US3694209A - Process for the development of exposed photographic material containing silver halide - Google Patents

Abstract

A PROCESS FOR RAPID DEVELOPING OF EXPOSED PHOTOGRAPHIC SILVER HALIDE MATERIAL, ESPECIALLY X-RAY FIBERS IS PROVIDED. THE PROCESS CONSISTS IN FIRST TREATING THE MATERIAL WITH A STRONG ALKALI METAL HYDROXIDE SOLUTION AND THEN WITH THE DEVELOPER SOLUTION AND AFTERWARDS CARRYING OUT THE PROCESSING STEPS REQUIRED FOR FINISHING THE PHOTOGRAPH. THE DEVELOPING BATH MAY BE FOLLOWED BY A SECOND ALKALINE BATH. THIS PROCESS MAKES IT POSSIBLE TO OBTAIN STABLE IMMEDIATELY VISIBLE PICTURE SHORTLY, E.G. 14 SECONDS, AFTER EXPOSURE.

Description

United States Patent ffi cer 3,694,209 Patented Sept. 26, 1972 3,694,209 PROCESS FOR TI-E DEVELOPNENT F EXPOSED PHOTOGRAPHIC MATERIAL CONTAINING SIL- VER HALIDE Georg Schwienbacher, Zurich, Switzerland, assignor t0 Ciba-Geigy AG, Basel, Switzerland 7 No Drawing. Filed Mar. 9, 1970, Ser. No. 17,967 Claims priority, application Switzerland, Mar. 14, 1969, 3,879/ 69 Int. Cl. G03c 5/26 US. C]. 96-50 8 Claims ABSTRACT OF THE DISCLOSURE A process for rapid developing of exposed photographic silver halide material, especially X-ray fibers is provided. The process consists in first treating the material with a strong alkali metal hydroxide solution and then with the developer solution and afterwards carrying out the processing steps required for finishing the photograph. The developing bath may be followed by a second alkaline bath. This process makes it possible to obtain stable immediately visible picture shortly, e.g. 14 seconds, after exposure.

The present invention relates to the development of exposed photographic material containing silver halide.

In various photographic applications there is a demand for the picture to be visible as soon as possible after it has been taken and as a rule the picture should also have good stability, that is to say it should not undergo changes in storage and certainly not fade altogether. The process of the present invention meets this demand especially with regard to X-ray films, irrespective of whether they are used in medicine or in technology. Especially with commercial X-ray films, which in most cases are coated on both sides with layers having a high content of silver halide, the production of immediately visible images having a good stability involves considerable difiiculties.

The present invention is based on the observation that exposed photographic material containing silver halide can be developed very rapidly to stable images by (I) treating the material for at least /2 second at a temperature within the range of from to 80 C. wiah an aqueous solution containing per litre from to 250 g. of an alkali metal hydroxide and then (2) treating the so-treated material for at least 0.1 second with an aqueous solution containing per litre from 20 to 50 g. of developer substance, which latter solution has a temperature within the range of from 40 to 80 C. and a pH value from 3 to 10, after which the usual additional processing operations are carried out.

The present process can be applied to any desired material which contains silver halide and is advantageously free from developed substances. It is preferably used for the production of black-and-white pictures, though with the requisite further steps of processing it is also possible to obtain colour pictures. As mentioned above, the present process is specially suitable for X-ray films on which it is in general difiicult to obtain stable immediately visible pictures that satisfy insofar as contrast, gradation and fine grain are concerned.

According to the present invention the exposed photographic material is first treated in the manner described above with an aqueous solution which, owing to its content of an alkali metal hydroxide, has a pH value of greater than 10. Within the limits indicated above, the temperature may be freely chosen; as a rule it requires no further adjustment so that it is in most cases possible to work at room temperature since all that is needed in this connection is to impart a high pH value to the photographio material and to ensure that as yet no chemical reactions take place. The minimum treatment period of /2 second can be lengthened without adversely affecting the result, but as a rule there is no occasion to extend the treatment time beyond 2 seconds.

After the treatment of the material with the alkali metal hydroxide the material is treated with the developer substance for which purpose any desired developer may be used, for example, pyrocatechol, para-methylaminophenol sulphate, 1-phenyl-3-pyrazolidone or preferably hydroquinone. It is, of course, also possible to use a mixture of diiferent developers; for example, the developer substance may consist predominantly of hydroquinone to which a small proportion of l-pheuyl-3-pyrazolidone or para-methylaminophenol sulphate has been added. As is known strong contrasts are obtained with hydroquinone, while para-methylaminophenol sulphate and 1-phenyl-3-pyrazolidone give low contrasts. The total content of developer substance in the solution is from 25 to 60 g. litre and the pH value ranges from 3 to 10. The solution should have a temperature ranging from a minimum of 40 C. to a maximum of C. A temperature within the range from 60 to 70 C. has proved specially suitable. For the treatment with the developer solution a very short time of residence, ranging from 0.1 to 2 seconds, is adequate.

After having been treated with the developer the photographs can be finished off in the usual manner though it is as a rule very advantageous at this stage to treat the photographic material once more with an aqueous alkali metal hydroxide solution; this solution, which also has a pH value above 10, contains 20 to 250 g. of alkali metal hydroxide per litre and has a temperature from 10 to 80 C. This treatment, too, requires only a short time of contact of 0.1 second and as a rule no advantage is gained by extending it beyond 2 seconds.

For finishing oil the photograph the material is further processed immediately after the treatment with the developer or the second treatment with alkali metal hydroxide so that the development of image silver ceases; this can be done by a method 'known per se, for example by converting the unreduced silver halide into a silver compound that is inert towards the developer substance, or by converting it into a water-soluble sil'ver compound which is then washed out. As examples of such agents there may be mentioned thiourea, sodium thioglycollate, a thiocyanate or thiosulphate. From among the last-mentioned salts, for example, potassium or sodium thiocyanate or potassium thiosulphate and especially ammonium thiocyanate and sodium thiosulphate come into consideration. In general, it is specially advantageous to use a mixture of a thiocyanate with a thiosulphate. These stabilising or fixing solutions may have the usual concentrations and contain, for example 30 to 250 g. of thiocyanate and 10 to 200 g. of thiosulphate per litre of aqueous solution. It is advantageous to work at a temperature ranging from 20 to 80 C, and the time in which the photographic material is in contact with these solutions is, for example, /2 to 20 seconds. It may also be advantageous to work with separate solutions by treating the photographic material first with a thiocyanate solution and then with a thiosulphate solution. The pictures obtained by this method are specially stable.

The individual treatment baths may contain further substances conventionally used for the production of photographs. Thus, it is in general advantageous to incorporate a hardener for gelatine in the usual quantity, for example formaldehyde with at least one of the solutions mentioned above. 'It is of advantage if the first alkali metal hydroxide solutionand, when used, also the second-contains a hardener. An anti-fogging agent, for

example S-nitrobenzimidazole, is advantageously incorporated with the first alkali metal hydroxide solution. Furthermore, the individual solutions, such as first alkali metal hydroxide solution and/or the developer solution, may contain sodium sulphite or metabisulphite. An addition of potassium bromide to the developer solution may also be advantageous.

After having stabilised or fixed the photograph, the material is washed in water, for example for 2 to 20 secconsisting essentially of per liter 20-250 g. of sodium or potassium hydroxide, having a pH value greater than 10;

(2) for 0.1 to 2 seconds with anaqueous solution containing per liter 20-60 g. of developer substance selected from the group consisting of pyrocatechol, para-methylaminophenol sulphate, 1-phenyl-3-pyrazolidone and hydroquinone, this solution having a temperature from 40-80 C. and a pH value of 3-10, and

onds in water heated at 30 to 80 C., and finally dried 1 (3) once again for 0.1 to 2 seconds at 10-80 C. with in a current of air having a temperature of from 50 to an aqueous solution consisting essentially of '20-250 g. 90 C. of sodium or potassium hydroxide per liter,

The following table summarises the present process; any and thereafter carrying out the stabilizing or fixing steps feature essential to the invention is underlined. needed to finish off the photograph.

Tempcra- Content, Duration ture in Treatment step g./1itre in sees. 0. pH value Additives 1 Alkali metal hydroxide (NaOH). 20-250 %-2 10-80 10 Hardener (OHZO); anti- Iogging agent (ti-nitrobcnzimidazole) 2 Developer substance (hydroquinone) 20-60 0.1-2 40-80 3-10 Arggoxidan; (Na2SO 8.2 5 2.1 Alkali metal hydroxide 20-250 0.1-2 -80 10 Hardener (CHZO). 3 Finishing 0 3.11 Thiocyanate (NHtCNS) 30-250 20-80 3.12 Thiosulphate (Nazszoa) 10-200 %-2 20-80 3.13 '1lfiocgagagte and thiosulphate (NHlCNS plus %-20 20-80 3.2 Washing in water 2-20 30-80 3.3 Drying (current of hot air) 2-20 50-90 To enable the present process to be carried out suitably, that is to say to turn the exposed material into the finished 30 picture in a minimum of time, suitable apparatus is needed for the treatment with the requisite solutions. For example, the individual solutions may be sprayed on one after the other. It is especially advantageous to apply the solutions by roller apparatus.

The following example illustrates the present invention.

EXAMPLE An X-ray film, compirsing on both sides a silver bromide gelatin emulsion containing on each side 18 g. cf silver nitrate per square metre in the silver bromide, is successively terated with the following solutions:

(a)[1.] for 1 second at C. with 1000 parts of water 60 parts of NaOH 20 parts of aqueous formaldehyde, 37% strength (b) [2.] for 1 second at 70 C. with 1000 parts of water 50 parts of hydroquinone 3 parts of 1-phenyl-3-pyrazolidone 20 parts of sodium sulphite, anhydrous (c) [2.1] for 1 second at 50 C. with 1000 parts of water 60 parts of NaOH 20 parts of aqueous formaldehyde, 37% strength ((1) [3.1] for 3 seconds at 50 C. with 1000 parts of water 200 parts of ammonium thiocyanate 50 parts of sodium thiosulphate parts of aqueous formaldehyde, 37% strength.

The material is then treated for 3 seconds with water heated at 40 C. [3.2] and finally dried for 5 seconds in a current of air heated at 70 C. [3.3]. After this treatment, taking a total of 14 seconds, a stable, very contrasty and very black picture is obtained.

I claim:

1. A process for developing exposed X-ray photographic material containing silver bromide, which comprises: treating the material:

(1) for /2 to 2 seconds at a temperature within the range of from 10-80 C. with an aqueous solution 2. A process as claimed in claim 1, wherein, after having been treated according to claim 1, the X-ray photographic material is treated with a stabilizing or fixing solution, said solution being applied for at least 0.1 second.

3. A process as claimed in claim 1, wherein the material is finally washed in water for a short time and then dried at an elevated temperature.

4. A process as claimed in claim 1, wherein the time of residence in the first or second alkali metal hydroxide bath, in the developing bath and in the bath that finalises the development is at most 2 seconds, the time of washing in water is at most 4 seconds and the drying operation is at most 7 seconds.

5. A process as claimed in claim 1, wherein the aqueous solution (2) contains per litre 20 to 50 g. of developer substance.

6. A process as claimed in claim 2, wherein the fixing solution contains ammonium thiocyanate.

7. A process as claimed in claim 2, wherein the fixing solution contains sodium thiosulphate.

8. A process as claimed in claim 1, wherein at least one of the processing baths contains a hardener for gelatin.

References Cited UNITED STATES PATENTS 1,956,230 4/1934 Schmidt 9650 2,384,663 9/ 1945 Weissberger 9650 3,155,506 11/1964 Blake 96 50 3,168,400 2/1965 Blackmer 9666 3,232,761 2/1966 Allen 9666 3,266,898 8/1966 Levy 9650 3,284,199 11/1966 Matfet 9666 3,345,174 10/1967 Dotson 9661 3,404,981 10/1968 Harris 9650 3,545,971 12/1970 Barnes 9661 3,556,789 1/1971 Johnson 9650 PT NORMAN G. TORCHIN, Primary Examiner J. R. HIGHTOWER, Assistant Examiner US. Cl. XJR. 9663. 66