DE1157480B - Image receiving material for the silver salt diffusion transfer process - Google Patents

Description

The principle of the halogen silver diffusion transfer method is described in British Patents 614155 and 654 630, and in US Pat German patent specification 887 733. According to this process, the halogen silver emulsion layer is diffused silver complex salt transferred after the image receiving layer by the action of the in the image receiving layer, also called the seed layer, present development germs developed.

With regard to the silver deposition in the picture ίο receiving layer can be said that a high density by a rapid development the silver complexes can be promoted, so that these complex salts do not find the opportunity to spread laterally in the germinal layer. This lateral spread would build up one less cause dense and more diffuse diffusion transfer image.

The rate of silver deposition and, consequently, the density of the diffusion transfer image are strongly dependent on the nature and concentration of the development nuclei used.

Regardless of this, the deposition of metallic silver can be carried out according to that described in US Pat 2 698 237 can be accelerated by adding colloidal silica to the seed layer incorporated.

It has now been found that by adding colloidal silica to a water-permeable Cover layer of the image receiving material, the reduction of the diffusing silver complex salts, as it were is initiated so that a faster and more complete reduction of the silver complexes in the image receiving material is achieved. This way, a sharp and dense image is obtained, which is likely the fact that the initiating effect of the colloidal silica produces a vertical Silver germ trace is formed in the water-permeable top layer. In addition, one poses when using a material according to the invention, a favorable matting effect is found.

Any water-permeable colloid layer can be used as the water-permeable colloid layer, which the diffusing halogen silver complex salts penetrate into the image-receiving layer and after the construction of the diffusion transfer image, a good separation of the photosensitive material made possible by the image receiving material. Suitable top layers are, for. B. described in the French patents 1,304,279 and 1304,280.

As the colloidal silica, dispersions of hydrogenated silica can be used, e.g. Legs Image receiving material

for the silver salt diffusion transfer

procedure

Applicant:

Gevaert Photo-Products NV,
Mortsel, Antwerp (Belgium)

Representative: Dr. W. Muller-Bore

and Dipl.-Ing. H. Gralfs, patent attorneys,

Braunschweig, Am Bürgerpark 8

Claimed priority;
Belgium of October 4, 1961 (No. 41 010)

Dr.-Chem. Louis Maria de Haes,

Edegem (Belgium),
has been named as the inventor

3O% aqueous dispersion of silica and a 30% aqueous dispersion of silica particles with an average size of 0.025 μ. Depending on These silica compositions can be used in the casting composition to achieve the desired matting effect the water-permeable layer mostly in an amount of 5 to 50 g per liter. More information about the thickness of a water-permeable top layer can be found in the relevant patents, inter alia in the two French patents cited above.

The image receiving material may consist of a support or a support and one attached thereon Colloid layer that contains development nuclei for complexed halogen silver. There come both physical and chemical development nuclei are considered.

Development nuclei suitable for producing the silver-containing image in the image-receiving layer are the sulfides of heavy metals such as antimony, bismuth, cadmium, cobalt, nickel, iron, tin, Thallium, copper, lead, silver and zinc. The selenides, polysulfides, polyselenides, mercaptans, tin (II) halides, Heavy metals or their salts as well as veiled halogen silver are also very suitable. Lead sulfide and zinc sulfide as well as theirs

309 748/285

complexed salts, alone or mixed with thioacetamide, dithiobiuret and dithiooxamide, are special Interesting. As heavy metals, silver, gold, platinum, palladium and mercury are preferred in colloidal form, to be mentioned. Of these, the precious metals are the most effective.

These development nuclei can be incorporated into the carrier material itself or can be added to a suitable carrier, such as paper, from solutions or dispersions of such development nuclei in a colloidal medium such as gelatin.

The image-receiving layer and / or the water-permeable top layer can also contain other ingredients such as developing substances, complexing agents for halogen silver, compounds for preventing contain yellowing, plasticizers, image tone influencers, etc.

Suitable image tone influencers are described in Belgian patent specification 605 802, the French U.S. Patent Nos. 1,305,068 and 1,140,526; and U.S. Patent 2,699,393.

Particularly favorable results have been achieved if picture tone influencers are used according to the latter Patent used in combination with metal sulfide seeds with the exception of silver sulfide seeds.

To carry out the method according to the invention any halide silver emulsion is suitable, its exposed silver salt during the diffusion transfer process Developed sufficiently quickly and their unexposed silver salt also sufficient is quickly complexed. Chlorine silver emulsions are preferably used for this purpose, the specific May contain silver bromide or silver iodine or which contain certain substances in order to achieve the desired emulsion characteristics may be added. One can get into the photosensitive material also incorporate certain substances that play a role in diffusion transfer image formation to play.

As the developing liquid, one commonly used in the silver salt diffusion transfer method Used developer liquid: it contains, among other things, the substances necessary for development of exposed silver halide such as hydroquinone and 1-phenyl-3-pyrazolidone, a complex salt forming agent for halogen silver etc. Some of these substances can be wholly or partly the light-sensitive Material or the image receiving material.

Details about the diffusion transfer process, the composition of the halogen silver emulsion layers, the image receiving material, the baths, the exposure and development equipment can be found in "Progress in Photography", Vol. I, 1940-1950, pp. 76, 77 and 140; Vol. II, 1951-1954, pp. 156,157; Vol. III, 1955-1958, pp. 24 to 36, and in the patent literature mentioned there.

The following examples illustrate the invention.

example 1

A paper support of 90 g per square meter is provided with an image-receiving layer composed of one Suspension of the following composition:

Water 100 cm ³

Sodium thiosulfate 1.2 g

Gelatin 8 g

10% aqueous solution of
Sodium sulfide

10% solution of cobalt (II) -

nitrate

Previous solution of 1-phenyl-5-mercapto ~ l, 2,3,4-tetrazole in ethanol

0.2 g 0.8 cm ³

learn ³

After drying, a second ίο layer of the following suspension is applied:

Water 100 cm ³

Carboxymethylcellulose sodium salt 0.75 g 10 Voige aqueous solution of

Potassium chromium sulfate q, 20 g

SO'o / oige aqueous suspension of

Silica 10 cm ³

The image-receiving material obtained is dried and, together with an image-wise exposed light-sensitive material, the halide silver emulsion layer of which contains 1.3 g of chlorine silver per square meter, passed through a developing device for diffusion transfer which is filled with a developing solution of the following composition: 25

Sodium Hydroxide Hg

Anhydrous sodium sulfide 100 g

Potassium bromide 1.5 g

Hydroquinone 9 g

" ₀ 1-phenyl-3-pyrazolidone 1.5 g

Water up to 1000 cm ³

Then you press the image-receiving layer and the photosensitive layer between the Rubber rollers of the developing device together. The image receiving material is separated after about 20 seconds and the photosensitive material from each other. One receives in the receiving layer a sharp image with good coverage and neutral image tone.

Example 2

A paper support of 90 g per square meter is provided with an image-receiving layer composed of one Suspension of the following composition:

Water 898 cm ³

Gelatin 80 g

Sodium thiosulphate 12 g

10% aqueous sodium sulfide solution 2 cm ^{3 10% aqueous solution of cobalt}

nitrate 8 cm ³

After drying, apply a second layer of the following composition:

Water 100 cm ³

Carboxymethyl cellulose sodium salt 0.75 g 1% solution of 1-phenyl

5-mercapto-1,2,3,4-tetrazole in

Ethanol 5 cm ³

30% aqueous dispersion of

Silica 10 cm ³

The image receiving material obtained is dried and brought together with an image-wise exposed one light-sensitive material, the halogen silver layer of which contains 1.3 g of chlorine silver per square meter, through the developing bath of Example 1.

Then you press the image-receiving layer and the photosensitive layer between the

Rubber rollers of the developing device together. The image receiving material is separated after about 20 seconds and the photosensitive material from each other. One receives in the receiving layer a sharp image with good coverage and neutral image tone.

Claims (3)

PATENT CLAIMS: 1. Image receiving material for the silver salt diffusion transfer process, according to which a direct positive image is produced by developing an exposed halogen silver emulsion layer and imagewise transferring the undeveloped halogen silver present as complex salt into an image receiving layer containing development nuclei, characterized in that a water-permeable cover layer is arranged on the image receiving layer, the colloidal silica contains. 2. Image receiving material according to claim 1, characterized in that the image receiving layer contains an image tone influencer. 3. Process for making direct positive images by the silver salt diffusion transfer process, characterized in that a material according to one of Claims 1 and 2 is used as the image receiving material. ® 309 748/285 11.63