US3091530A - Photographic products, processes and compositions - Google Patents

Photographic products, processes and compositions Download PDF

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US3091530A
US3091530A US861127A US86112759A US3091530A US 3091530 A US3091530 A US 3091530A US 861127 A US861127 A US 861127A US 86112759 A US86112759 A US 86112759A US 3091530 A US3091530 A US 3091530A
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exposure
emulsion
silver
silver halide
layer
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Green Milton
Meroe M Morse
Myron S Simon
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Polaroid Corp
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Polaroid Corp
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Priority to BE598399D priority Critical patent/BE598399A/xx
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Priority to US861127A priority patent/US3091530A/en
Priority to GB41007/60A priority patent/GB900155A/en
Priority to FR847191A priority patent/FR1281492A/fr
Priority to DEJ19196A priority patent/DE1183785B/de
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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
    • G03C8/00—Diffusion transfer processes or agents therefor; Photosensitive materials for such processes
    • G03C8/02—Photosensitive materials characterised by the image-forming section
    • G03C8/04—Photosensitive materials characterised by the image-forming section the substances transferred by diffusion consisting of inorganic or organo-metallic compounds derived from photosensitive noble metals
    • G03C8/06—Silver salt diffusion transfer

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  • the present invention relates to photography and more particularly to compositions, products, and processes useful in the development of selectively photoexposed photosensitive silver halide elements, and especially to compositions and products useful in diffusion transfer processes, particularly in high speed diffusion processes Wherein a silver halide photosensitive emulsion has been underexposed in relation to its A.S.A. exposure index, that is, to processes for deriving useful photographic transfer prints from latent images formed at low exposure levels.
  • a latent image contained in a selectively photoexposed photosensitive silver halide emulsion is developed. Almost concurrently therewith a soluble silver complex is obtained by reaction of a silver halide solvent with the unexposed and undeveloped silver halide of said emulsion.
  • the photosensitive silver halide emulsion is developed with a processing composition in a viscous condition which is spread between the photosensitive element comprising the silver halide emulsion, and a print-receiving element comprising, preferably, a suitable silver precipitating layer.
  • the processing composition effects development of the latent image in the emulsion and substantially contemporaneous therewith forms a soluble silver complex, for example, a thiosulfate or thiocyanate complex, with undeveloped silver halide.
  • a soluble silver complex for example, a thiosulfate or thiocyanate complex
  • This soluble silver complex is, at least in part, transported in the direction of the print-receiving element and the silver thereof is largely precipitated in the silver precipitating layer of said element to form the desired positive image therein.
  • High speed diffusion transfer processes are generally of the type in Which, for example, a silver halide stratum containing a latent image formed at a low exposure level and an image-receiving stratum, in superposition, are subjected to a processing composition containing a highly energetic silver halide developing agent and a silver halide solvent in order to form a silver transfer print in and/ or on the image-receiving stratum.
  • the silver halide developing agent serves to reduce photoexposed silver halide to silver in the photosensitive emulsion stratum.
  • the silver halide solvent reacts with unreduced silver halide, to form the aforementioned soluble silver complex which, in turn, is reduced in the presence of the image-receiving stratum to form the desired positive print.
  • the photosensitive stratum may be subsequently dissociated from the image-receiving stratum.
  • the silver halide stratum may be underexposed in relation to its rated A.S.A. exposure index and the silver halide developing agent is specifically selected from the class hereinafter set forth.
  • the image-receiving stratum is in such condition as to cause silver reduced there, in comparison with silver reduced in the photosensitive silver halide stratum, to possess very high covering power, that is, opacity per given mass of reduced silver.
  • This high covering power is achieved by accumulating the silver deposited in the ggt silver-receptive stratum in unusually dense masses, for example, by minimizing the thickness of the stratum in which the silver-receptive material is contained.
  • the high speed diffusion transfer processes set forth herein provide readily available and uniquely simple processes for producing satisfactory high quality of good resolunch and trivial granularity at low illumination levels, for example, at overall exposures that are equivalent to A.S.A. exposure indices of 600 and up.
  • objects of the present invention are to provide: novel products, developer composition, and processes employing such products and developer compositions, for the development of selectively photoexposed silver halide emulsions; novel products and developer compositions useful in high speed diffusion transfer processes wherein a selectively photoexposed silver halide emulsion has been substantially underexposed in relation I to its A.S.A. exposure index; and to employ, in processes of the aforementioned type, a silver halide developing agent selected from the class hereinafter set forth.
  • the invention accordingly comprises the several steps and the relation and order of one or more of such steps with respect to each of the others, and the products and compositions possessing the features, properties and the relation of elements which are exemplified in the following detailed disclosure, and the scope of the application of which will be indicated in the claims.
  • FIGURE 1 is a diagrammatic enlarged cross-sectional View illustrating the association of elements during one stage of the performance of a diffusion transfer process, for the production of positive silver prints, the thickness of the various materials being exaggerated;
  • FIG. 2 is a view similar to that of FIGURE 1 illustrating the association of elements during one stage of the performance of another diffusion transfer process, for the production of positive silver prints.
  • amidol (2,4-diaminophenol hydrochloride) is an energetic silver halide developing agent which has received only limited use in general photography due to its rapid oxidation in solution.
  • amidol may be employed in diffusion transfer processes by incorporating it in a rupturable container which is substantially airtight. It has been found, however, that use of amidol in diffusion transfer processes gives rise to a deeply colored oxidation product which will stain the hands and clothes of the person performing the transfer process.
  • This deeply colored oxidation product apparently is formed after the processing composition has been spread between the photosensitive and image-receiving elements.
  • the layer of processing, composition preferentially adheres to the developed photosensitive element, and will stain objects, e.g., hands or clothes, with which it comes into contact.
  • the silver halide developing agents of this invention possess many of the desirable properties of amidol but do not give rise to highly colored oxidation products in diffusion transfer processes. These new silver halide developing agents also are substantially more stable than amidol when employed in tray or tank processing in general photography.
  • novel class of silver halide developing agents of the present invention may b? represented by the formula:
  • R or R comprises a benzyl group, or a hydroxybenzyl group, and the remaining R or R is hydrogen; and the nuclear substituted halogen derivatives, preferably the nuclear substituted chlorine derivatives thereof.
  • the developing agents of the present invention may be employed in the form of their acid addition salts, such as the hydrochloride.
  • Thefollowing compounds are examples of silver halide developing agents within the scope of the present invention:
  • a preferred method of preparing the compounds of Formula A comprises reacting either an o-amino-p-nitrophenol or a p-amino-o-nitro-phenol with either benzaldehyde or hydroxybenzaldehyde and efiecting reduction of the resultant product, for example, by hydrogenation in the presence of a suitable catalyst such as palladium on barium sulfate.
  • a mixture comprising 12.1 grams of the Schiff base product, 6 grams of 5% palladium on barium sulfate, and 200 cc. of ethyl acetate was hydrogenated in a Parr shaker bottle at an initial pressure of approximately 35 pounds per square inch. The bottle was shaken until the theoretical amount of hydrogen Was absorbed (20 to 30 minutes). The mixture was then filtered through a Celite (trade name of Iohns-Manville Sales Corp., New York, N.Y., for diatomaceous-earth filtration aids) pad into concentrated hydrochloric acid. The product, 4- amino-2-benzylamino-phenol, a white solid, precipitated spontaneously from the acid solution as the hydrochloride. The precipitate was separated by filtration, washed with ether anddried in a vacuum desiccator over potassium hydroxide. [Yield 89.2%.]
  • novel silver halide developing agents of the present invention are useful in conventional black-and-white development and in diffusion transfer processes, both dye and silver. Examples of such processes are disclosed in U.S. Patents Nos. 2,543,181 and 2,662,822 to Edwin H. Land.
  • novel silver halide developing agents of the present invention are highly useful in so-called high speed diffusion transfer processes wherein high quality silver transfer prints are obtained from a silver halide emulsion which has been substantially underexposed in relation to its A.S.A. rating. Such an exposure provides a latent image having a density gradient confined to the low exposure or toe region of the negative materials characteristic curve. Processes of this type are disclosed in the copending application of Edwin H. Land et al., Serial No. 564,492, filed February 9, 1956.
  • the speed of a photosensitive material comp-rises generally an empirically derived relative measurement which may be defined as a value representing the reciprocal of the exposure required to produce a given result. Any precise definition of speed, therefore, is based upon the selection of a particular result as the standard reference point.
  • a precise quantitative measure of speed has been developed from the work of L. A. Jones et al., as reported in Mees, The Theory of the Photographic Process, the Macmillan Company, New York, 1944, Chapters XIX and XXII. This work suggested a system in which negative sensitive materials are assigned a speed that is in terms of the exposure required to give a negative image from which a positive print of specified quality can be produced.
  • emulsion speed is considered as a value inversely proportional to the minimum exposure which must be incident upon the negative material, from the scene element of minimum brightness in which detail is visible, in order that a print of excellent quality can be made from the resultant negative.
  • These standards specify techniques for plotting the characteristic H. and D. curve of a negative material, that is, the curve relating the logarithm of the original exposure of the negative to density in said negative.
  • the value of speed derived from the standard characteristic curve so determined is specified as equal to the reciprocal of the exposure E, on the characteristic curve at which the slope is 0.3 times the average slope for a log exposure range of 1.5 of which E is the minimum exposure.
  • the precise method for determining speed in this manner is described in detail in the publication of The American Standards Association, Inconporated, PH 2.51954, and titled American Standard Method for Determining Photographic Speed and Exposure Index.
  • the A.S.A. speed rating is to be distinguished from What is termed the A.S.A. exposure index, for use with exposure meters and calculators.
  • the exposure index so obtained indicates generally the correct exposure rating to which an A.S.A. calibrated exposure meter must be set in order that it give correct exposure data for producing pictures of satisfactory high quality.
  • the ASA speed rating is to be further distinguished from what may be termed diffusion transfer process exposure index.
  • the exposure index may be based on a curve relating original exposure of the negative to the density in the resultant positive. It has been found experimentally that the diffusion transfer exposure index of a silver transfer process may be determined by plotting a characteristic curve of the reflection density of the positive as a function of the log exposure of the negative, determining the exposure in meter-candleseconds (m.c.s.) at the point on this curve corresponding to a density of 0.50, and dividing the constant, 4.0, by the exposure so determined.
  • the exposure index so obtained indicates generally the correct exposure rating of a silver transfer process to which an exposure meter, calibrated to the A.S.A. exposure index, must be set in order that it give correct exposure data for producing transfer prints of satisfactory high quality, and is sometimes referred to as the equivalent A.S.A. exposure index.
  • Both the A.S.A. exposure index and the diffusion transfer exposure index can "be judged or rated according to sensitometric criteria with exposure, that is, the luminance flux reaching a unit :area of the photosensitive surface, being measured inm.c.s.
  • sensitometric criteria with exposure that is, the luminance flux reaching a unit :area of the photosensitive surface, being measured inm.c.s.
  • the equivalence of the foregoing methods of determining rated A.S.A. exposure indices and diffusion transfer exposure indices can be readily established by obtaining a standardized silver transfer positive and determining the illumination, by measuring with an exposure meter calibrated according to an A.S.A. standard which includes a computer in which has been entered the shutter duration and f-stop of the camera, found necessary to provide the standard transfer print.
  • the term A.S.A. exposure index is intended to signify the exposure index determined in accordance with the aforementioned American Standards Association specifications.
  • the term diffusion transfer exposure index is intended to signify, in reference to diffusion transfer processes, or the materials used therein, the exposure index as determined in the aforementioned manner. Both designations, in one sense, serve the same purpose.
  • the A.S.A. exposure index of the negative is based upon the exposure to which the negative must be subjected in order to obtain a good photograph of a predetermined subject by conventional processing, whereas the diffusion transfer exposure index is based upon the exposure to which a negative for use in a silver diffusion transfer process must be subjected in order to obtain a good positive by that process.
  • This negative material may be employed, for example, in a silver diffusion transfer process of the present invention to effect a diffusion transfer exposure index vastly different from the A.S.A. exposure index of the negative material.
  • a positive print of satisfactory high quality is produced from a negative material subjected to exposures less, in some cases many times less, than recommended by its rated A.S.A. exposure index.
  • Such an exposure provides a latent image having a density gradient confined to the low exposure or toe region of the negative materials characteristic curve.
  • FIGURE 1 illustrates one assemblage and process of the present invention in the performance of a diffusion transfer process for the production of positive silver prints.
  • an aqueous allkaline fi-uid layer 12 of a silver halide developing agent chosen in accordance with the present invention and a suitable silver halide solvent are spread between photosensitive emulsion layer 11 which is superposed on support It) and image receiving layer 13 which is aflixed to support layer 14.
  • Image-receiving layer 13 preferably contains silver precipitating agents or nuclei such as the silver precipitating nuclei disclosed in U.S. Patent No. 2,698,237.
  • Support layer 14 may comprise an opaque material where a reflection print is desired or may comprise a transparent material Where a transparency is desired.
  • one or more rupturable containers may be attached to either photosensitive emulsion layer 11 and/ or image-receiving layer 13 such that upon superpostiion of the respective layers 11 and 13 said container or containers are so positioned as to be capable, upon rupture, of releasing their contents in a substantially uniform layer between and in contact with the opposed surface of each of said layers.
  • Rupture of the container or containers and spreading of the contents thereof may be accomplished, for example, by compression between a pair of opposed, suitably gapped, rollers.
  • the processing composition preferably comprises a film-forming transfer processing composition. It may comprise, for example, one or more of the previously enumerated developing agents of the present invention, an alkali such as sodium hydroxide, a silver halide complexing agent such as sodium thiosulfate, and a high molecular weight film-forming thickening agent such as sodium carboxymethyl cellulose. All these materials are preferably in aqueous solution.
  • an alkali such as sodium hydroxide
  • a silver halide complexing agent such as sodium thiosulfate
  • a high molecular weight film-forming thickening agent such as sodium carboxymethyl cellulose. All these materials are preferably in aqueous solution.
  • photographic agents are preferably contained in solution in the processing composition prior to the spreading thereof as layer 12, but they may be in part or in whole added to the processing composition as it is spread between the photosensitive emulsion 11 and image-receiving layer 13, said agents being so located on, in, or adjacent to a surface of one or both of said layers as to be dissolved by or otherwise interacted with the liquid agent when the latter wets said layers.
  • the photosensitive emulsion 11 is exposed to a predetermined subject matter to form therein a latent image of said subject matter.
  • the exposed emulsion is superposed on image-receiving layer 13 and the photographic processing composition 12 spread between the opposed surfaces of said emulsion 11 and said image-receiving layer 13.
  • Reagents permeate into the photosensitive emulsion 11, developing the latent image contained therein and forming a soluble silver complex of unexposed silver halide.
  • Soluble silver complex is transported from photosensitive emulsion layer 11, at least in part,by imbibition, tosetceiving stratum 13' and the silver of the complex is precipitated thereon and/or therein to provide the desired positive image formation.
  • the laminate formed by the spreading of the processing composition as layer 12 between photosensitive emulsion layer 11 and print-receiv ing layer 13 is kept intact for approximately /2 to 1 /2 minutes, preferably 1 minute, and at the termination of this time interval the print-receiving layer 13 is dissociated from photosensitive emulsion 11 as, for example, by manual stripping.
  • FIG. .2 A further transfer process of the present invention for the production of positive silver prints is illustrated in FIG. .2 and comprises a spreader sheet 15, a layer of relatively viscous processing composition 12, a photosensitive gelatin emulsion layer 11 superposed on imagereceiving layer 13 which is, in turn, superposed on a support layer 14.
  • image-receiving layer 13 preferably contains silver precipitating nuclei and support layer 14 may comprise either an opaque or transparent material.
  • Fluid composition layer 12 may be obtained by spreading a photographic processing composition, for example, in a manner disclosed in U.S. Patent No. 2,698,244. As disclosed in the aforementioned patent, the liquid processing composition may be disposed in a rupturable container so positioned in regard to the appropriate surface of photosensitive emulsion layer 11 that, upon compression by spreader sheet 15, a substantially uniform layer 12 of processing composition is distributed over the external surface of said photosensitive emulsion 11, with respect to image-receiving layer 13.
  • the photosensitive emulsion 11 is exposed to a predetermined subject matter to form therein a latent image of said subject matter.
  • a substantially uniform distribution of processing composition 12 is distributed on the external surface of said emulsion 11, as for example, according to the previously described procedure.
  • Processing composition reagents permeate into photosensitive emulsion '12, developing the latent image contained therein according to the point-to-point degree of exposure thereof.
  • an imagewise distribution of soluble silver complex is formed from unexposed and undeveloped silver halide within said emulsion.
  • At least part of said silver complex, solubilized, is transferred, by imbibition, to print-receiving stratum 13.
  • the transferred silver complexes are reacted therein to provide a positive, reversed image of the latent image.
  • dissociation of said layer from emulsion layer 11 may be effected.
  • the image-receiving layer 13 may be dissociated from emulsion layer 11 by stripping the emulsron from the surface thereof.
  • a conventional stripping layer may be provided to facilitate separation of emulsron layer 11 from image-receiving layer 13 subsequent to transfer processing.
  • Sufficient abrasion-resistant properties may be provided to image-receiving layer 13 as to alleviate anynecessity of subsequently overcoating the external surface of said image-receiving layer 13 with a transparent abrasion-resistant water-soluble plastic to prevent subsequent laceration and resultant degradation of the positlve image.
  • Image-receiving layer 13 may also comprise sufficient integral dimensional stability as to alleviate the necessity of a separate support layer 14.
  • spreading of the liquidprocessing composition on the external surface of photosensitive emulsion layer 11 is preferably effected by rup ture of a suitably positioned frangible container and dis tribution of its processing composition contents by means of a converted cellulose acetate spreader sheet, that is, a cellulose acetate sheet the surface of which has been converted to cellulose.
  • the converted cellulose acetate spreader sheet may exhibit an adhesive capacity for the processing composition in excess of the adhesive capacity exhibited by the photosensitive ernulsion.
  • a means is thus provided for effecting dissociation of the processing composition from contact with the photosensitive emulsion, subsequent to image formation, by dissociating the spreader sheet from its proximate relationship to the external emulsion surface.
  • the facility with which the photosensitive emulsion layer is dissociated from contact with the print-receiving layer may be increased by providing a conventional stripping layer interposed between said emulsion and said print-receiving layer.
  • the stripping layer may be coated on the surface of the print-receiving element and a photosensitive emulsion thereafter coated on the external surface of said stripping layer.
  • a photosensitive element after exposing a suitable apparatus and While preventing further exposure thereafter to actinic radiation, may be removed from such apparatus and permeated with the liquid processing composition as, for example, by coating, spraying, flowing etc., the composition on said photosensitive element or otherwise wetting said ele: ment with a composition, following which the permeated, exposed, photosensitive element, still without additional exposure to actinic radiation, is brought into contact with the image-receiving element for image formation in the manner heretofore described.
  • the rupturable containers may be constructed in accordance with the disclosures set forth in U.S. Patent No. 2,634,886.
  • Containers of this type are generally constructed from a blank comprising a flexible, deformable, three-ply sheet material comprising, respectively, an outer layer of kraft paper, a layer of metal foil and an inner layer or liner of a thermoplastic resin.
  • the container blank is folded upon itself such as to provide a fluid-containing cavity and a container exhibiting a sealed passage adjacent to an edge thereof which may be substantially uniformly unsealed throughout a predetermined length of the seal passage upon application of stress to the container.
  • the passage may be formed by the utilization of differential adhesion.
  • the print-receiving stratum preferably contains silver precipitating agents or nuclei, whose presence during the transfer process has a desirable efiect on the amount and character of the silver precipitated during positive print formation.
  • silver precipitating agents are the metallic sulfides and selenides, thiooxalates, and the thioacetarnides, and colloidal metals disclosed in U.S. Patent No. 2,698,237.
  • a suitable water-insoluble, inorganic, preferably siliceous, material such as silica aerogel.
  • Silver halide solvents suitable for incorporation in the processing composition include conventional fixing agents such as sodium thiosulfate, sodium thiocyanate, ammonium thiosulfate, or associations of cyclic imides and hitrogeneous bases such as associations of barbiturates or uracils and ammonia or amines. Of these, the conventional fixing agents specified are preferred.
  • the solution also contains a film-forming material such as a water-soluble plastic, starch or gum imparting a viscosity of from 1000 to 200,000 centipoises at a temperature of 10 20 C. in order to permit the solution to be readily con trolled during and after spreading.
  • the relative proportions of the agents of the developer composition set forth herein may be altered to suit the requirements of the operator.
  • modify the herein described developing compositions by the substitution of preservatives, alkalies, silver halide solvents, etc., other than those specifically mentioned.
  • concentration of developing agent may be varied over a wide range and when desirable the developing agent may be disposed in the photosensitive element prior to the exposure of the emulsion.
  • the developing agent may be disposed in a separate permeable layer of the photosensitive element and/or in the photosensitive emulsion.
  • the emulsion support layer designated in the drawing as 10 may comprise any of the various types of conventional rigid or flexible supports, for example, glass, paper, metal, and polymeric films of both the synthetic types and those derived from naturally occurring products.
  • the photosensitive emulsion stratum may comprise a commercially available silver halide gelatin emulsion such as sold by Eastman Kodak Company under the trade names Microfile, Spectrum Analysis, Contrast Process, S X X Aero Recon, Ve-richrome, Royal Pan, Royal X Pan, or Tri X Pan, or sold by E. I. du Pont under the trade names Fine Grain Pan, High Speed Pan, Arrow Pan, or Superior 3, or sold by Ansco under the trade name Triple S Pan, or sold by Gevaert under the trade name Gevapan.
  • a commercially available silver halide gelatin emulsion such as sold by Eastman Kodak Company under the trade names Microfile, Spectrum Analysis, Contrast Process, S X X Aero Recon, Ve-richrome, Royal Pan, Royal X Pan, or Tri X Pan, or sold by E. I. du Pont under the trade names Fine Grain Pan, High Speed Pan, Arrow Pan, or Superior 3, or sold by Ansco under the trade name Triple S Pan, or sold by Gevaert under
  • R or R comprises a hydroxybenzyl group possess specific and unexpected advantages. These compounds are characterized by unexpectedly higher process speeds when employed in diffusion transfer processes. The higher process speeds may be the result of a solubilizing effect imparted to the developer molecule by the hydroxyl group substituted on the benzyl group.
  • the compounds of the present invention may also be used in small quantities with other silver halide developers, for example, hydroquinone or one of its derivatives, to produce high speed prints of exceptional quality by diffusion transfer processes.
  • other silver halide developers for example, hydroquinone or one of its derivatives
  • 6-nitrobenzimidazole 2 do 0.5
  • the present mvention obviates the problem of conwhlch provided satisfactory contrast, denslty and range. structmg a satisfactory negative from an underexposed Concentration Imbibi- Density Density Diffusion Emulsion Shoulder Compound (grams/ tion (maxi- (mini- Slope Transfer A.S.A. Speed cc. process- Tune mum) mum) Exposure Exposure (m.s.c.)
  • the emulsions possessing an A.S.A. exposure index of ca. 800 are coated on the external surface of arefiecting layer which is on a paper base; the A.S.A. exposure index ca. 800 was determined experimentally.
  • the chief function of a photographic negative material as used in pictorial photography is to reproduce as density differences the luminance differences existing in the object photographed.
  • the minimum useful exposure will, therefore, be that required to reproduce the minimum difference existing in the shadow regions of the object by means of some minimum density difierence in the resulting image.
  • the region of the A.S.A. characteristic curve of the negative used in accordance with the present invention lies at a relatively low exposure level and corresponds to an exposure gradient predominantly below approximately 0.015 m.c.s.
  • the fog level in such a case is at a point on the characteristic curve that corresponds to an exposure gradient predominantly above approximately 0.005 m.c.s.
  • the shoulder speed is the minimum amount of exposure in motorcandle-seconds which can be used to expose the negative emulsion and give a transfer image in which there is the minimum contrast which the eye can distinguish, i.e., there is visible detail in the shadow regions of the transfer image.
  • This exposure level is determined at the point on the shoulder portion of the previously described characteristic curve of the positive transfer image where the slope is 0.4.
  • the photosensitive emulsions of the present processes are underexposed in relation to their respective A.S.A. exposure index to produce therein a weak latent imagehaving an exposure gradient predominantly in the toe region of the A.S.A. density versus log exposure curve of the photosensitive emulsion.
  • the emulsion is therefore exposed to produce a latent image lying in the toe region of the A.S.A. characteristic curve for the negative emulsion such that, by the standard A.S.A. development method, it would be impractical to develop the emulsion such as to provide a useful conventional negative image.
  • compositions, products and processes of the present invention one may advantageously employ a photosensitive emulsion having a stated A.S.A. exposure index and provide said emulsion with an effective exposure that ordinarily would require a photosensitive emulsion having a higher A.S.A. exposure index to provide an acceptable positive print resultant therefrom.
  • the present invention provides satisfactory positive images from both underexposed and adequately exposed conventional silver halide photosensitive emulsions.
  • a convenient measure of the amplification of image development, obtained according to the present disclosure, over the results obtained from conventional development practices, is in terms of increase in the speed or quantum excitation sensitivity of the emulsion as indicated by the results previously set forth, over the normal specified speed of the same emulsion as determined by the results of standard development practice.
  • a photographic process which comprises the steps of underexposing a photosensitive silver halide emulsion with respect to its A.S.A. exposure index to produce therein a latent image having an exposure gradient in the toe region of the A.S.A. density versus log exposure curve of said silver halide emulsion; developing said emulsion with an aqueous alkaline solution of a silver halide developing agent of the formula:
  • R and R is a hydroxybenzyl group, and the other of R and R is hydrogen, and the diaminophenol nuclear substituted halogen derivatives thereof; contacting unexposed and undeveloped silver halide therein with a silver halide solvent to form an imagewise distribution of soluble silver complex; transferring at least part of said imagewise distribution, by imbibition, to a superposed image-receiving material containing a silver precipitating agent; and there precipitating transferred soluble silver complex to provide a silver print of full pictorial density to said image-receiving material.
  • a photographic process which comprises the steps of exposing a photosensitive gelatino silver halide emulsion with a luminance flux incident thereon not in excess of about 0.015 imeter-candle-second; developing exposed silver halide in said photosensitive emulsion with an aqueous alkaline solution containing a silver halide developing agent of the formula:
  • R and R is a hydroxybenzyl group, and the other of R and R is hydrogen, and the diaminophenol nuclear substituted chlorine derivatives thereof; and a silver halide solvent; contacting unexposed and undeveloped silver halide therein with said silver halide solvent and forming thereby an imagewise distribution of a soluble silver complex in unexposed areas of said emulsion, as a function of the point-to-point degree of exposure thereof; transferring from said emulsion, at least in part, by imbibition, said imagewise distribution of soluble silver complex to a print-receiving layer, containing silver precipitating nuclei, in superposed relationship, with said emulsion; and there precipitating silver complex to provide thereby a reversed, positive, full scale silver print of the latent image.
  • a photographic process which comprises the steps of exposing a photosensitive gelatino silver halide emulsion with a light flux incident thereon predominantly with- 14 in the exposure range delineated by the toe region of said emulsions characteristic H. and D. curve, determined according to A.S.A. standard PH 2.5-1954; developing exposed silver halide in said photosensitive emulsion with an aqueous alkaline solution of a silver halide developing agent of the formula:
  • Glafkides Photographic Chemistry, 1, Fountain Press, London (1958), page 125.

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  • Inorganic Chemistry (AREA)
  • Physics & Mathematics (AREA)
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  • Silver Salt Photography Or Processing Solution Therefor (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
US861127A 1959-12-21 1959-12-21 Photographic products, processes and compositions Expired - Lifetime US3091530A (en)

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BE598399D BE598399A (en, 2012) 1959-12-21
US861127A US3091530A (en) 1959-12-21 1959-12-21 Photographic products, processes and compositions
GB41007/60A GB900155A (en) 1959-12-21 1960-11-29 N-monobenzyl derivatives of 2, 4-diaminophenol and their use in photographic products, processes and compositions
FR847191A FR1281492A (fr) 1959-12-21 1960-12-16 Produits, procédés et compositions utilisés en photographie
DEJ19196A DE1183785B (de) 1959-12-21 1960-12-21 Verfahren zur Herstellung von UEbertragungsbildern nach dem Diffusionsbilduebertragungsverfahren

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BE (1) BE598399A (en, 2012)
DE (1) DE1183785B (en, 2012)
FR (1) FR1281492A (en, 2012)
GB (1) GB900155A (en, 2012)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3241964A (en) * 1962-04-10 1966-03-22 Polaroid Corp Diffusion transfer process using an oxidized 4, 6-diamino-ortho-cresol solution
US3325284A (en) * 1962-06-27 1967-06-13 Gevaert Photo Prod Nv Silver complex diffusion transfer process
US3622629A (en) * 1968-06-19 1971-11-23 Du Pont N-(hydroxy-aminobenzyl)-3-hydroxy-aniline compounds
DE1793289A1 (de) * 1967-08-28 1972-07-06 Du Pont Entwickler-Kuppler-Verbindungen und Verfahren zu ihrer Herstellung
EP0793140A1 (en) * 1996-03-04 1997-09-03 Fuji Photo Film Co., Ltd. Processing composition for silver halide photographic light-sensitive material, developer and processing method using the same

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US516754A (en) * 1894-03-20 Johann jakob brack
GB190820050A (en) * 1908-05-23 1909-05-24 Josef Hertkorn New or Improved Process for Manufacturing Camphor.
US2543181A (en) * 1947-01-15 1951-02-27 Polaroid Corp Photographic product comprising a rupturable container carrying a photographic processing liquid
US2740717A (en) * 1952-05-03 1956-04-03 Eastman Kodak Co Photographic transfer process
US2837497A (en) * 1956-09-04 1958-06-03 Furane Plastics Amine curing agent for epoxy resins

Family Cites Families (2)

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Publication number Priority date Publication date Assignee Title
US2782120A (en) * 1954-02-15 1957-02-19 Goldhammer Jerome Stewart Combined developer and fixer
BE536578A (en, 2012) * 1954-03-18

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US516754A (en) * 1894-03-20 Johann jakob brack
GB190820050A (en) * 1908-05-23 1909-05-24 Josef Hertkorn New or Improved Process for Manufacturing Camphor.
US2543181A (en) * 1947-01-15 1951-02-27 Polaroid Corp Photographic product comprising a rupturable container carrying a photographic processing liquid
US2740717A (en) * 1952-05-03 1956-04-03 Eastman Kodak Co Photographic transfer process
US2837497A (en) * 1956-09-04 1958-06-03 Furane Plastics Amine curing agent for epoxy resins

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3241964A (en) * 1962-04-10 1966-03-22 Polaroid Corp Diffusion transfer process using an oxidized 4, 6-diamino-ortho-cresol solution
US3325284A (en) * 1962-06-27 1967-06-13 Gevaert Photo Prod Nv Silver complex diffusion transfer process
DE1793289A1 (de) * 1967-08-28 1972-07-06 Du Pont Entwickler-Kuppler-Verbindungen und Verfahren zu ihrer Herstellung
US3622629A (en) * 1968-06-19 1971-11-23 Du Pont N-(hydroxy-aminobenzyl)-3-hydroxy-aniline compounds
EP0793140A1 (en) * 1996-03-04 1997-09-03 Fuji Photo Film Co., Ltd. Processing composition for silver halide photographic light-sensitive material, developer and processing method using the same
US5994040A (en) * 1996-03-04 1999-11-30 Fuji Photo Film Co., Ltd. Processing composition for silver halide photographic light-sensitive material, developer and processing method using the same

Also Published As

Publication number Publication date
FR1281492A (fr) 1962-01-12
GB900155A (en) 1962-07-04
DE1183785B (de) 1964-12-17
BE598399A (en, 2012)

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