US2843483A - Photographic developer - Google Patents

Description

United States Pateflffi 2,843,483 PHOTUGRAPHIC DEVELOPER Donaid ill. Kridcl, Walter V. Wadman, and Joseph G. Stamptii, Rochester, N. Y., assigmors to Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey No Drawing. Application October 3, 1955 Serial No. 538,281

s Claims. (31. 96-66) This invention relates to photographic developers and particularly to photographic developer mixtures in dry form with which suitable solutions. for the development ofphotographic paper and film may be prepared. More particularly the present invention relates to improved developing compositions containing compounds which will markedly lessen the aerial oxidation in developers which are employed to produce the extreme contrast required in preparinghalf-tone or line negatives for use known materials which serve to improve the action of photographic solutions such as boric. acid and potassium bromide. Water soluble compounds such as citrates, sulphates and phosphates may likewise be added in solid condition to restrict the swelling of gelatin, or thelike. Fog restraining and inhibiting substances may bepresent. V

The components including the developing agent and the aldehyde bisulfite compound are mixed together in suitable proportions and then'may be packaged for distribution. The base component is generally not added to the powder mixture containing the developer since it might accelerate oxidation or deterioration of the developer. Also, the base in the presence of moisture could cause decomposition of the aldehyde bisulfite salts with loss of the aldehyde. The base component, therefore, can be included in a separate package or may be added to the developing solution at the time it is prepared.

This developing powder mixture forms the developing solution when added to water in the presence of a base.

The base reacts with the aldehyde-sulfite compound causing it to decompose into aldehyde and sulfite. Strong inorganic bases such as sodium hydroxide, sodium carbonate, etc, increase the rates of aldehyde formation and are preferred. They are also desirable to employ since they provide an increased contrast. Phenol type developers such as hydroquinone, ortho catechol, and chlorhydroquinone may be employed in the above described developer compositions.

, It has been found, however, that the developers described in the above-mentioned patent are quite susceptibleto aerial oxidation. When the developer solution is exposed to the air in developing trays it rapidly discolors and loses activity. An increasing developing time is, therefore, required to maintain the desired image density as the aerial oxidation proceeds. This adds an additional variable to a process which is already critical in respect to other variables.

y The present invention therefore is an improvement over the invention described, of course, more completely in Patent 2,313,523 than in certain of the foregoing parar Eatented, July 15, 1958 graphs. We have discovered that if in addition to the bisulfite compounds of formaldehyde mentioned in the patent, small concentrations of sodium and/ or potassium bisulfite compounds of other carbonyl compounds are present, the aeration life of these developers is greatly improved. The. presence of the sodium and/ or potassium bifulfite compounds of acetone, acetaldehyde, aldol, isobutyraldehyde, methyl ethyl ketone, glyoxal, methoxy acetaldehyde is particularly eifective in increasing this aeration life.

For example, sodium formaldehyde bisulfite has a low dissociation constant in the type of photographic developer in which it is ordinarily used. The dissociation constant is a measure of the degree of separation ofa compound into its components and in this case is expressed as:

whereK is the dissociation constant, (CS) the concen tration of dissolved but associated carbonyl bisulfite compound, and (H+), (C), (S) the concentrations of hydrogen ion, carbonyl compound, and sulfite respeclatter, however, if used alone have a detrimental eifect on the sensitometric properties of the complete developer. However, we-have found in accordance with the present invention that when the aforementioned carbonyl bisulfite compounds are employed with sodium formaldehyde bisulfite they will give excellent protection against oxidatlon without any appreciable effect on the sensitometric properties. 2

Concentrations of the order of 5 to 15 grams per liter of one or more of these additional bisulfite compounds produce an appreciable improvement in stability toward aerial oxidation without appreciably changing the speed, contrast, or dot quality produced by the initial solutions.

To illustrate the improvement of the present invention over that described in Patent 2,313,523, developers were prepared in which formaldehyde sodium bisulfite alone was used and also in which a portion of the formaldehyde bisulfite was replaced by another carbonyl bisulfite compound, in accordance with the present invention.

They were compared in a test which is often used on this type of developer, called a tray life test. The respective developer solutions are poured into individual 12 x 14 inch development trays to a depth of approximately /2 inch and allowed to stand 8 hours in a conditioned room at 72 F. Test strips, which have been exposed identically, are developed under identical conditions at the start and after 4 an'd8 hours standing. The densities of the images on the strips are read on a densitometer from which can be computed the developer speed at successive times and from these the speed loss of the developer on standing in the open is obtained.

The general'formula for the developers was as follows:

Grams Total carbonyl bisulfite compounds 36.0 Composed of:

Sodium or potassium formaldehyde bisulfite 21.0-36.0 Other carbonyl bisulfite 5.0-l5.0 Hydroquinone 22.5 Boric acid 4.0 Sodium carbonate, monohydrate 55.0

Potassium bromide 1.6

formaldehyde bisulfite.

3 The chemicals are dissolved in the order given above in suflicient water to make 1 liter total volume to form the developer solution.

Example 1 A developer was prepared containing 9.0 grams of sodium acetone bisulfite and 27.0 grams of sodium formaldehyde bisulfite instead of 36.0 grams of the sodium or potassium formaldehyde bisulfite in the above formula.

It showed a speed gain of 12% and 24% after 4 and 8 hours standing respectively compared with a speed loss of 50% and 83% for the formaldehyde bisulfite alone.

Example 2 7 A developer was'made which contained 9.0 grams of -sodium' isobutyraldehyde bisulfite and 27.0 grams of sodium formaldehyde bisulfite instead of the same total of the sodium or potassium formaldehyde bisulfite. It

: produced a speed gain of 3% after both 4 and 8 hours standing as compared with a loss of 50% and 83% for the formaldehyde bisulfite.

Example 3 Another developer was prepared with 15.0 grams of :sodium acetaldehyde bisulfite and 21.0 grams of sodium formaldehyde bisulfite in place of all sodium or potassium The speed loss Was 34% and 59% after 4 and 8 hours respectively in comparison to 50% and 83% for straight formaldehyde bisulfitea Example 4 In another developer, 15.0 grams of sodium methyl ethyl ketone bisulfite and 21.0 grams of sodium formaldehyde bisulfite was employed instead of all sodium or potassium formaldehyde bisulfite. There was no speed loss but instead a gain in speed of 13.0% and 11.4%

after 4 and 8 hours standing.

Example 5 In another developer, 12 grams of sodium glyoxal bisulfite was used to replace the same weight of sodium formaldehyde bisulfite. Its speed loss after 4 and 8 hours was 32 and 60% compared with 50 and 83% for formaldehyde bisulfite alone.

Example 6 In another case, 6 grams of potassium acetone bisulfite replaced that weight of the sodium or potassium formaldehyde bisulfite. The developer showed a speed gain of 17.7% after 4 hours and a loss of 6% after 8 hours instead of losses of 50% and 83% respectively with straight formaldehyde bisulfite.

Example 8 In another instance, 5 grams of sodium acetone bisulfite were substituted for that weight of sodium formaldehyde bisulfite. This time the resultant developer gained 25% in speed after 4 hours and lost 16.7% after 8 hours instead of the 50% and 83% losses with formaldehyde bisulfite.

Our invention therefore has the particular advantage r 4 of preventing aerial oxidation of developer solutions containing sodium or potassium formaldehyde bisulfite and prevents loss of development speed.

We claim: 1. A photographic developer composition containing an organic silver halide developer, an alkali, a buffer component, a carbonyl bisulfite component consisting of at least one alkali metal carbonyl bisulfite selected from thegroup consisting of sodium and potassium formaldehyde bisulfite and at least one alkali metal carbonyl bisulfite selected from the group consisting of sodium and potassium carbonyl bisulfite compounds having two to six carbon atoms in the molecule and having a higher dissociation constant than sodium formaldehyde bisulfite.

2. A photographic developer composition containing an organic silver halide developer, an alkali, a buffer component, an antifoggant, a carbonyl bisulfite component consisting of at least one alkali metal carbonyl bisulfite selected from the group consisting of sodium and potassium formaldehyde bisulfite and at least one alkali metal carbonyl bisulfite selected from the group consisting of sodium and potassium carbonyl bisulfite compounds having two to six carbon atoms in the molecule and having a higher dissociation constant than sodium formaldehyde bisulfite.

3. A photographic developer composition containing hydroquinone, sodium carbonate, boric acid, potassium bromide, a carbonyl bisulfite component selected from the group consisting of sodium and potassium formaldehyde bisulfite and at least one alkali metal carbonyl bisulfite selected from the group consisting of sodium and potassium carbonyl bisulfite compounds having two to six carbon atoms in the molecule and having a higher dissociation constant than sodium formaldehyde bisulfite.

4. A photographic developer composition containing an organic silver halide developer, an alkali, a carbonyl bisulfite component consisting of sodium formaldehyde bisulfite and sodium acetonebisulfite, a buffer component, and an antifoggant.

5. A photographic developer composition containing an organic silver halide developer, an alkali, a carbonyl :bisulfite component consisting of sodium formaldehyde bisulfite and sodium isobutyraldehyde bisulfite, a buffer component, and an antifoggant.

6. A photographic developer composition containing an organic silver halide developer, an alkali, a carbonyl bisulfite component consisting of sodium formaldehyde bisulfite and sodium acetaldehyde bisulfite, a buffer component, and an antifoggant.

7. A photographic developer composition containing an organic silver halide developer, an alkali, a carbonyl bisulfite component consisting of sodium formaldehyde bisulfite and sodium methyl ethyl ketone bisulfite, a buffer component and an antifoggant.

8. A photographic developer composition containing an organic silver halide developer, an alkali, a carbonyl bisulfite component consisting of sodium formaldehyde bisulfite and sodium glyoxal bisulfite, a buffer component and an antifoggant.

References Cited in the file of this patent UNITED STATES PATENTS 707,403 Eichengrun Aug. 19, 1902 2,313,523 Donovan et al. Mar. 9, 1943 I 2,458,376 Henn Jan. 4, 1949

Claims (1)

1. A PHOTOGRAPHIC DEVELOPER COMPOSITION CONTAINING AN ORGANIC SILVER HALIDE DEVELOPER, AN ALKALI, A BUFFER COMPONENT, A CARBONYL BISULFITE COMPONENT CONSISTING OF AT LEAST ONE ALKALI METAL CARBONYL BISULFITE SELECTED FROM THE GROUP CONSISTING OF SODIUM AND POTASSIUM FORMALDEHYDE BISULFITE AND AT LEAST ONE ALKALI METAL CARBONYL BISULFITE SELECTED FROM THE GROUP CONSISTING OF SODIUM AND POTASSIUM CARBONYL BISULFITE COMPOUNDS HAVING TWO TO SIX CARBON ATOMS IN THE MOLECULE AND HAVING A HIGHER DISSOCIATION CONSTANT THAN SODIUM FORMALDEHYDE BISULFITE.