US3740220A

US3740220A - Photographic material

Info

Publication number: US3740220A
Application number: US00882737A
Authority: US
Inventors: Haes L De; E Hofman; H Gevers
Original assignee: Agfa Gevaert AG
Current assignee: Agfa Gevaert NV; Agfa Gevaert AG
Priority date: 1968-12-06
Filing date: 1969-12-05
Publication date: 1973-06-19
Anticipated expiration: 1990-06-19
Also published as: DE1961030C3; DE1961030A1; DE1961030B2; FR2025524A1; BE742284A; GB1297115A

Abstract

A COMPOSITE INTEGRAL LIGHT-SENSITIVE PHOTOGRAPHIC MATERIAL FOR FORMING COPIES BY MEANS OF THE DIFFUSION TRANSFER PROCESS COMPRISING IN SUCCESSIVE ORDER A TRANSPARENT FLEXIBLE SUPPORT SHEET AND IMAGE-RECEIVING LAYER COMPRISING DEVELOPMENT NUCLEI, A PIGMENT LAYER CONTAINING AN OPAQUE WHITE OR COLORED PIGMENT DISPERSED IN A HYDROPHILIC COLLOID BINDER, WHEREIN THE PIGMENT AND THE BINDER OF THE PIGMENT PARTICLES ARE PRESENT IN AN AMOUNT OF FROM 7 TO 25 G. PER SQ. M. AND OF FROM 0.5 TO 4 G. SQ. M., RESPECTIVELY, AND A LIGHT-SENSITIVE SILVER HALIDE EMULSION LAYER, THE MAXIMUM DEVELOPED REFLEX DENSITY OF WHICH IS EQUAL TO OR LOWER THAN 0.8. A PHOTOGRAPHIC METHOD USING SUCH MATERIAL IS ALSO DISCLOSED. THE DEVELOPED MATERIAL HAS A POSITIVE IMAGES IN THE IMAGE-RECEIVING LAYER WHICH IS VISIBLE DIRECTLY THROUGH THE TRANSPARENT SUPPORT SHEET, TOGETHER WITH A NEGATIVE IMAGE IN THE EMULSION LAYER WHICH IS HIDDEN FROM THE POSITIVE IMAGE BY MEANS OF THE INTERVENING PIGMENT LAYER SO THAT THE MATERIAL CAN BE EXPOSED, DEVELOPED AND VIEWED IN THE FORM OF AN INTEGRAL ASSEMBLY WITHOUT SEPARATION OF THE PARTS THEREOF.

Description

United States Patent 3,740,220 PHOTOGRAPHIC MATERIAL Louis Maria De Haes, Edegem, Emiel Alexander Hofman, Mortsel, and Hugo Karel Gevers, Edegem, Belgium, assignors to Agfa-Gevaert, Mortsel, Belgium No Drawing. Filed Dec. 5, 1969, Ser. No. 882,737 Claims priority, application Great Britain, Dec. 6, 1968, 58,152/ 68 Int. Cl. G03c 5/54 US. CI. 96-29 R 12 Claims ABSTRACT OF THE DISCLOSURE A composite integral light-sensitive photographic material for forming copies by means of the diflusion transfer process comprising in successive order a transparent flexible support sheet and image-receiving layer comprising development nuclei, a pigment layer containing an opaque white or colored pigment dispersed in a hydrophilic colloid binder, wherein the pigment and the binder of the pigment particles are present in amount of from 7 to 25 g. per sq. In. and of from 0.5 to 4 g. sq. m., respectively, and a. light-sensitive silver halide emulsion layer, the maximum developed reflex density of which is equal to or lower than 0.8. A photographic method using such material is also disclosed. The developed material has a positive image in the image-receiving layer which is visible directly through the transparent support sheet, together with a negative image in the emulsion layer which is hidden from the positive image by means of the intervening pigment layer so that the material can be exposed, developed and viewed in the form of an integral assembly without separation of the parts thereof.

The present invention relates to a photographic lightsensitive composite sheet material and to a method of producing images according to the silver complex diffusion transfer process wherein such material is used.

The photographic light-sensitive composite sheet material according to the present invention successively comprises a flexible transparent support sheet, an image-receiving layer comprising substances for promoting the conversion of complexed diffusing silver halide to form a visible image (these substances are further on called development nuclei), a pigment layer containing an opaque white or coloured pigment and a hydrophilic colloid binder, wherein the pigment and the binder of the pigment particles are present in amounts of from 7 to 25 g. sq. m. and of from 0.5 to 4 g. per sq. m. respectively, and a light-sensitive silver halide emulsion layer, the maximum developed reflex density of which is equal to or lower than 0.8.

The present invention also relates to a method of producing a photographic diflusion transfer copy comprising the steps of image-wise exposing the light-sensitive silver halide emulsion layer of a photographic composite sheet material as described above and treating this material in the presence of a developing compound, a complexing agent for silver halide and an alkaline substance with an aqueous liquid. The diffusion transfer copy thus obtained is viewed through the transparent support and the low density negative image is then completely screened from the eye of the pigment layer. At the emulsion side of the copy only a very faint and not disturbing negative image is visible.

When a silver halide emulsion layer is applied as described above, the use of high amounts of pigment particles in the pigment layer can be avoided, so that the diffusion of the complexed silver halide from the nonexposed areas of the emulsion layer is promoted. A diifusion transfer image showing a sufliciently high maximum 'ice density, mostly amounting to about 1.5, can be produced thereby in spite of the nature of the silver halide emulsion layer.

The requirements of amixmum. developed reflex density of 0.8 of the silver halide emulsion layer may be complied with by applying the liquid silver halide emulsion in such a proportion that only a restricted amount of silver halide particles is present per surface unit of the light-sensitive material. According to another technique a considerable amount of pigment particles and/or screening dyes may be incorporated int-o the silver halide emulsion layer. According to a preferred embodiment, however, silver halide emulsions are used, which have the inherent property of being developable only to a low maximum density after exposure. This may be achieved by producing rather large silver halide grains. Two or more techniques for producing a silver halide emulsion layer complying with the requirements of the present invention may be combined.

Any type of silver halide is suitable for preparing the emulsion layer, provided the silver halide grains are capable of being developed and complexated in the exposed and non-exposed areas respectively with the rapidity required in diffusion transfer processess. The silver halide emulsion used may be a low-sensitive or a high-sensitive emulsion and may have either a steep gradation for the production of a line copy or a rather soft gradation for the production of a continuous tone image. For the reproduction of a line original often a low-sensitive silver chloride emulsion having a steep gradation is used, Whereas for the reproduction of a continuous tone original preferably a silver bromo-iodide emulsion having a soft gradation is used. Provided the sensitivity of the silver halide emulsion is sufliciently high, the photographic composite sheet material according to the present invention is especially suitable for making aerial photographs.

The pigment layer preferably contains white pigment particles. Barium sulphate and titanium dioxide are especially suitable for this purpose. The size of the pigment particles is of no great importance for the purpose of the present invention. Coarse as well as extremely fine grains are suited. The particle size: mostly is comprised between 0.05 and 0.5,u. In general, optimal results are obtained with an amount of 10 to 20 g. of pigment and of 1 to 3 g. of hydrophilic colloid per sq. m. Gelatin is often used as the hydrophilic colloid binder of the pigment particles. However, other hydrophilic colloids and mixtures of two or more types of hydrophilic colloids may be used. So, a mixture of a protein, e.g. gelatin, and a hydrophilic colloid, which in the alkaline medium wherein the production of the diffusion transfer image takes place hardens said protein, is especially suited as a binder of the pigment particles. Hydrophilic colloids of this type are comprised in the class of compounds designated as latent hardeners of said proteins. Suitable hydrophilic colloids of this type are addition products of high molecular weight hydroxyl group-containing compounds with acrolein, described in the United States patent specification 3,382,077 and especially water-soluble hydroxyalkyl esters of alginic acid, particularly propylene glycol esters of alginic acid, described in the United States patent specification 3,378,373.

The image-receiving layer present between the pigment layer and the transparent support sheet may be constituted by development nuclei applied by vacuum coating but preferably is a hydrophilic colloid layer containing development nuclei. The hydrophilic colloid binder is preferably gelatin, although the gelatin may be replaced at least partly by other hydrophlic colloids. The development nuclei may be small metal particles but preferably are sulphides of heavy metals such as the sulphides of antimony, bismuth, cadmium, cobalt, lead, nickel, silver,

and zinc. Of course, other types of development nuclei can be used. Further details on the composition and the thickness of the image-receiving layer as well as on the concentration of the development nuclei are superfluous. In this respect, reference is made to the very extensive art literature, including the patent literature. The imagereceiving layer may be applied, directly or indirectly by means of a suitable subbing layer, to the flexible transparent support sheet.

For the purpose of the present invention the support has to be sufiiciently transparent to permit the diffusion transfer image produced in the image-receiving layer to be viewed through the support. So, a paper sheet that has been made transparent can be used. An especially suitable paper support is the so-called pergamin paper that owes its transparency to hydration and mechanical treatment at the preparation stage. Preferably, however, the transparent support sheet of the composite sheet material according to the present invention is a hydrophobic synthetic film support having a rather small thickness that is preferably comprised between about 0.05 and 0.2 mm. Suitable hydrophobic synthetic polymers are cellulose esters, e.g. cellulose triacetate, polyesters e.g. polyethylene terephthalate, polystyrene, and copoly(vinyl chloride/vinyl acetate).

The photographic material according to the present invention may comprise all kinds of additional layers, e.g. an antihalation layer, a top layer for protecting the silver halide emulsion layer against abrasion, or for completely screening the negative image from the eye, one or more intermediate layers to improve the adherence between two layers, or to facilitate the diffusion of some substances from one layer to the other, an antistatic layer, which is preferably applied to the free rear side of a hydrophobic film support, etc.

According to a preferred embodiment the rear side of the transparent support is provided with a matting layer, e.g. a gelatin layer containing silica particles. Such a layer exerts an antistatic and anticurling effect on the photographic material, gives the diifusion transfer copy produced a more pleasant appearance, and allows to write on the material more easily.

The layers of the photographic sheet material may be applied according to Whatever technique known in the art, e.g. by dip-coating, reverse roll-coating, or by spraycoating.

The photographic composite sheet material may contain all kind of ingredients, e.g. sensitizers, stabilizers, plasticizers, hardeners including latent hardeners, e.g. the hydrophilic colloid binders referred to above, developing agents, preservatives for developing agents complexing agents for silver halide, alkali-releasing substances, imagetone improvers, anti-silver sludge agents, anti-yellowing agents, anti-staining agents, alkali-consuming substances, dispersing and wetting agents etc. The use of these ingredients in photographic materials for producing diffusion transfer copies is generally known in the art. For more details thereon reference is made to the very extensive art literature including the patent literature.

The incorporation of developing substances, especially of hydroquinone and a S-pyrazolidinone developing agent, into at least one layer of the composite sheet material is a preferred embodiment of the present invention. In many cases the total amount of developing substances is incorporated into the photographic material, so that the processing liquid is reduced to a mere alkaline liquid that is substantially free from developing agents, and consequently has better keeping properties.

In carrying out the method of the present invention the silver halide emulsion layer of the photographic composite sheet material is image-wise exposed to visible light or to a high energetic radiation beam, e.g. an electron beam, X-rays, 'y-rays, light produced by a laser etc. The image-wise exposure is preferably carried out reflectographically by placing the original in contact with the emulsion side of the composite sheet material, and transmitting the exposing rays through said material. However, exposure in a camera is also possible.

For producing the diffusion transfer image the composite sheet material is then wetted with an aqueous processing liquid in the presence of developing agents, a complexing agent for silver halide, e.g. sodium thiosulphate, and an alkaline substance. The alkaline substance and the complexing agent for silver halide are preferably provided in the aqueous liquid. The developing compound(s) for silver halide, on the contrary, (is) are preferably at least partially and even wholly present in the photographic material as described above. The processing liquid preferably has a rather low viscosity and is a mere aqueous soluion. It may be applied according to whatever technique usual in the art, e.g. by dipping the composite sheet material in it, by means of a licking roller etc. It may contain all kinds of additional ingredients, e.g. heavy metal ions-sequestering agents, and anti-silver sludge agents, stabilizers, image-tone improvers, wetting agents, etc.

After a very short processing time, an excellent diffusion transfer image becomes visible through the support. The following example illustrates the present invention.

EXAMPLE Both sides of a cellulose triacetate film support having a thickness of 0.1 mm. were coated with a gelatin subbing layer.

One side of the resulting subbed film support was provided with a mat layer from the following coating composition in a ratio of 10 sq.m./litre:

Water ml 500 Silica g 140 Gelatin g 70 Water up to 1000 ml.

The other side of the subbed film support was coated successively with the following layers:

An image-receiving layer obtained by applying the following coating composition at a ratio of 30 sq.m./litre:

Water ml 820 Gelatin g 60 Dispersion of silver sulphide in an aqueous solution of gelatin (0.2% of silver sulphide and 11.6%

of gelatin) ml 30 A 1% solution of l-phenyl-5-mercaptotetrazole in ethanol ml 1 1-pheny1-3-pyrazolidinone g 5 12.5% aqueous solution of saponin ml 30 Water to 1000 ml.

A pigment layer obtained by applying the following coating composition at a ratio of 10 sq. m./litre:

Water ml 603 Titanium dioxide g Gelatin g 4.8 Propylene glycol ester of alginic acid g 17.2 12.5% aqueous solution of saponin ml v 25.8 20% aqueous solution formaldehyde ml 4.3

Water to 1000 1111.

diffusion transfer copies, this apparatus containing the following alkaline processing liquid:

Water ml 1000 Sodium phosphate g 75 Anhydrous sodium sulphite g-- 40 Anhydrous sodium thiosulphate g A high quality diffusion transfer image became visible through the cellulose triacetate support. The maximum reflex density of this image amounted to 1.5. The maximum reflex density of the negative image at the emulsion side amounted to 0.5.

The negative image was not visible at the side of the support because it was screened from view by the pigment layer.

We claim:

1. A composite integral light-sensitive diffusion transfer photographic sheet material for copying originals comprising in successive order a flexible transparent support sheet, and image-receiving layer comprising development nuclei, a pigment layer containing an opaque white or colored pigment dispersed in an exterior hydrophilic colloid binder, wherein the pigment and the binder of the pigment particles are present in amounts of from 7 to g. per sq. m. and of from 0.5 to 4 g. per sq. m. respectively, and a light-sensitive silver halide emulsion layer, the maximum developed reflex density of which is equal to or lower than 0.8.

2. A photographic material according to claim 1, wherein the image receiving layer is a gelatin layer comprising heavy metal sulphide development nuclei.

3. A photographic material according to claim 1, wherein the pigment particle sof the pigment layer are barium sulphate and/or titanium dioxide pigment particles.

4. A photographic material according to claim 1, wherein the binder of the pigment layer comprises gelatin.

5. A photographic material according to claim 1, wherein the binder of the pigment layer comprises gelatin and a hydrophilic colloid being a latent hardener for gelatin.

6. A photographic material according to claim 5, wherein said hydrophilic colloid being a latent hardener for gelatin is a propylene glycol ester of alginic acid.

7. A photographic material according to claim 1, wherein the pigment layer contains an amount of pigment particles of from 10 to 20 g. per sq. rn. and an amount of hydrophilic colloid binder of from 1 to 3 g. per sq. m.

8. A photographic material according to claim 1, wherein the rear side of the photographic material is provided with a matting layer.

9. A photographic material according to claim 1, wherein the composite sheet material comprises a developing agent.

10. A photographic material according to claim 9, wherein the composite sheet material comprises hydroquinone and/or a 3-pyrazolidinone: developing agent.

11. In a method of reproducing an original by the photographic diifusion transfer process comprising the steps of image-wise exposing a composite integral photographic light-sensitive sheet material and subsequently treating this material in the presence of photographic developing agent, a complexing agent for silver halide, and an alkaline substance, with an aqueous processing liquid, the improvement wherein said photographic lightsensitive composite sheet material comprises in successive order a flexible transparent support sheet, an imagereeciving layer comprising development nuclei, a pigment layer containing an opaque white or colored pigment dispersed in a hydrophilic colloid binder, wherein the pigment and the binder of the pigment particles are present in amounts of from 7 to 25 gpper sq. m. and of from 0.5 to 4 g. per sq. m. respectively, and an exterior light-sensitive silver halide emulsion layer, the maximum developed reflex density of which is equal to or lower than 0.8, and said composite material is exposed reflectographically through said transparent support sheet while said original is disposed in direct contact with said emulsion layer, whereby the copy of the original when viewed through said transparent support sheet is a right reading positive of said original.

12. A method according to claim 11, wherein the total amount of the photographic developing agent is present in the photographic composite sheet material and the aqueous processing liquid is an alkaline liquid substantially free of any developing agent.

References Cited UNITED STATES PATENTS 2,692,830 10/1954 Land 96-29 R 2,563,342 8/1951 Land 96-29 X 3,335,007 8/1967 DeHaes 96-29 3,245,791 4/1966 Ryan 96-29 3,053,745 9/1962 Levinos 9629 X 3,042,514 7/ 1962 Roth 9629 3,021,214 2/1962 Murphy et a1. 9629 NORMAN G. TORCHIN, Primary Examiner I. L. GOODROW, Assistant Examiner U.S. Cl. X.R. 9676 C, 47

, Attesting Officer Dated June 19, 1973 Patent No 3,740 ,220

lnventofls) Louis Maria DE HAES et ,1

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 5, Claire 1, line 20, cha nge "and" to an line 22, change "an exterior" to a line 26 oh ang e "and e" to and an exterior i Q Signed arid sealed this 22nd day of January 19714..

(SEAL) At test:

EDWARD 1V1}. FLE'TCHEEJE, RENE D. TEGTMEYER Acting Commissioner of Patent