
  • EXAMPLE 13 A direct positive image was prepared as the first direct positive image described in Example 12. This direct positive image shows a good gradation, a low minimum density (0.32) and a high maximum density (1.66).
  • a second direct positive image was prepared in an analogous manner with the dilference, however, that 1- (o-methoxyphenyl)-2-tetrazoline 5 thione was omitted from the light-sensitive material and instead thereof was incorporated into the developer by adding 25 cc. of a 5% solution in ethanol per litre of developer.
  • the amount of fog-inhibiting compound in the developer had been chosen in such a way that the most favorable result was obtained.
  • the direct positive image thus obtained shows a somewhat lower minimum density (0.24) indeed, but also shows a considerably lower maximum density (1.25) and a lower gradation.
  • EXAMPLE 14 A series of direct positive images was prepared in an analogous manner as the first direct positive image described in Example 12. However, instead of adding 20 cc. of a 5% solution of 1-(o-methoxy-phenyl)-2-tetrazoline-S-thione in ethanol per kg. of the liquid silver bromide emulsion, the fog-inhibiting compounds listed in the table hereinafter were added to the liquid emulsion in the given amounts.
  • a light-sensitive material which comprises a layer of an unfogged silver halide emulsion of the type that forms a latent image predominantly in the inner part of the silver halide grains,
  • the improvement which comprises incorporating within said emulsion layer subsequent to precipitation of the silver halide of said emulsion a compound other than silver iodide releasing iodide ions in an aqueous medium in an amount suflicient to effectively increase the density and contrast of the direct positive image in said emulsion layer.
  • said foginhibiting compound is a five-membered heterocyclic thione compound carrying an aryl substituent or a fusedon aromatic group.
  • said foginhibiting compound is l-(o-rnethoxy-phenyl)-2-tetrazoline-S-thione.
  • a method according to claim 3 wherein a compound releasing bromide ions in an aqueous medium, this compound being other than silver bromide, is incorporated within said emulsion layer subsequent to precipitation of the silver halide of said emulsion.
  • said moistening agent is a polyalkylene glycol.
  • the silver halide emulsion is a silver bromide emulsion or a silver chlorobromide emulsion comprising at least 20 mole percent of silver bromide and containing at most 5 mole percent of silver iodide relative to the total amount of silver halide.
  • a light-sensitive material which comprises a layer of an unfogged silver halide emulsion of the type that forms a latent image predominantly in the inner part of the silver halide grains,
  • the improvement which comprises incorporating within said emulsion layer subsequent to precipitation of the silver halide of said emulsion a compound other than silver iodide releasing iodide ions in an aqueous medium in an amount sufiicient to effectively increase the density and contrast of the direct positive image in said emulsion layer.
  • said foginhibiting compound is a five-membered heterocyclic thione compound carrying an aryl substituent or a fusedon aromatic group.
  • a method according to claim 19, wherein said foginhibiting compound is 1-(o-methoxy-phenyl)-2-tetrazoline-S-thione.
  • a method according to claim 19, wherein the silver halide emulsion is a silver bromide emulsion or a silver chlorobromide emulsion comprising at least 20 mole percent of silver bromide and containing at most 5 mole percent of silver iodide relative to the total amount of silver halide.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Silver Salt Photography Or Processing Solution Therefor (AREA)
US00111705A 1965-04-30 1971-02-01 Method of producing direct positive images with photographic silver halide material containing compound releasing iodide ions Expired - Lifetime US3708298A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB18335/65A GB1150553A (en) 1965-04-30 1965-04-30 A Method of Producing Photographic Images

Publications (1)

Publication Number Publication Date
US3708298A true US3708298A (en) 1973-01-02

Family

ID=10110704

Family Applications (2)

Application Number Title Priority Date Filing Date
US00111705A Expired - Lifetime US3708298A (en) 1965-04-30 1971-02-01 Method of producing direct positive images with photographic silver halide material containing compound releasing iodide ions
US00111706A Expired - Lifetime US3733198A (en) 1965-04-30 1971-02-01 Direct positive processes utilizing silver halide internal latent image emulsions containing high concentration of heterocyclic thione antifoggants

Family Applications After (1)

Application Number Title Priority Date Filing Date
US00111706A Expired - Lifetime US3733198A (en) 1965-04-30 1971-02-01 Direct positive processes utilizing silver halide internal latent image emulsions containing high concentration of heterocyclic thione antifoggants

Country Status (8)

Country Link
US (2) US3708298A (US06252093-20010626-C00008.png)
AT (2) AT283909B (US06252093-20010626-C00008.png)
BE (2) BE680392A (US06252093-20010626-C00008.png)
CH (2) CH477710A (US06252093-20010626-C00008.png)
DE (2) DE1522374C2 (US06252093-20010626-C00008.png)
GB (1) GB1150553A (US06252093-20010626-C00008.png)
NL (2) NL6605890A (US06252093-20010626-C00008.png)
SE (1) SE347362B (US06252093-20010626-C00008.png)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4165986A (en) * 1973-07-27 1979-08-28 Polaroid Corporation Substituted-halide silver halide emulsions and products containing same
US4954427A (en) * 1986-06-12 1990-09-04 Fuji Photo Film Co., Ltd. Process for the formation of direct positive images

Families Citing this family (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3622318A (en) * 1970-03-20 1971-11-23 Eastman Kodak Co Photographic materials and processes
US3761276A (en) * 1971-03-10 1973-09-25 Eastman Kodak Co Photographic element containing monodispersed unfogged silver halide grains chemically sensitized internally and externally
US4081281A (en) * 1972-02-18 1978-03-28 Agfa-Gevaert N.V. Developing low fogged, direct-positive silver halide emulsion with an energetic developer free from halide ions
US4105450A (en) * 1973-07-27 1978-08-08 Fuji Photo Film Co., Ltd. Spectrally sensitized positive light-sensitive o-quinone diazide containing composition
DE2406515C3 (de) * 1974-02-12 1978-06-15 Du Pont De Nemours (Deutschland) Gmbh, 4000 Duesseldorf Photographisches Material für die Herstellung von Direktpositiven
DE2416814A1 (de) * 1974-04-06 1975-10-16 Agfa Gevaert Ag Direktpositives photographisches material
US4262086A (en) * 1978-06-22 1981-04-14 F. F. D., Inc. Photograph developing solution
JPS5870223A (ja) * 1981-10-22 1983-04-26 Konishiroku Photo Ind Co Ltd 直接ポジ画像形成方法
JPS58120248A (ja) * 1982-01-12 1983-07-18 Konishiroku Photo Ind Co Ltd 直接ポジ画像形成方法
JPS63239439A (ja) * 1986-11-25 1988-10-05 Konica Corp 直接ポジハロゲン化銀写真感光材料
JPH0690436B2 (ja) * 1987-12-02 1994-11-14 富士写真フイルム株式会社 直接ポジ写真感光材料
JPH0690437B2 (ja) 1987-12-02 1994-11-14 富士写真フイルム株式会社 直接ポジ写真感光材料

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DD4420A (US06252093-20010626-C00008.png) *
BE388620A (US06252093-20010626-C00008.png) * 1926-05-21
BE489282A (US06252093-20010626-C00008.png) * 1948-05-27

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4165986A (en) * 1973-07-27 1979-08-28 Polaroid Corporation Substituted-halide silver halide emulsions and products containing same
US4954427A (en) * 1986-06-12 1990-09-04 Fuji Photo Film Co., Ltd. Process for the formation of direct positive images

Also Published As

Publication number Publication date
AT283908B (de) 1970-08-25
DE1522374C2 (de) 1982-04-01
CH475579A (de) 1969-07-15
US3733198A (en) 1973-05-15
BE680391A (US06252093-20010626-C00008.png) 1966-11-03
CH477710A (de) 1969-08-31
AT283909B (de) 1970-08-25
SE347362B (US06252093-20010626-C00008.png) 1972-07-31
DE1522374A1 (de) 1969-08-14
DE1522373C3 (de) 1981-07-23
NL6605890A (US06252093-20010626-C00008.png) 1966-10-25
NL6605891A (US06252093-20010626-C00008.png) 1966-10-25
GB1150553A (en) 1969-04-30
BE680392A (US06252093-20010626-C00008.png) 1966-11-03
DE1522373A1 (de) 1969-07-17
DE1522373B2 (de) 1980-12-11

Similar Documents

Publication Publication Date Title
US3761276A (en) Photographic element containing monodispersed unfogged silver halide grains chemically sensitized internally and externally
US2588982A (en) Direct positive photographs using hydrazine in the emulsion
US3708298A (en) Method of producing direct positive images with photographic silver halide material containing compound releasing iodide ions
US3935014A (en) Direct-positive photographic emulsion containing, unfogged, monodispersed silver halide grains having a layered grain structure of specific silver chloride content
US3647460A (en) Method of producing photographic images by rapid processing
US3033682A (en) Radiation-sensitive emulsions, elements, and processes for making same
US3923513A (en) Direct positive processing of silver halide with metal dopants in diffusion transfer films
US3957488A (en) Photographic emulsion containing unfogged, heterodisperse layered silver halide grains having a prodominantly bromide core and total chloride content less than 30 mole percent
JPS6364776B2 (US06252093-20010626-C00008.png)
US3850637A (en) Processes for obtaining positive images in silver halide compositions
US3536487A (en) Photographic elements and processes for producing therein interimage effects with diffusible 4 - thiazoline-2-thione
US4263396A (en) Direct-positive photographic material
US3708300A (en) Silver-dye-bleach photographic materials
US4440851A (en) Method for the formation of a direct positive image
US4332885A (en) Photographic sensitive materials for color diffusion transfer process
US3178292A (en) Direct-print photographic silver halide emulsions
US3565620A (en) Photographic processing liquids and method of producing photographic images
US3637387A (en) Direct positive emulsion containing a halide releasing compound developed in the presence of an unsubstituted hydrazine
US3591385A (en) Silver halide emulsions sensitized with a combination of sulfur and selenium for color photography
US1582050A (en) Photographic print-out paper and prints made therefrom
US3637388A (en) Process for the photographic production of equidensities
JPS5931060B2 (ja) 多色写真画像の生成方法
US3816135A (en) Direct positive silver halide emulsions through synergistic effects of fogging agents and organic reducing agents and/or their oxidized forms
US3413122A (en) Process for forming images and elements therefor
US4910130A (en) Direct positive light-sensitive silver halide photographic material