CA1141223A - Image-receiving element including noble metal silver-precipitating nuclei in gelatin and hydroxyethyl cellulose or polyvinyl alcohol - Google Patents

Abstract

ABSTRACT OF THE INVENTION
A receiving element for use in a photographic diffusion transfer process which comprises a transparent support carrying a layer comprising noble metal silver-precipitating nuclei in a polymeric binder composition of hydroxyethyl cellulose and gelatin or polyvinyl alcohol and gelatin; wherein the nuclei are present in a level of from about 0.1-0.4 mgs/ft2 (1.1-4.3 mgs/m2).
In the embodiment employing hydroxyethyl cellulose in the polymeric binder, the hydroxyethyl cellulose is present at a level of about 0.1 to 7 mgs/ft2 (1.1 to 75.3 mgs/m2);
and in the embodiment employing polyvinyl alcohol in the polymeric binder, the polyvinyl alcohol is present at a level of about 0.1 to 5 mgs/ft2 (1.1 to 53.8 mgs/m2). In either of the embodiments, the gelatin is present at a level of from about 0.05 to 1.5 mgs/ft2 (0.54 to 16.1 mgs/m2). Preferably the noble metal is palladium. The receiving element is particularly useful in an additive color diffusion transfer process.

Description

BACKGROUND OF THE INVENTION
Procedures for preparing photographic images in silver by diffusion transfer principles are well known in the art. For the formation of the positive silver images, a latent image contained in an exposed photosensitive silver halide emulsion is developed and almost concurrently therewith, a soluble silver complex obtained by reaction of a silver halide solvent with the unexposed and undeveloped silver halide of said emulsion is transported, at least in part, to a print-receiving element comprising, preferably, a suitable silver-precipitating layer to form the positive silver image.
Additive color reproduction may be produced by exposing a photosensitive silver halide emulsion throuqh an additive color screen having filter media or screen elements each of an individual additive color, such as red or green or blue, and by viewing the reversed or positive silver image formed by transfer to a transparent print-receiving element through the same or a similar screen which is suitably registered with the reversed positive image carried by the print-receiving layer.
As examples of suitable film structures for employment in additive color photography, mention may be made of U. S. Patent Nos. 2,861,885; 2,726,154; 2,944,894;
3,536,488; 3,615,426; 3,615,427; 3,615,428; 3,615,429; and 3,894,871.
The image-receiving elements of the present invention are particularly suited for use in diffusion transfer film units wherein there is contained a positive transfer image and a negative silver image, the two images being in separate layers on a common, transparent support and viewed as a single, positive image. Such positive images may be referred to for convenience as "integral positive-negative images", and more particularly as . ~J~

11~1223 "integral positive-negative transparencies." Examples of film units which provide such integral positive-negative transparencies are set forth, for example, in the above-indicated U. S. Patents Nos. 3,536,488; 3,894,871;
3,615,426; 3,615,427; 3,615,428; and 3,615,429.
U. S. Patent No. 3,647,440, issued March 7, 1972 discloses receiving layers comprising finely divided non-silver noble metal nuclei obtained by reducing a noble metal salt in the presence of a colloid or binder material with a reducing agent having a standard potential more negative than -0.30. It is the thrust of the patent that a reducing agent having a standard potential more negative than -0.30 must be used in order to obtain nuclei of a specific, usable size range. It is further illustrated that stannous chloride, which does not fall within the standard potential range, does not produce useful nuclei. The binder materials disclosed include gelatin, polyvinyl pyrrolidone, polymeric latices such as copoly (2-chloro-ethylmethacrylateacrylic acid), a mixture of polyvinyl alcohol and the interpolymer of n-butyl acrylate, 3-acryloyloxypropane-1-sulfonic acid, sodium salt and

2-acetoacetoxyethyl methacrylate, polyethylene latex, and colloidal silica. The amount of colloid binder employed ranges from about 5 to 500 mgs/ft2 (53.8-5380 mgs/m2) with the nuclei ranging from 1 to 200 micrograms/ft2 (10.8 to 2150 mgS/m ).
Copending~appllcation Serial No. 269,685 filed January 13, 1977 discloses and claims a receiving element for use in an additive color photographic diffusion trans-fer film unit which comprises a transparent supportcarrying an additive color screen and a layer comprisin~
noble metal silver-precipitating nuclei and a polymer;
wherein the nuclei are present in a level of about 0.1 - 0.3 mgs/ft (1.1-3.3 m~s/m ), and said poly~er is Z~3 present at a level of from about 0.5 to 5 times the coverage of said nuclei. Preferably, the noble metal is obtained by reduction of a noble metal salt or complex, and more preferably, the noble metal is palladium. The preferred binder polymers are gelatin and hydroxyethyl cellulose; gelatin at the low end of the nuclei-binder ratio can be employed to provide good density, neutral tone positive images in the receiving layer whereas the preferred levels of other polymers, such as hydroxyethyl cellulose are at the higher portions of the nuclei-binder range.

Z~23 SUMMARY OF_THE INVENTION
The present invention is directed to a receiving element for use in a silver diffusion transfer film unit and comprises a transparent support carrying a layer of noble metal silver-precipitating nu~lei in a polymeric binder composition of either hydroxyethyl cellulose (HEC) and gelatin or polyvinyl alcohol and gelatin. The nuclei are present in the range of about 0.1 to 0.4 mgs/ft2 (1.1 to 4.3 mgs/m2); the qelatin at a level of about 0.05 to 1.5 mgs/ft2 t0.54 to 16.1 mgs/m2), and hydroxyethyl cellulose at a level of about 0.1 to 7 mgs/ft2 (1.1 to 75.3 mgs/m2), or polyvinyl alcohol at a level of about 0.1 to 5 mgs/ft2 (1.1 to 53.8 mgs/m2). An excess of hydroxyethyl cellulose or polyvinyl alcohol to gelatin is employed. In a particularly preferred embodiment the support also carries an additive color screen.

lZ~3 -5- `.

DETAILED DESCRIPTION OEI THE INVENTION
The aforementioned copending application Serial No. 269,685 , discloses a nucleating layer with palladium nuclei and a single polymer; at a low coverage of nuclei gelatin is preferred while at a higher level of nuclei hydroxyethyl cellulose is preferred. A large number of other natural and synthetic binder materials are disclosed as suitable, including polyvinyl alcohol.
A combination of hydroxethyl cellulose and gelatin or polyvinyl alcohol and gelatin as the binder for the nuclei has now been found which provides superior photographic results. An excess of hydroxyethyl cellulose or polyvinyl alcohol is employed compared to gelatin.
This is contrary to the disclosure of copending applica-tion Serial No. 269,685 which set a limit on the binder coverage and, in fact, disclosed the lower level of poly-mer range as the preferred level to obtain a more neutral - image tone. The hydroxyethyl cellulose or polyvinyl alcohol and gelatin comprise the sole polymeric binder matrix for the nuclei.
The novel silver-precipitating layers of the present invention employing a binder matrix of HEC and gelatin provide a more stable positive image. It is believed that oxidation of the positive image silver, which may result in silver being relocated behind the wrong filter screen element producing a red effect in the image, is inhibited. The silver image is also less tangible and therefore more suitable for use in a motion picture format where bending and transporting the film unit is common. Significantly greater densities are achieved compared to receiving layers of copending appli-cation Serial No. 269,685, without deleterious effect on speed, range or Dmin.

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The novel silver-precipitating layers of this invention employing a binder matrix of polyvinyl alcohol and gelatin also provide a more stable postiive image, particularly with respect to high humidity conditions, as well as an increase in film speed.
In a preferred embodiment employing hydroxy-ethyl cellulose, a ratio of 5 to 1 hydroxyethyl cellulose to gelatin is employed. In a particularly preferred embodiment, the silver-precipitating layer comprises 0.15 mgs/ft2 (1.6 mgs/m2) palladium, 0.2 mgs/ft2 (2.2 mgs/m2) gelatin and 1.0 mgs/ft2 (10.8 mgs/m2) of hydroxyethyl cellulose. The levels are not critical and can be used throughout the range specified. As levels of HEC are increased, substantially no change in tone is observed. However, at the higher levels, in additive color film units, blue density increases at a greater rate than red and green densities and the silver image tone thus tends to become browner.
In a preferred embodiment employing polyvinyl alcohol, a ratio of 4 to 1 polyvinyl alcohol to gelatin is employed. In a particularly preferred embodiment employing polyvinyl alcohol, the silver-precipitating la~er comprises 0.15 mgs/ft2 (1.6 mgs/m2) of palladium, 0.2 mgs/ft2 (2.2 mgs/m2) of gelatin and 0.8 mgs/ft2 (8.6 mgs/m2) of polyvinyl alcohol.
The noble metals employed in the present inven-tion include silver, gold, palladium and platinum. How-ever, particularly superior results are achieved at the specified coverages with palladium and, for convenience, the invention will be descrihed primarily in terms of this preferred embodiment.
Combinations of noble metals may be used as well as single noble metals. In a preferred embodiment, noble metal salts or complexes may be reacted with reducing metal salts. Suitable compounds include the following:

~l~lZZ3 K2PdC14 PdC12 H2PtC16 AgN03 HAuC14 The following solutions were prepared:
Solution A
Water 3140O4 g.
Glacial Acetic Acid 305 g.
Gelatin (20% solution) 3.6 g.
SnC12- Z H 01.7 g.
Solution B
Water lg6 g Hydroxyethyl cellulose 4.0 g.

Solution C
Water 1400 9.
PdC12 solution (80~6 g HCl 166~6 9 PdC12/ 1. of solution) 28.7 g.

~; -8 Solution A was heated to 81-82C and 330 g. of Solution C added with agitation. Addition was completed within 5 seconds and the solution cooled to 24C with continuing agitation. Water lost through evaporation was replaced. 3.3 g. of 10~ alkyl phenoxypolyoxy ethanol (sold underthe trademark PE 120 by NOPCO Chemical Division of Diamond Shamrock Company) was added. After mixing 5 min., 138 g. of 2-propanol as a coating aid was added. To the combination of Solutions A & C (3472 g.) L0 was added the quantity of Solution B to give the desired HEC/gel ratios.
The utility of such nuclei layers is described below.

A film unit was prepared comprising a trans-parent polyester film base carrying on one surface, an additive color screen of approximately 1500 triplets per inch (590/cm) of red, blue and green filter screen elements in repetitive side-by-side relationship; 328 mgs/ft2 (3530 mgs/m ) polyvinylidine chloride/polyvinyl formal protective overcoat layer; a nucleating layer comprising palladium nuclei with the coverages and polymers desig-nated hereinafter; an interlayer formed by coating 1.9 mgs/ft2 (20.45 mgs/m2) gelatin, 2.3 mgs/ft2 (24.76 mgs/m2) acetic acid and 0.19 mgs/ft2 (2.05 mgs/m2) octylphenoxy polyethoxy ethanol surfactant; a hardened ~elatino silver iodobromo emulsion (0.59~4mean diameter grains) coated at a coverage of about 91 mgs/ft (980 mgs/m2) of gelatin and about 150 mgs/ft2 (1615 mgs/m2) of silver with about 7.18 mgs/ft2 (77.28 mgs/m2) propylene glycol alginate and about 0.73 mgs/ft2 (7.86 mgs/m ) of nonyl phenol polygycol ether (containing 9.5 moles of ethylene oxide) panchromatically sensitized with .

11~12~3 g 5,5' -dimethyl-9-ethyl-3,3'-bis-(3 sulfopropyl) thiacarbocyanine triethyl-ammonium salt (0.53 m~/g Ag);
5,5' -diphenyl-9-ethyl-3,3'-bis(4-sulfobutyl) oxacarbo-cyanine (0.75 mg/gAg); anlydro -5.6-dichloro-1,3-diethyl-

3'-(4"-sulfobutyl)-benzimidazolothiacarbocyanine hydroxide (0.7 mg/g~g); and 3-(3-sulfopropyl)-3'-ethyl-

4,5-benzothia-thiacyanine betaine (1.0 mg/gAg); red, green, green and blue sensitizers respectively; and the following antihalo top coat.

ToP Coat mqs/f t (m~s/m ) Gelatin . 400 (4300) Dow 620~ 204 (2195) (carboxylated styrene/butadiene copolymer latex Dow Chemical Co~, Midland, Michigan) Propylene glycol alginate 25.7 (275) Dioctyl ester of sodium 1.2 (13) sulfosuccinate Benzimidazole-2-thiol gold Au+l complex 5 (as gold) (54) Daxad-ll*(polymerized sodium salts 0.38 (4.1) of alkyl naphthalene sulfonic acid) Manufactured by W.R. Grace & CoO
Cambridge J MA
Pyridinium bis-1,5 5.6 (60) (1,3-diethyl-2-thio1-5-barbituric acid) pentamethine oxanol 4-(2-chloro-4-dimethylamino 7 (75) benzaldehyde)-l-(p-phenyl carboxylic acid)-3-methyl pyrazolone-5 * Trade Mark `:~

Processinq Composition A
heiqht %
Sodium hydroxide 9.4 hydroxyethyl cellulose 0.7 (sold by HercuLes, Inc., Wilmington, Delaware under the tradename Natrosol 250HF*) Tetramethyl reductic acid 9.0 Potassium bromide 0.6 Sodium sulfite 0.8 2-methylthiomethyl-4,6-dihydroxypyrimidine 9.0 4-aminopyrazolo-[3,4d]-pyrimidine 0.02 N-benzyl-a-picolinium bromide (50% solution) 2.9 Water 67.6 Trade Mark Processing Composition B comprised Processinq Composition A with about 3.3% by weight of sodium tetra-borate~lO H2O.
Film units prepared according to the above pro-cedure were given a 16 mcs exposure with a Xenon sensi-tometer and processed with mechanical rollers with an 0.8 mil (0.02mm) gap disposing the processing composition between the top coat and a polyethylene terephthalate cover sheet. The film unit was held in the dark for one minute and then the cover sheet was removed, retaininq the rest of the film unit together and then drying.
The hydroxyethyl cellulose polymers employed in the present invention are sold under the trade name NATROSOL by Hercules Inc., Wilmington, Delaware. The numeral designates the degree of substitution and the letters indicate the relative viscosity type, i.e., HH = highest and L = lowest.
A - Natrosol 250 HHP
B - Natrosol 250 L
C - Natrosol 250 H4R
D - Natrosol 250 MH
E - Natrosol 250 HHR
More details regarding the Natrosol products may be found in the Hercules Natrosol Products Bulletin 25 855C 7/69, provided by Hercules, Inc., Wilmington, Dela-ware The following ta~les set ~or~h spectrll ~ata from film units of the present invention employing in the receiving layer 0.2 mgs/ft2 (2.15 mqs/m2) of gelatin;
30 0.15 mgs/ft2 (l.61 mgs/m2) Pd and the designated coverage of HEC. In Table 2 the silver coverage in the emulsion was ll0 mgs/ft2 (1180 mgs/m2) and the average mean diameter of the grains was 0.59,~. Control A contained no HEC and the nuclei were formed under a blanket of nitrogen, excluding air. Control B contained no ~IEC and the nuclei were prepared according to the procedure of Example 8 in 11~1;~2~

copending Canadian application Serial No. 324,893*. The nuclei in Table 2 were also made according to the procedure of Example 8 in copending application Serial No. 324,893.
The spectral data was obtained by reading the neutral column to red, green and blue light in an automatically recording densitometer.

*~see also United States Patent 4,204,869.

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In the above tables the increase in density obtained in film units of the present invention is shown.
- It will also be seen that advantageous results, in the form of increased densities can be obtained over a rela-tively wide range and that the viscosity range of the particular HEC employed is not critical.

Example 1 was repeated, substituting in Solution B 4.0g of polyvinyl alcohol (Elvanol 72-5~, sold by E. I. duPont de Nemours & Co., Wilmington, Delaware) for the 4.0g of hydroxyethyl cellulose.
The utility of such nuclei layers is described below.

A film unit was prepared in the manner described in Example 2, employing a nucleating layer comprising palladium nuclei with the coverages and polymers desiqnated hereinafter.
Processing composition A of Example 2 was employed.
Film units prepared according to the above pro-cedure were given a 16 mcs exposure with a Xenon sensi-tometer and processed with mechanical rollers with an 8 mil. gap disposing the processing composition between the top coat and a polyethylene terephthalate cover sheet.
The film unit was held in the dark for l minute and then the cover sheet was removed, retaining the rest of the film unit together and then air drying.

* Trade Mark 11~12Z3 : TAsLE 3 Receiving Layer Coverages (mgs/ft ) Pd qelatin polvvinyl alcohol PVA/~
ratio 0.15 0.2 0.4 2/1 0.15 0.2 o.~ 4/1 0~15 0.2 1.5 8/1 0.15 0.2 3u8 20/1 llZ23 Visual examination of the projected image showed substantial elimination of the type of imaqe degradation which was found in film units which did not employ the receiving layer of the present invention.
The following tables set forth spectral data from film units of the present invention employing as receiving layer coverages a 4/1 polyvinyl alcohol/
gelatin ratio. In Table 2 the silver coverage in the emulsion is 150 mgs/ft2 and the average mean diameter of the grains is 0.73~. In Table 3 the silver cover-- age in the emulsion is 110 mgs/ft2 and the average mean diameter of the grains is 0.59~. The controls shown in Tables 4 and 5 contain no polyvinyl alcohol.
The spectral data was obtained by reading the neutral column to red, green and blue light in an automatically recording densitometer. The 0.8 green exposure (speed) represents the wedge density that gives a green density of 0.8 plus Dmin and is a measure of speed.
The source of the different polyvinyl alcohols is set forth below.
A Elvanol 72 - 60* E.I. DuPont de Nemours, & Co., Wilmington, Delaware B Gelvatol 1 - 90* Monsanto Chemical Company St. Louis, Missouri - C Vinol 350* Air Products and Chemicals Inc., Wayne, Indiana * Trade Mark ?

, max/Dmin 0 . 8 Green Type Exposure ~Speed) PVA
Red Green Blue 1.98/0.53 2.04/0.53 2 01/0.51 1.99 --1.78/0.53 1.81/0.48 1.79/0.49 2.21 A
1~ 98/0.53 2.03/0.52 1.99/0.52 2.15 B
1 . 95/0 . 50 1 . 95/0 .4;~ 1. 95/0 .48 2 . 19 C

~l~lZ,;~3 DmaX/Dmin 0.8 Green T~pe l~ed Green Blue Exposure (Speed) PVA_ 3.26io.45 3.23/0.4S 3.01/0~42 1.77 __ 3.05/0.39 3,09/0.42 3,00/0.41 1082 A
3.15/0.40 3 O 15/0.39 3.08/0.39 1 ~ 84 B
3,.08/0.43 ~.13/0.45 3.02/0.42 1.~ C

~12;~3 From the above it can be seen that significantly increased film speed is obtained.
While the present invention is defined primarily in terms of additive color systems, it should be understood that the novel image-receiving elements of the present inventions are also suitable for use in black and white silver diffusion transfer systems.
The support employed in the present invention : is not critical. The support or film base employed may comprise any of the various types of transparent rigid or flexible supports, for example, glass, polymeric films of both the synthetic type and those derived from naturally occurring products, etc.
The additive color screen employed in the present invention may be formed by techniques well known in the art, e.g. ! by sequentially printing the requisite filter patterns by photomechanical methods. An additive color screen comprises an array of sets of colored areas or filter elements, usually from two to four different colors, each of said sets of colored areas being capable of trans-mitting visible light within a color filter elements transmits light within one of the so-called primary wave-lengths ranges, i.e., red, green and blue. The prepara-tion of color screens is disclosed, for example, in U.S.
Patent Nos. 3,019,124; 3,032,008; and 3,284,208.

Claims (9)

1. An image-receiving element for use in a photographic silver diffusion transfer process which com-prises a transparent support carrying a layer comprising noble metal silver-precipitating nuclei, in a polymeric binder composition of gelatin and hydroxyethyl cellulose or polyvinyl alcohol and gelatin; wherein said nuclei are present in a level of about 0.1 - 0.4 mgs/ft2 (1.1-4.3 mgs/m2); and said hydroxyethyl cellulose at a level of about 0.1 to 7 mgs/ft2 or said polyvinyl alcohol at a level of about 0.1 to 5 mgs/ft2 (1.1-53.8 mgs/m2); and said hydroxyethyl cellulose or polyvinyl alcohol is present in an excess over said gelatin.

2. The element of claim 1 wherein said noble metal is palladium.

3. The element of claim 2 wherein said palladium is obtained by the reduction of a salt or complex.

4. The element of claim 1 including an anti-halation layer.

5. The element as defined in claim 1 which includes an additive color screen.

6. An image-receiving element for use in an additive color photographic diffusion transfer process which comprises a transparent support carrying an additive color screen and a layer comprising palladium metal silver-precipitating nuclei, gelatin and hydroxyethyl cellulose wherein said nuclei are present at a level of about 0.15 mgs/ft2 (1.6 mgs/m2); said gelatin is present at a level of about 0.20 mgs/ft2 (2.2 mgs/m2) and said hydroxyethyl cellulose is present at a level of about 1.0 mgs/ft2 (10.8 mgs/m2) and said palladium nuclei are formed by the reduction of palladous chloride with stannous chloride.

7. An image-receiving element for use in an additive color photographic diffusion transfer process which comprises a transparent support carrying an additive color screen and a layer comprising palladium metal silver-precipitating nuclei, gelatin and polyvinyl alcohol wherein said nuclei are present at a level of about 0.15 mgs/ft2 (1.g mgs/
m2); said gelatin is present at a level of about 0.2 mgs/ft2 (2.2 mgs/m2) and aaid polyvinyl alcohol is present at a level of about 0.8 mgs/ft2 (8.6 mgs/m2) and said palladium nuclei are formed by the reduction of palladous chloride with stannous chloride.

8. The element of claim 6 or 7 which includes a photo-graphic processing composition containing sodium tetraborate decahydrate.

9. An image-receiving element of claim 6 or 7 including an antihalation layer.