US3516829A - Photographic activator solution - Google Patents

Photographic activator solution Download PDF

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Publication number
US3516829A
US3516829A US534648A US3516829DA US3516829A US 3516829 A US3516829 A US 3516829A US 534648 A US534648 A US 534648A US 3516829D A US3516829D A US 3516829DA US 3516829 A US3516829 A US 3516829A
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US
United States
Prior art keywords
activator
emulsion
formaldehyde
image
sodium
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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US534648A
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English (en)
Inventor
Robert George Clarke
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Eastman Kodak Co
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Eastman Kodak Co
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Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
    • G03C5/00—Photographic processes or agents therefor; Regeneration of such processing agents
    • G03C5/26—Processes using silver-salt-containing photosensitive materials or agents therefor
    • G03C5/262—Processes using silver-salt-containing photosensitive materials or agents therefor using materials covered by groups G03C1/42 and G03C1/43
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
    • G03C5/00—Photographic processes or agents therefor; Regeneration of such processing agents
    • G03C5/26—Processes using silver-salt-containing photosensitive materials or agents therefor
    • G03C5/29—Development processes or agents therefor
    • G03C5/315—Tanning development
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/004—Photosensitive materials
    • G03F7/06—Silver salts

Definitions

  • an image in soft adhesive organic colloid is formed photographically and a discrete stratum of the image is transferred to a receiving sheet to provide a reproduction of the subject.
  • This process is described in Yutzy et al., US. Pats 2,596,756, issued May 3, 1952, and 2,716,059, issued Aug. 26, 1955, and embodies the exposure to a subject of a substantially unhardened gelatino-silver halide emulsion layer, which may contain a gelatin tanning silver halide developing agent as well as a nontanning silver halide developing agent.
  • tanning development of the most exposed regions of the emulsion corresponding to the highlights of the subject proceeds, although some development of the less exposed regions also takes place to provide visual density for the transferred image as explained in U.S. Pat. 2,716,059 above.
  • the developed emulsion is pressed into contact with an absorbent receiving sheet to cause the less exposed regions and less developed regions, of the emulsion to adhere to the receiving sheet.
  • a stratum of the less exposed regions of the emulsion remains on the sheet and appears as a positive silver image of the original subject.
  • the exposed unhardened emulsion is immersed in an alkaline activator solution which causes development of the most exposed regions and tanning in these areas.
  • the mechanism of the colloid transfer depends upon the unhardened areas of the emulsion transferring to the receiver sheet when the emulsion is pressed in contact therewith.
  • the transferred image areas are of unhardened gelatin and relatively soft in nature so that in some instances too much unhardened gelatin is transferred to the support for satisfactory use. With some activators, image bleeding also occurs.
  • the alkaline activator solutions which are commonly used have a temperature latitude of 8183 F. to obtain satisfactory lithographic plates or copies. Athigher temperatures, image bleeding may increase. At temperatures, image bleeding may increase. This means that a controlled environment is desirable in order to obtain the optimum results.
  • the activator should have greater temperature latitude, preferably operating ranges as high as 93-96 F.
  • One subject of this invention is to provide an alkaline activator solution which will provide satisfactory lithographic plates from colloid transfer emulsions. Another object is to provide an activator for colloid transfer systems having an operating working temperature up to about 96 F. and as low as 65 F. A further object is to provide an improved lithographic plate from a colloid transfer process having uniform photographic characteristics. An additional object is to provide a method of processing colloid transfer materials which results in an image having a good inking rate and good oifset quality.
  • a still further object is to provide a method of regulating the amount of unhardened gelatin transferred in the colloid transfer process to improve resistance to copy bleeding and transfer of background.
  • the above objects are obtained by employing a conventional activator solution to which has been added an amphoteric metal salt. There may also be added formaldehyde or a formaldehyde donor. When this activator solution is used for development of a colloid transfer emulsion in the presence of a tanning silver halide developer, the addition of a hydrolysis product of the formaldehyde donor may also be desirable.
  • the aluminum is used as the amphoteric metal.
  • the range of concentration of alumniate ion with respect to formaldehyde donor e. g., 3-fi-hydroxyethyl oxazolidene
  • formaldehyde donor e. g., 3-fi-hydroxyethyl oxazolidene
  • the range of salt supplying the aluminate ion is from 50 mg. (0.005%) per liter to 3 g./l. (0.3%); when using 5 gm. (0.5%) per liter of formaldehyde donor, (e.g., oxazolidene) and 10 g./l. (1%) of 2,2-iminodiethanol, the range may be from a low of 25 mg. (0.0025%) per liter to a high of 1 gm. (0.1%) per liter.
  • Aluminum metal can be dissolved in a strong base such as sodium or potassium hydroxide.
  • Water soluble salts of aluminum such as aluminum sulfate, aluminum nitrate, and aluminum chloride can be used as long as the final product in which they are used is maintained at a pH above the point where the precipitation of insoluble aluminum hydroxide occurs.
  • Aluminum hydroxide, alumina (hydrated or dehydrated aluminum oxide), alum or other double salts of aluminum such as sodium aluminum sulfate can all be used.
  • aluminate ion has been used herein to illustrate my invention but it will be understood that the other amphoteric metals can be added to activator solutions ICC amount of -40 grams per liter.
  • Sodium salicylate may be incorporated in an amount of 012.5 grams per liter.
  • a sequestering agent such as a sodium salt of ethylenediamine tetraacetic acid in an amount of about 0-5 grams per liter. This is especially helpful where hard waters are used.
  • a particularly useful amount of the amphoteric metal salt may be 50 mg. to 3 g./l. of the activator solution.
  • Salts of various amphoteric metals may be used including, for example, those supplying ions of aluminate, zincate, plumbate, chromate, molybdate, stannate, etc.
  • the activator solution must be alkaline and is particularly useful at a pH of or above.
  • Activators containing formaldehyde in trace quantities of about 30-250 mg./liter of the free formaldehyde are also useful, the use of a formaldehyde donor rather than formaldehyde itself provides an activator solution in which the amount of free formaldehyde can be maintained at the desired level.
  • gelatin softeners such as, for example, potassium isophthalate, potassium para toluene sulfonate, sodium benzoate, potassium nitrate, cinnamic acid, sodium salicylate, etc.
  • Inorganic bases such as the carbonates
  • phosphates and the like in an amount of 0-40% by weight. Additional variations can be made by substituting alkali salts such as sodium or potassium carbonate, trisodium phosphate, sodium or potassium hydroxide, etc.
  • the activators can be made up as concentrates.
  • a useful two-package concentrate comprises one package containing the salt of the amphoteric metal in an amount of 0.01% to 1.5% by weight, hydrolysis product of the formaldehyde donor, sodium bicarbonate, sodium salicylate, ethylenediamine tetraacetic acid and (if desired) a small amount of water. This can be mixed with the second packages contents comprising 0.40% to 0.20% by weight of the formaldehyde donor.
  • all of the components may be included in the same package or same mixture and sold as a concentrate.
  • the salt of the amphoteric metal would usefully constitute 0.01% to 1.5%.
  • formaldehyde donor it may be present in an amount of about 0.4% to 2.0%.
  • Other components may also be used, including those which are conveniently used in activator solutions.
  • an alkali metal hydroxide such as sodium hydroxide could be present in an amount of about 60% and acids could be added to provide other desirable ions.
  • Typical acids include phosphoric acid and cinnamic acid. It is also useful to incorporate a sequestering agent, such as ethylenediamine tetraacetic acid.
  • the packaging of the concentrate will depend somewhat on the amount of water present.
  • the concentrate could be in paste or powder form whereas for other purposes, it might be in a concentrated solution.
  • it could be prepared with all the components in one package or one or more of the components could be packaged separately for ease in shipment, stability, or the like.
  • activator solutions containing a salt of an amphoteric metal are useful in providing improved lithographic printing plates
  • the activator can also be used for making copies according to the colloid transfer process in the customary manner.
  • These activators have a relatively long tank life of 4 to 6 months and can be replenished merely by adding more of the same activator.
  • iminodiethanol added to an activator containing 3-B-hydroxyethyl oxazolidine serves to increase the tolerance of the activator for this formaldehyde donor.
  • An activator containing 20 g./ 1. of iminodiethanol will tolerate 10 g./l. of axazolidine while the same activator without iminodiethanol will fail to work at 2 g./l. level of 3-,B-hydroxyethyl axozolidine.
  • the formaldehyde donor may be in corporated in the colloid process silver halide emulsion as well as the donor hydrolysis product.
  • a very small amount of formaldehyde donor and donor hydrolysis product incorporated in the substantially unhardened silver halide emulsion unexpectedly improves the number of copies obtained in certain instances employing document copy methods.
  • EXAMPLE 1 An activator for the colloid transfer process was prepared by mixing the following components:
  • the activator as prepared above was used in a colloid transfer process of the type described in Yutzy et al., U.S. Pat. 2,596,756.
  • a good quality print was obtained by transfer of the unexposed areas.
  • the temperature of the activator was 83 F.
  • the transferred 5 image was then immersed in an image conditioner to improve the wetting properties of the paper base and the inking properties of the image.
  • the image conditioner had the following composition:
  • the printing plate was a good photographic reproduction and when used directly in a lithographic printing press was found to be satisfactory for offset use.
  • the image readily accepted greasy printing ink and had good reproducing characteristics. A thousand copies were prepared, indicating good press life.
  • Example 2 was prepared with suflicient water added to make 1 liter of solution and used as in Example 1. Good results were obtained. It was also used to make copies by the colloid transfer process with good results.
  • a typical activator when the concentrate is mixed with water has the following composition:
  • EXAMPLE 5 An activator having wide temperature latitude was prepared as follows:
  • tanning developers and/ or nontanning developers may also be incorporated in the developer or activator solution as well as in the emulsion providing the unhardened silver halide emulsion is developed in the presence of at least one tanning silver halide developer.
  • an unhardened silver halide emulsion is intended one that is not harder than a gelatin layer containing 0.7 gram of formaldehyde per pound of gelatin freshly coated.
  • the silver halide sensitized sheet may be exposed by projection or contact printing methods under a two-tone subject such as a line or half-tone transparency or printed matter. If desired, reflex exposure methods may be used for making the exposure.
  • the support, to which the unhardened stratum is transferred is preferably a paper stock which has thereon a gelatin overcoat. However, other surfaces may be used to receive the transferred image, including metal plates, polymeric plates and the like. Additional useful printing plates are described in US Pats. 2,763,553 and 2,794,388.
  • the sensitive element When the development is complete as determined by trial with the particular emulsion in conditions of operations and use, the sensitive element is pressed into contact with the receiving material such as paper "by means of a squeegee blade or rollers. Immediately thereafter, the sensitive element and receiving support are separated, leaving a stratum of the less exposed and thus less hardened regions of the emulsions adhering to the receiving sheet.
  • the receiving material such as paper "by means of a squeegee blade or rollers.
  • the developing agent or agents are present in the emulsion.
  • the developing agent or agents may be present in the alkaline activator solution or both in the emulsion.
  • a very useful combination of developing agents is 4-phenylcatechol with 4-methoxy-alpha-naphthol. Since the latter is self-coupling, it forms a colored compound 7 during developing which contributes density to the print.
  • Other useful tanning and nontanning silver halide developing agents are disclosed in the above patents.
  • a useful image conditioner which can be used for treating the transferred image on the printing plate comprises a mixture of a condensate of .2 to .6 mole of Z-furaldehyde with 1 mole of resorcinol, tannic acid, 1,3-diethyl- 2-thiourea, glycerol, ethyl alcohol, glacial acetic acid, and water. At least 10 percent of the concentrate is used.
  • Other useful proportionate ranges are as follows:
  • the image conditioner may be applied by any convenient method such as swabbing the image, immersing in a conditioner bath or the like.
  • the 2-furaldehyde and resorcinol condensate can be prepared by dissolving the resorcinol in warm water, cooling to room temperature and adding the 2-furaldehyde. A small amount of sodium hydroxide is added and the reaction permitted to continue until the condensate is formed. The remaining components of the image conditioner can then be added to the reaction solution without separating the condensate.
  • An aqueous alkaline activator solution for use in developing a substantially unhardened gelatino-silver halide emulsion in the presence of a tanning developer, said solution containing:
  • (-b) ions selected from the class consisting of aluminate, zincate, plumbate, chromate, molybdate, and stannate ions, at a concentration equivalent to that which would be provided by about 3 g. to about 50 mg. of sodium aluminate per liter of solution;
  • gelatin softener comprising moieties selected from the group consisting of isophthalate, p-toluenesulfonate, 'benzoate, cinnamate, and salicylate;

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Photosensitive Polymer And Photoresist Processing (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
US534648A 1966-03-16 1966-03-16 Photographic activator solution Expired - Lifetime US3516829A (en)

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US53464866A 1966-03-16 1966-03-16

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US (1) US3516829A (cs)
BE (1) BE695547A (cs)
DE (1) DE1547795B1 (cs)
FR (1) FR1516507A (cs)
GB (1) GB1170659A (cs)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2199904A (en) * 1938-03-17 1940-05-07 Rca Corp Photographic developer
US3189449A (en) * 1962-10-01 1965-06-15 Eastman Kodak Co Colloid stratum transfer process

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2199904A (en) * 1938-03-17 1940-05-07 Rca Corp Photographic developer
US3189449A (en) * 1962-10-01 1965-06-15 Eastman Kodak Co Colloid stratum transfer process

Also Published As

Publication number Publication date
DE1547795B1 (de) 1970-01-15
FR1516507A (fr) 1968-03-08
BE695547A (cs) 1967-08-14
GB1170659A (en) 1969-11-12

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