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
  • G03C5/40—Chemically transforming developed images
  • G03C5/46—Toning

Definitions

• Another object of the present invention is to provide an improved process for toning the redcoior component image for multi-color photog- 25 raphy.
• our process consists in 30 transforming the silver image on a photographic print into a latent or patent metallic salt image, while converting the metallic silver present into a compound readily removable in a suitable solvent, such as hypo, and transforming 35 the metallic salt image into an image of a red color having approximately the same form and gradation as the original print, the silver compound present being removed from the print desired color by treatment with a coiorprecipi-' 50 tant.
• the finished print is to be tonedmagenta, which is the primary red of color photography.
• the print is first preferably treated to 5 transform the silver image into an image of nickel ferrocyanide which is subsequently reacted upon with a suitable color precipitant to deposit a pigment of a magenta colo
• the general procedure followed in the practice of the present invention involves the initial treatment of a silver photographic print in a bath containing nickel ionsand-also ferricyanic acid ions, the bath containing a suitable reagent to prevent the precipitation of nickel ferricyanide.
• the silver print When the silver print is immersed m in a bath of the character referred to, it appears that the' metallic silver present on the print eiiects the precipitation of nickel ferrocyanide, the silver functioning as a reducing agent. 1 Since the nickel ferrocyanide will be deposited only where silver particles occur on the print and to a degree corresponding to the con centration of the silver particles in any given portion of the print, the nickel ferrocyanide particles will have substantially the same distribution as the original silver particles. In serving as a reducing agent to efiect the precipitation of nickel ferrocyanide, the metallic silver is converted into silver oxide or hydroxide, which, by virtue of the ferricyanic acid ions present, is converted into silver ferricyanide.
• the silver ferricyanide may be removed from the print, as in a hypo solution, either during the first stage of treatment of the print or after the second stage of the toning operation. In either case, the print which has nickel ferrocyanide deposited thereon is treated with a color precipitant to convert the nickel ferrocyanide into a pigment of a red color.
• the treating bath employed in the first stage of the process comprises an aqueous medium to which has been 'added a soluble ferricyanide of a metal which will not form an insoluble compound with any other ion present in the treating bath; a soluble salt of nickel; a reagent ca- 40 pable of preventing the precipitation in the bath of a ferricyanide of nickel; anacid; and, preferably, an aqueous solution of formaldehyde, such as commercial formalin.
• the treating bath should include a solvent for the silver compound 'all of the constituent reagents at one time, it is advisable to withhold the addition of the solu- 55 ble ferrlcyanide until Just prior to the use of the treating bath.
• any soluble ferricyanide of a metal which does not form an insoluble compound with any other ion present in the treating bath such as potassium, sodium or ammonia ferricyanide. Our preference is for potassium ferricyanide.
• soluble salt of nickel may be employed in the preparation of the treating bath, such as the nitrate, sulfate, acetate, chloride, bromide, iodide or the like. Where reference is made to a "soluble salt it is meant that the salt will provide a solution of more than one per cent. concentration at 20 C.
• citric acid for the purpose of acidifying the treating bath we prefer to employ citric acid although other acids will serve, including both organic and in-' organic acids, such as tartaric, acetic, oxalic, hydrochloric, nitric, or the like.
• a reagent which will prevent the precipitation of a ferricyanide of nickel, while permitting the precipitation of the ferrocyanide of nickel.
• any freely soluble salt which in aqueous solution, in concentrations above approximately ten percent. by weight, is a solvent for nickel ferricyanlde but which will not dissolve very appreciable amounts 'of the corresponding ferrocyanide.
• a solution of a salt which is a selective solvent for the ferricyanide when both the ferrocyanide and ferricyanide are present.
• the salt employed serves as an inhibitor or retardant of reaction between the nickel salt present and the soluble ferricyanide present to form an insoluble ferricyanide precipitate.
• such inhibitor or retardant of the precipitation, of an insoluble ferricyanide. is potas-.
• sium citrate but in place thereof we may employ'any.
• the salt may be any that will provide a solution which is a selective solvent for nickel ferricy'anide when the same is present with a-corresponding ferrocyanlde.
• dou-' ble salts may be employed, such as potassium sodium tartrate.
• the silver print to be toned is immersed therein untiithe. silver image is thoroughly bleached; The treated print is then re-- moved from the bath and thoroughly washed in running water until all water-soluble compounds have been removed.
• ait is desirable to remo the silver compound present on the treated prior to the second stage of treatment with a color precipitant. This may be accomplished by including hypo in the original treating bath or by treating the print with a hypo. solution after the first stage of treatment. Wherehypo is included in the treating bath the amount of such reagent present must be controlled in order that the particles of color intermediate will be deposited on the printin substantially the same distribution as theorlginal silver particles before the silver is removed in solution.
• the print After the print from the first stage of the process has been washed, and the silver content removed if.desired, the print is 'then treated with, a color precipitant to convert the particles of color intermediate into a pigmentof red color,
• the color precipitant employed will depend upon the compound deposited as a color intermediate and the final color desired in the toned print.
• Example I According to this example the half-tone image of a silver photographic print is converted into an image. of a magenta color which is the subtractive red or minus green of subtractive color -printing.
• This example covers our preferred other inhibitor of reaction between a soluble nickel salt and an alkali-metal ferricyanide with the formation of a nickel ferricyanide precipitate; 30 grams of citric acid; preferably, 100 cc. formalin (40 per cent. aqueous'formaldehyde solution); and sufiicient water to make up one liter of solution.
• This solution may be prepared as far in advance of use as desired since it is capable of, being stored over long periods.
• the formaldehyde content may be reduced or omitted without entirely de-,- stroying the usefulness of the solution.
• it ispreferred to include the formaldehyde since it not only acts as a preservative for the solution but also as a hardening agent for the gelatin on the prints treated in .the solution.
• the formaldehyde also prevents the swelling of the gelatin emulsion on the films treated when the treating bath is used in a relatively warm surrounding atmosphere. Inasmuch as the formaldehyde does not serve its desired purpose where the treating bath is either alkaline or strongly acid, we prefer to maintain the pH value ofthe treating bath either at approximately 7 or only slightly on the acid side.
• the first-stage treating bath is prepared by mixing 100 cc. of the above solution with 20 cc. of a 15 .per cent. solution of potassium ferricyanide' or other soluble ferricyanide of a metal which will not form an insoluble compound with any of the other ions present in the treating hath.
• the photographic print to be toned After the photographic print to be toned has been developed and printed in conventional manner it is thoroughly washedto remove the last trace of hypo and is then immersed in the above described treating bath for about 15 to 20 minutes, or-until the silver image on the print is thoroughly bleached. The print is then washed in running water or several changes of water to remove substantially completely all water soluble compounds present. The print is then immersed in a color precipitating bath or red developer-which is preferably prepared by mixing and heating together at about 50 C. for 30 minutes 30 grams of dimethylglyoxime, 250 cc. of
• This alternative color precipitating bath is prepared by heating the mixture of the two amines and the dioxime at about 100 C. for approximately minutes to effect the solution of the dioxime in the mixture of amines and to eifect what appears to be a reactionof the ingredients inasmuch as the solution which is'initially colorless turns to a pale reddish brown color. heating of the ingredients as described, there is then added the amount of water necessary to make up a liter of solution.
• the print is immersed in the red developer solution for about 10 minutes, or until the red color completely develops. After the color has developed the print is removed from the bathand immersed in either a 5 per cent. solu- ,tion' of hypo or about a 10 percent. aqueous red developer containing this compound as the print a pigment consisting of nickei-dimethylglyoxime.
• any dioxime may be employed in the red developer such as alpha-benzyldioxime, methylp'ropylglyoxime, or alpha-furyl dioxime.
• the nickel compounds of these other dioximes are not true magenta in color and, therefore, where a truemagenta is desired it is preferred to employ dimethylglyoxime.
• the solvent for the dioxime employed in preparing the red developer may consist exclusivelyof alcohol, acetone or the like
• a solvent comprising a mixture of amines as described above since by the use of such solvents a more brilliant color is obtained and, where the print has been prepared on strip film.
• the mixed amine solvent does not shrivel the collodion backing as does a solvent such as alcohol alone.
• amine mixture employed as the preferred solvent in the red developer described above
• monoethanolamine may be used alone as a solvent for the dioxime employed.
• Triethanolamine may also be used alone but the results obtainedtherewith are not completely satisfactory.
• tertiary amines such as tertiary butyl amine.
• Example 2 According to this example there is obtained a final toned print of substantially the same color as produced by the preferred practice of the process described under Example 1. However, the print is somewhat less transparent and brilliant in color although the appearance of the print is substantially superior to red toned prints prepared by any of the prior art processes of which we are aware.
• the silver compound formed during the treatment will be removed from the print in solution, leaving correspondingly distributed particles of nickel-ferrocyanide in place thereof.
• the print After the print has been treated in the firststage treating bath for the required period of 'time, it is removed from the bath and thoroughly washed in running water until all water soluble compounds have been removed. Generally, the print should be washed for from 15 to 20 minutes in runnlngwater.
• the washed print is then contacted with a dioxime and ammonia.
• the print is immersed in a solution containing a dioxime and a water-soluble or water-miscible solvent there- I for.
• the print After the printhas been immersed in this solution for a sufficient period of time to soak up a substantial amount of the dioxime solution, it is then removed therefrom and immersed in a rela-
• the print may be immersed in a solution of one gram of 'dimethylglyoxime dissolved in cc. of a methyl alcohol or other water-soluble or watermiscible solvent such as another alcohol, acetone or the like. :The print is allowed to remain in such'solution for about two or three minutes. or
• aqueous solution of ammonia such as a 5% ammonia solution.
• ammonia solution may be prepared by mixing 1 part of commercial (28%) ammonia with 5 parts of water. The print is permitted to remain in the ammonia solution for about 5 to 10 minutes, after which the print is removed from the ammonia bath and washed thoroughly in running water for from approximately 10 to 20 minutes.
• vW'hile in the present modification of the secondstage of the process it is desired to introduce the print first into the alcoholic solution of 'dimethyl glyoxime and thereafter into anammonia solution, it is'possi'ble to produce satisfactory results by carrying out the two operations in a single stage by adding ammonia to the alcoholic.solu-- Dimethyl glyoxime gram 1 Commercial methyl alcohol; cc 28% ammonia solution cc 10 In case the print has been made on a strip film instead of on photographic paper, approximately 40 cc. of water should be added to the above solution to prevent the curling of the film of Celluloid in the strip film.
• we preferably remove the silver content of a photographic print during .the toning operation or after the production of the toned print with an alkali-metal thiosulfate, such as a conventional hypo solution.
• an alkali-metal thiosulfate such as a conventional hypo solution.
• an alkali-metal thiosulfate can advantageously be eliminated in the toning procedure by substivtuting therefor a small amount of potassium thiocyanate or other alkali-metal thiocyanate, including ammonium thiocyanate.
• color separation negatives are I made by photographing the subject on three separate prints or films through three standard color filters, namely, red, green and blue filters. Each of these negatives constitutes a separate record -of each of these primary colors. Positives are prepared from the color separation negatives and these positives are toned in the primary colors. The positive prints made from the red filter negative being toned. blue-green, the print from the green filter negative being toned magenta, and
• the positive to be toned magenta is transferred to a tray containing a treating bath prepared by mixing 20 cc. of fifteen per cent. solution of potassium ferricyanide with 100 cc. of a solution of the following composition:
• the tray containing the above treating bath is rockedto expel air-bubbles from under the film and'to insure rapid and uniform immersion of the film.
• the tray is then set aside until the first stage of treatment has been completed, which takes from fifteen to twenty minutes.
• the red developer preferably is prepared by mixing and heating together at about 50 C., for about thirty minutes, 30' grams of dimethylglyoxime, 750 cc. of triethanolamine, 250 cc. of monoethanolainine, and 500 of methyl or ethyl alcohol. Thereafter, there is added about 3500 cc.
• the red developer is poured off the film immersed therein and the film is then treated with a 25 per cent. solution of hypo for about five minutes. Thereafter, the film is washed with three or four changes of water, following which the film is immersed for a few seconds in a 1 per cent. solution of acetic acid and washed again with two or three changes of water. Thereafter, the resulting magenta print is ready for mounting.
• a soluble ferrlcyanide a soluble salt of an hydroxy aliphatic acid capable of forming a complex metal-acid ion, and thereafter immersing the print in a solution of a dioxime compound dissolved in a solvent comprising a water-soluble amine.
• soluble ferricyanide a soluble salt of an hydroxy aliphatic acid capable of forming a complex metal-acid ion, and thereafter immersing the print in a solution of a 'dioxime compound dissolved in a solvent comprising a. mixture of water-soluble aliphatic amines.
• the improvement which comprises immersing the .print in'an aqueous treating bath whose constituent ingredients include a soluble nickel salt, a soluble ferricyanide, a soluble salt of an hydroxy aliphatic acid capable of forming a complex metal-acid ion, and thereafter immersing the print in a solution of a dioxime compound dissolved in a solvent comprising monoethanolamine and triethanolamine.
• the improvement which comprises immersing the print in an aqueous treating bath whose constituent ingredients include a soluble nickel salt, a soluble ferricyanide, and asoluble salt of an organic acid which in solution will prevent the precipitation of nickel ferricyanide while allowing precipitation.
• nickel ferrocyanide selected from the group consisting of tartrates, citrates,
• aqueous treating bath whose constituent ingredients include a soluble nicket salt, a soluble ferricyanide, and a soluble salt of an organic acid which in solution will prevent the precipitation of nickel ferricyanide while allowing precipitation of nickel -ferrocyanide,. selected from the group consisting of tartrates, citrates, ,ox-alates, malates, succinates and benzoates, and
• aqueous treating bath whose constituent ingre-Q succinates and benzoates, and thereafter immersing the print in a solution of a color-developer comprising dimethylglyoxime dissolved in a solvent comprising a water-soluble amine capable of dissolving upward of one-tenth of 1 per cent.
• the improvement which comprises immersing the print in an acidified aqueous treating bath whose constituent ingredients include a soluble nickel salt, a soluble ferricyanide, a soluble salt of an organic acid which in solution will.
• improvement which comprises immersing the print in an acidified aqueous treating bathwhose constituent ingredients include a. soluble nickel salt, a soluble ferrlcyanlde, a. soluble salt of an organic acid which in solution will prevent the precipitation of nickel ferricyamde while allowing precipitation of nickel ferrocyanide, and a solvent for silver salts comprising potassium thiocyanate,

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Coloring (AREA)
• Pigments, Carbon Blacks, Or Wood Stains (AREA)
• Silver Salt Photography Or Processing Solution Therefor (AREA)

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• 0
  • US US223120D patent/USB223120I5/en active Pending
• 1936
  • 1936-02-05 GB GB3556/36A patent/GB469133A/en not_active Expired
  • 1936-02-17 FR FR806013D patent/FR806013A/fr not_active Expired
  • 1936-02-22 DE DE1936S0121675 patent/DE690608C/de not_active Expired
• 1939
  • 1939-06-20 US US280216A patent/US2231201A/en not_active Expired - Lifetime

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