US3162534A - Photographic developer - Google Patents

Description

United States Patent Ollice 3,l52,53d Patented Dec. 22, 1954 3,162,534 PHGTGGRAPHHI DEVELQPER Augustin J. Powers, 31"., Old Broolcville, and George Schwarz, Glen Head, N.Y., assigncrs to Powers Chemco, Inc, Glen Cove, N..Y., a corporation of New York No Drawing. Filed June 26, 1962, Ser. No. 205,215 6 Claims. (U. %66) The invention relates to a novel and improved process for reenergizing formaldehyde bisulfite hydroquinone developers such as are used for the development of high contrast photographic film in the graphic arts, which developers are sometimes referred to briefly as litho developers.

Developers of this general kind are well known in the graphic arts and varieties of them are known in the trade as Chemeo Powerlith developer, Kodak D85, md others are described in some detail in the prior patents to Donovan and Wadman No. 2,313,523, Blake No. 2,533,990, Welliver and Krizka No. 2,902,367, l-lenn and Gofie No. 3,030,209, and Du Pont British Patent No. 643,411.

All of the prior litho developers have a relatively low capacity and begin to show substantial exhaustion after the development of a relatively small amount of lithofilm, and are discarded in commercial practice, due to the poor quality of negatives which are produced after only a selectively small quantity of film has been developed.

Additionally, in the development of lithotype emulsions in formaldehyde-bisulfite developers pepper spots often develop, as reported by Yule, in Journal of the Franklin Institute, March 1945, pages 221 to 230. It has now been found that such pepper spots often become prevalent when such developers are prepared from concentrated solutions which include an alcohol, such as ethyl alcohol, diethylene glycol or mcnomethyl ether of ethylene glycol; and the developing process and reenergizer of the present invention are not limited to such alcohol-containing developers, but extend the useful life of formaldehyde bisulfite developers in general.

Conventional replenishers for photographic developers, including high contrast developers, generally comprise a substantial quantity of a developing agent, such as hydroquinone; enough suliite, such as sodium sulfite, to prevent aerial oxidation of the developing agent; and an alkaline material, such as sodium hydroxide or carbonate, sufii cient to restore the partially exhausted developer bath to approximately its original activity. A relatively small amount of such a replenisher is added to the partially exhausted developer bath, after which the bath may be used for some further quantity of film.

According to the present invention, the surprising result has been found that an infectious developer bath (consisting essentially of a water solution of hydroquinone as the sole developing agent, carbonyl-alkali metal bisulfite, preferably formaldehyde-alkali metal bisulfite, alkali metal hydroxide, carbonate or borate and a restrainer such as potassium bromide) which soon begins to show signs of exhaustion after the development of only a relatively small amount of silver halide photographic film, such as lithe-film, may be substantially restored to its original activity and will produce film negatives of excellent quality, by reenergizing the developer bath, using only a small amount of solution consisting essentially of an alkali metal sulfite and a relatively small amount of an alkali metal hydroxide, which solution in relatively small quantities, is added to the partially exhausted developer bath.

Using the reenergizer of the present invention, the infectious de 'eloper bath, after it has been partially exhausted and would normally be discarded, may be reenergized and restored to substantially its original activity by mixing with it a small amount of the reenergizer, and the capacity of the developer bath may be increased to as much as 3, 4 or more times its normal capacity.

The present invention has for its object the provision of novel and improved method of reenergizing and greatly extending the useful life of an infectious developer bath. A further object is the provision of a novel and improved reenergizing solution for partially exhausted infectious developer baths. Another object is the provision of a novel and improved method of preventing undesired spots when using formaldehyde-bisulfite developers which include an alcohol in their composition. Still another object is the provision or" a novel and improved reenergizing solution by which an infectious developing bath may be maintained at good Working standards over a greatly extended film capacity, thereby resulting in greater economy and more uniform developed negatives.

it has now been found baths of litho developers may be reenergized after their normal useful life by adding to them small amounts of a concentrated aqueous solution of a sulfite ion and an alkali. Preferably, such a concentrated solution comprises sulfite ions, hydroxyl ions and one or more alkali metal ions, such as sodium and potassium. A mixture of different alkali metal ions are preferred so that the reenergizing solution may be more concentrated, although either sodium or potassium ions alone may be employed.

Thus, broadly, the reenergizing solution consists of sodium or potassium sulfite or bisulfite and sodium or potassium hydroxide or carbonate, preferably sodium, potassium, sulfite and hydroxide ions. This may be provided by a concentrated water solution of sodium sulfite and potassium hydroxide, such solution being as concentrated as can be reliably stored and shipped without crystalliza tion.

Typical of the formaldehydebisullite developers which may be used in the process of the present invention are those compounded within the ranges of the following general formula: i

Water to make 1.0 liter.

The quantity of the alkali used is chosen so that a pH range between 9.8 and 10.8 is obtained.

Reenergizers, according to the present invention, for such litho developers consist essentially of a concentrated water solution of sodium and potassium llOIlS and of hydroxyl ions and sulfite ions, and are preferably composed of sodium or potassium hydroxide or carbonate and/ or borate and sodium or potassium suliite or bisulfite, the alkali metal ions preferably being mixed. Such a solution may consist of:

Sodium or potassium sulfite grarns 100 to 250 Sodium or potassium hydroxide do 20 to Water to make 1 liter.

In the method of the present invention from 5 to 40 cc. of the reenergizing solution is added to each liter of partially exhausted litho developer bath, to restore the bath to substantially its original speed and activity. Thus, such additions comprise from 0.5 to 10 grams of sodium or potassium sulfite, combined with from 0.1 to 3.2 grams of sodium or potassium hydroxide, in a relatively concentrated aqueous solution, comprising sufiicient water to form from to 40 cc. of aqueous solution. This reenergizing ofthe bath may continue until the capacity of the bath has been extended even to as much as 3, 4 or more times the capacity of the bath with such novel reenerg-ization.

Typical of the infectious developers which are usually reenergized by the method of the present invention are the following; with respect to each of which the preferred reenergizer solution and its manner of use is specified:

Example 1 Solution A: Formaldehyde potassium bisulfite monohydrate grams 110 Hydroquinone do 135 7 Potassium hydroxide 45% water solution ml 2.8 Diethylene glycol ml 118 Ethylene diarnine tetracetic acid grams 0.26 Water to make 1000 ml.

Solution B:

Formaldehyde potassium bisulfite grams 63 Boric acid do 13.5 Potassium bromide do 1.57 Sodium hydroxide do 9.50

Water to make 1 liter.

Preferably, equal parts A and B are mixed and diluted with 4 parts of water to make six liters of working developer for development of litho film.

Replenisher (Solution C):

Sodium sulfite 116 grams". 440 grams.

Potassium hydroxide 45% water 256 m1 965 ml.

solution.

Water to make 1 liter 1 US. Gallon.

" As the working developer begins to show signs of exhaustion, 30 to 240 cc. preferably about 90 cc. of the replenisher per six liters of working developer are added and thoroughly mixed, whereby the working developer regains substantially its initial activity. Several such replenishing additions may be made before the bath is exhausted and ready to be discarded.

However, when developing certain types of film, such as Kodak Litho film Type III as presently sold, best results are obtained with it it about ml. per liter of replenisher is added before the first film is developed.

Example 2 Solution A:

Hydroquinone grams 40 Potassium formaldehyde bisulfite monohydrate I do 345 Ethyl alcohol cc 80 Water 'sufiicient to make 1 liter.

Solution B:

Potassium borate (anhydrous) "grams-.. 160 Potassium carbonate sesquihydrate do 204 Potassium bromide do 11.0

Water suflicient to make 1 liter.

For use one part of solution A and one part of solution B are mixed and diluted with 3 to 5 volumes of water based on the total volume of A and B solutions to. make 7 the working solution for development of litho film.

This developer bath may be reenergized several times v 4 by the addition to the bath of 5 to 40 cc. replenishing solution consisting of:

Potassium sulfite crystalline grarns 220 Sodium hydroxide do 66 In water solution liters..- l

or alternatively, a solution comprising:

Sodium sulfite anhydrous grams 144 Potassium hydroxide do 92 Water to make 1 liter.

or most preferably a Water solution of:

Sodium bisulfite grams Potassium hydroxide do 167 7 Water to make 1 liter.

Example 3 Solution A:

Potassium formaldehyde bisulfite monohydrate grams" 270 Hydroquinone do 100 Sodium bisulfite, anhydrous do 21 Ethyl alcohol 95% ml Water to make 1 liter.

Solution B:

' Potassium carbonate, sesquihydrate grams 340 Boric acid crystals do 55 Potassium bromide do 5 Water to make 1 liter.

For use one part of A is mixed with six parts of water and with one part of B to make a working developer.

The reenergizer may comprise:

Solution C:

Sodium sulfite, anhydrous grams 144 Potassium hydroxide d0 92 Water to make 1 liter.

From about 5 to 50 ml. of reenergizer per liter of developer are used to reenergize the developer and may be repeated several times.

Water to make 1 liter.

For use, one part of A and one part of B are added to two parts of water and mixed.

From about 10 to25 ml. of replenisher are used per liter of working developer.

Example 5 Another example of a litho developer and its reenergizer according to the present invention is as follows:

Solution A: 7

Sodium bisulfite grams 1.90 Formaldehyde sodium bisulfite do 37.00 Boric acid do 7.50 Hydroquinone do 22.50 Potassium bromide do 1.51

per liter of a I Solution B:

Sodium hydroxide grams Water to make 1000 ml.

For use equal parts of solutions A and B are mixed, and may be reenergized by additions of the energizer solution C.

Reenergizer Solution C:

Water solution comprising- Potassium sulfite anhydrous grams 150 Potassium carbonate "do-.." 150 Water to make 1 liter.

Example 6 Still another infectious developer and its reenergizing solution have the following formulation:

Water to make 1000 ml.

For use, equal parts of solutions A and B are mixed and used.

Solution C:

Potassium sulfite grams 100 Potassium carbonate do 120 Water to make 1000 ml.

Equal parts of solutions A and B are mixed for use.

When somewhat exhausted, the developer may be reenergized by adding 10 to 50 ml. of the Solution C per liter of developer, and may be repeated several times.

It should be understood that the renergizing solutions are preferably highly concentrated but may be diluted, so long as the working developer is not seriously diluted by their addition. Thus a solution such as Solution C of Example 1 may be diluted with 5 parts of water and from 150 to 1200 ml. used for each six liters of partially used Working developer. However, such dilution impairs the working developer, and for that reason, the reenergizer should be as concentrated as is practically possible.

The invention in its broader aspects is not limited to the specific steps, processes and compositions shown and described but departures may be made therefrom within the scope of the accompanying claims without departing from the principles of the invention and without sacrificing its chief advantages.

This application is a continuation-in-part of our prior co-pending application Serial No. 195,030, filed May 14, 1962.

What is claimed is:

1. A process for reenergizing and maintaining the activity of a hydroquinone containing carbonyl-bisulfite developer for lithographic film, the hydroquinone being the sole developing agent, which comprises adding to the developer, after some film has been developed therein, an aqueous solution consisting essentially of from 0.5 to 10 grams of an alkali metal sulfite and from 0.1 to 3.2 grams of an alkali metal hydroxide per liter of developer, the said aqueous solution being substantially free of hydroquinone and other organic developing agents.

2. A process for reenergizing and maintaining the activity of a hydroquinone containing carbonyl-bisulfite developer for lithographic film, the hydroquinone being the sole developing agent, which comprises periodically adding to the developer, per liter of developer, from about 5 to 50 cc. of an aqueous solution consisting essentially of from 100 to 250 grams per liter of an alkali metal sulfite and from 20 to grams per liter of an alkali metal hydroxide, the said aqueous solution being substantially free of hydroquinone and other organic developing agents.

3. A process for reenergizing and extending the activity of a used hydroquinone-containing formaldehyde-alkali metal-bisulfite developer for lithographic film, the hydroquinone being the sole developing agent, which comprises periodically adding to the developer, per liter of developer, from about 5 to 50 cc. of aqueous solution consisting essentially of from to 250 grams per liter of an alkali metal sulfite and from 20 to 80 grams per liter of an alkali metal hydroxide, the said aqueous solution being substantially free of hydroquinone and other organic developing agents.

4. A process as in claim 3 wherein the developer con ta-ins an alcohol.

5. A process as in claim 4 wherein the alcohol is selected from the group consisting of diethylene glycol and triethylene glycol.

6. A re-energizing solution for periodic addition to a carbonyl-alkali metal-bisulfite developer having hydroquinone as its sole developing agent consisting essentially of an aqueous solution of sulfite and hydroxyl ions and associated alkali metal ions selected from the group of salts consisting of sodium and potassium sulfites in a quantity of from 100 to 250 grams per liter and sodium and potassium hydroxide of from 20 to 80 grams per liter.

References Cited in the file of this patent UNITED STATES PATENTS 2,705,187 Teiziev March 29, 1955 3,030,209 Henn et a1 April 17, 1962 OTHER REFERENCES Axford et al.: Photographic Engineering, vol. 6, pages 50-4 (1955).

Hartsuch: Chemistry and Lithography, pages 166-7, Lithographic Technical Foundation, 131 E. 39th St., New York 16, N.Y. (1952).

Morehouse et al.: Journal Electrochemical Society, vol. 107, pages 361-5 (1960).

Derstuganov: Chemical Abstracts, vol. 51, page 4184 (1957).

Jayne et al.: Das Papier, vol. 6, pages 220-2. (1952).

Claims (1)

1. A PROCESS FOR REENERGIZING AND MAINTAINING THE ACTIVITY OF A HYDROQUINONE CONTAINING CARBONYL-BISULFITE DEVELOPER FOR LITHOGRAPHIC FILM, THE HYDROQUINONE BEING THE SOLE DEVELOPING AGENT, WHICH COMPRISES ADDING TO THE DEVELOPER, AFTER SOME FILM HAS BEEN DEVELOPED THEREIN, AN AQUEOUS SOLUTION CONSISTING ESSENTIALLY OF FROM 0.5 TO 10 GRAMS OF AN ALKALI METAL SULFITE AND FROM 0.1 TO 3.2 GRAMS OF AN ALKALI METAL HYDROXIDE PER LITER OF DEVELOPER, THE SAID AQUEOUS SOLUTION BEING SUBSTANTIALLY FREE OF HYDROQUINONE AND OTHER ORGANIC DEVELOPING AGENTS.