US1290794A - Colored photographic element and process of making the same. - Google Patents

Description

s. E.SHE'PPARD.

COLORED PHCTOGRAPHIC ELEMENT AND PROCESS OF MAKING THE SAME.

APPLICATION FILED MAY 24. I911.

1,290,794, v V Patented Jan. 7,1919.

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SWZEW UNITED STATES PATENT OFFICE.

SAMUEL E. SHEPPARD, OF ROCHESTER, YORK, ASSIGNOR TO EASTMAN KODAK COMPANY, OF ROCHESTER, NEW YORK, A CORPORATION OF NEW YORK.

COLORED PHOTOGBAPHIG ELEMENT AND PROCESS OF MAKING THE SAME.

Application filed May 24, 1917.

To all whom it may concern:

Be it known that I, SAMUEL E. SHEPPARD, a subject of the King of Great Britain, and a resident of Rochester, county of Monroe, and State of New York, have invented certain new and useful Improvements in C01- ored Photographic Elements and Processes of Making the Same, of which the following is a specification.

My invention relates to colored elements for photographic purposes andprocesses of making the same, and more particularly to a translucid colored, finely divided or colloidal substance in a supporting medium capable of use on a photographic element or with photographically sensitive material in the art of photography. An object of my invention is to provide a colored medium for use on a hotographic plate, containing water fast co ored articles which will not bleed or migrate rom their carrier into adjacent materials during treatment theieof in the usual photographic baths and furthermore to furnish a preferably translucid me dium which is capable of being coated on a surface like a photographicemulsion and of being used as or mixed with photographic material for use ona plate, film, paper, or other surface; .VVith these and other objects in view, as will appear hereinafter from the following disclosure, my invention consists in the combination of parts and the steps of processes described in the specification and covered by the claims annexed hereto.

In accordance with my discoveries, I have found itdesirable to provide a colored medium for various photographic uses and especially to incorporate a dye or other color material in a medium capable of beingcoated photographically. Gelatin is ordinarily used for photographic coating purposes, but it is found, however, that if gelatin is dyed, there is a tendency for desirable types of dye to bleed or run, or to wander from the gelatin into aqueous solutions, so that the color is either discharged or is not permanently located and the colored mass is not well adapted for photographic, photomechanical or other purposes, since photographic intensity and definition are affected by the wandering of the dye. On the other hand cellulose compounds, such as nitrocellulose, cellulose acetate, etc. tend to hold basic dyes in molecular or a fixed relation thereto, and on this fact my discoveries are based. If nitro- Specification of Letters Patent.

Patented Jan. 7, 1919.

Serial No. 170,777.

do not ordinarily dye gelatin fast, except in the form of a precipitated dye lake obtained by the action of a mordant upon a dye, and such lakes have a tendency to sadden the colors and to affect the photographic properties of the gelatin.

' In accordance with my invention. I utilize as a dye carrying medium cellulose compounds such as cellulose acetates, nitrates, ethers, esters, etc, with or without, as may be necessary, such latent solvents as camphor, etc., and color the same by means of basic dyes, thus obviating the many disadvantages arising from dyeing gelatin, due to the presence of other substances such as alkali, or the difficulties of obtaining sharp photographic images arising from a wandering of the dye. I find it desirable to utilize a colloid, such as gelatin, as a basis for my colored medium, hence I mix therewith my color bearing elements. It is not feasible to incorporate a pigment in the gelatin for many reasons, including the facts that the pigment particles are of relatively large size and are opaque and reflecting and not sufficiently transparent to actinic light rays; but it is highly desirable that the dye carrier involve material having such properties that light may pass readily through it.

' I have found that nitrocellulose and similar compounds, besides being excellent dye carriers and translucid to actinic light, are capable of being emulsified or transformed into a state of fine suspension, so that when mixed with a supporting mass, such as gelatin, there is formed a color medium which is ractically homogeneous to the eye and.

which allows a substantially uniform passage throughout its mass of light colored according to the transmission of the dye, Colloidal materials are ideal for photographic emulsions, and I find it desirable to use such agglutinating colloids as gelatin, agar-agar, fish glue or water soluble colloids as the magma or holder of my colored particles. In order that the mixture may be uniform in composition, I find it desirable to finely divide or emulsify a mass of dyed cellulose compound in the colloid, such as an aqueous solution of gelatin, and thereby obtain an emulsion, similar to a photographic emulsion of silver bromid in gelatin, which may be coated or otherwise employed.

If nitrocellulose is selected for the color medium, I may dissolve it in a suitable solvent such as amyl acetate and color the nitrocellulose either before or afterby adding a dye thereto, depending on the nature of the latter, The nitrocellulose is then transformed from its dissolved state into one of a fine suspension or emulsion and incorporated with a colloidal or gelatinous carrier, while the dye remains Wash fast in the nitrocellulose and does not leave it during the intermediate chemical or physical changes. This step of incorporating one material with the other is accomplished preferably by the aid of an emulgent and stirring operations, after which the colloidal mass or emulsion thus formed may be suitably purified or I otherwise prepared for use. I thereby form an emulslon or suspension of more or less fine particles of partially gelatmized dyed nitrocellulose in a carrier. such as gelatin.

Dyeing the nitrocellulose.

In order to obtain dyed nitrocellulose, it is necessary to proceed in the manner indicated by the nature of the dye desired to be employed. Some dyes should be added to the nitrocellulose before it is dissolved in amyl acetate while others may be added to the acetate solution.

The dye which may be added to the cellulose derivative either before or after it is dissolved in the acetate. may comprise a basic dye or dyestuff soluble in oil, spirit, or both, and insoluble in water. For example, one may utilize the group of so called oil soluble dyestuffs comprising such dyes as Soudan dyes, e. 9., spirit soluble red O. G. as a red dye, orsuch dyes as malachite green, a green dye. If the dyestufi is oil soluble it may be directly dissolved in the amyl acetate solution of nitrocellulose; for example, a dye such as red O. G. is soluble in amyl acetate. Otherwise it is advisable that the dye be first dissolved, in a small quantity of alcohol, which may be mixed with the nitrocellulose solution in amyl aceate.

Variousmethods of converting water soluble dyes into spirit. soluble dyes may be employed depending on the chemical characteristics of the dye materials. For example, one may use a basic dye, which is insoluble in alcohol and soluble in water, but which forms a tannate with tannic acid, if the tannate is soluble in alcohol and insoluble in water. In case the use of a tannate is adopted the tendency of the gelatin to be tanned or insolublized may be avoided by treating the tannate with tartar emetic or potassium antimony tartrate or other solule antimony salts.

If an alcohol soluble dye, or an alcohol soluble compound thereof, such as a tannate, is used, I find it feasible to dissolve the same in alcohol and preferably a mixture of ethyl and methyl alcohol, of which the ethyl alcohol may be 95% alcohol. In other words, absolute alcohol need not be used.

I incorporate this alcohol solution with the acetate solution. The greater portion of the alcohol may be then distilled off, leaving the acetate behind.

If the so called hard nitrocellulose is employed as the dye carrier, it is quite feasible to dissolve it in acetone, or acetone and methyl alcohol, and then add the dyestutf thereto to color the material. Upon throwing this colored mass into hot water or otherwise treating it with hot Water, the dyed nitrocellulose is precipitated out, and all dye in excess stays in the acetone solution, provided an excess of acetone-alcohol and not too large an amount of dye is used. The precipitated dyed nitrocellulose may then be dried for subsequent treatment.

Dissoloiug the (lg ed nitrocellulose.

In order to dissolve dyed nitrocellulose, which may be obtained by the above described methods, it is desirable for the purposes of my invention to employ a substance which forms a solution capable of being emulsified. I*urthermore. the solvent should be normally insoluble in the water in which the gelatin is dissolved and normally indifferent to gelatin so as not to precipitate the latter from its solution. For this purpose amyl acetate is highly suitable. and the step may be carried out according to well known chemical operations.

By these or other methods serving to accomplish the same general result. I obtain a solution of a cellulose compound, as nitrocellulose, in a solvent such as amyl acetate, in which a suitable dye is incorporated. The dye is thereby fixed in a carrier which is capable of being finely divided into a more or less homogeneous mass without losing its color characteristics imparted to it by the dye.

Emulsif'yz'ng the (IF/(NZ solution.

In order to make an emulsion, suspension or a colloidal mass from this dyed compound, the amyl acetate solution of nitrocellulose is introduced into or incorporated with a solution of gelatin in such a manner that the nitrocellulose assumes a finely divided or colloidal condition and remains suspended in or mixed with the gelatin which serves as a carrier for the dyed particles.

To facilitate the operation of emulsifying or transforming the nitrocellulose intoa colloidal condition, the use of a suitable emulgent is desirable. For this purpose I prefer to employ Turkey red oil, 71. 6., sulfonated castor oil, and may adopt any Well known method of producing the emulsion. For example, the solution of dyed nitrocellulose may be introduced, as by an atomizer, in a state of fine subdivision into the gelatin solution and the mass agitated until the emulsion has been formed, the solution being kept liquid by maintaining the temperature above the setting point of the gelatin. Regulation of the temperature controls the viscosity of the solution and thereby is of marked importance in determining the size of particles to be obtained. If desired, the emulsion may be homogenized in its present oily stage, in order to obtain colloidal particles of uniform size, this operation being carried out by any suitable well known means. For example, one may throw the emulsion against bafl'le plates by centrifugalforce, thus causing the particles to assume sizes that are more or less of the same order of magnitude. I

As a specific example of the above steps of my process, I may take 3 grams of the solid dyestuif, spirit soluble red O. G., and dissolve this in a solution of 5 grams of hard nitro cotton in 100 cc. of amyl acetate. This solution is introduced slowly from below into 500 cc. of 10% solution of gelatin in Water containing 5 cc. of Turkey red oil, the solution being kept liquid at from 50 C. to 60 C.

Uurdling the emulsion.

This mass thus obtained whether homogenized or not, may be considered as made of a supporting medium of gelatin containing particles of nitrocellulose carrying dye and oil, the oil comprising the emulgent and the amyl acetate solvent employed in the process. These particles of dyed nitrocellulose, containing oily material, will not mix satisfactorily with other materials such as a silver bromid emulsion: hence I find it highly desirable to decrease the material, or to remove the larger portion of the amyl ace tate solvent as well as the oil emulgent from the nitrocellulose particles, and thereby obtain a mass of gelatin containing fairly pure semi solid particles of nitrocellulose intimately associated with a dyest-uff. Thismay be acomplished by coagulating or curdling the gelatin of the emulsion maintained as a sol or liquid by proper regulation of temperature. by adding it to an excess of electrolyte as. 1'. 11.. a strong saline and preferably alkaline solution. For example. I may use equal volumes of saturated sodium sul- 'in gelatin, which has thus been converted from the hydrosol to the hydrogel condition. Purification of cards and formation of sol.

The gelatin, when curdled or brought into the gel condition, drags down or entrains globules of the nitrocellulose; but these nltrocellulose particles are substantially unaffected by the curdling operation, except in so far as the elimination of amyl acetate solvent tends to stabilize the particles and reduce their tendency to run together or be deemulsified. By this method. the nitrocellulose particles are purified from a large part of the oil, since the latter remains largely in the solution, the gelatin and nitrocellulose being thrown down into a state comparable with a precipitated salt and separable from the oil and salt solution by filtration or other suitable methods. While the main part of the oily matters, including the amyl acetate and the Turkey red oil remain suspended in the salt solution and can easily be separated from the curds, yet a portion of the saline solution and some of the oil remain mechanically entrapped in the curds. These impurities may be removed by suitable methods, such as by pressure, or the curd may be removed from the saline. bath, melted, filtered and then reset. In any case. the curd or curdled emulsion is finally washed in a cold very dilute acid such as sulfuric acid to neutralize the alkalinity of the mass, and then in ice water, to remove the excess of neutral salts and oily matters.

In order to put the material back into the sol condition, the curd or coagulum is melted in a water bath and if required its concentration is adjusted. to thin or thicken the gel and form a uniform suspension by an addition of water or gelatin as is required. The mass is then filtered. if necessary, through felt or the like to remove any scum. if such be present, although it may obviously be separated by any suitable method. such as skimming, straining. filtering. etc. This step in the process tends to homogenizc the suspension or emulsion. since only th finer particles get through the. filter. depending. of course. upon the. size of the filter openings.

There is thus obtained a uniform. stable emulsion or suspension. depending on the condition of the particles, of more or less partially gelatinized nitrocellulose in gelatin. the particles of the, mass being more. or less permeated with dye. which is in a fixed relation with the nitrocellulose and will not wander or bleed. In other Words, the dye in the nitrocellulose particles is wash fast, al-

though not necessarily light fast, as regards treatment with water and such other chemicals as are ordinarily used in photographic operations.- The state of suspension or the size of the colloidal particles may be controlled by modifying the conditions of the emulsification, heat treatment before and after curdling, etc., it being possible to obtain an emulsion in which the suspension is grainless or colloidal in state or in which the dyed material is present in grains varying from fine to the coarser sizes. For example, the grain size may be increased by a continuation of the heat treatment during the melting operation after the gelatin has been curdled. Furthermore, the transparency of the mass may be controlled to a certain degree, since the fine grained emulsion is more transparent than the coarse grained. The processes of making this emulsion, as described, do not alter or affect materially the properties of' gelatin of value in the photographic field, such as solubility in hot water and permeability to solutions of photographic chemicals, as well as its desirable qualities whereby it may serve as an elastic carrying and binding medium for silver salts.

Formation of color plate.

. Having thus prepared an emulsion of dyed nitrocellulose in gelatin, I may coat this emulsion by any suitable method on a transparent film or plate in any desired manner, as indicated in the illustrative ex amples shown in the accompanying drawing in which Figures 1 and 2 are sections of sensitive photographic elements to which a sep arate color layer is applied; Fig. 3 is a section of a photographic element in which the color and sensitive emulsions are incorporated in one layer; Fig.- 4 a color screen with a color field extending over the entire surface; and Figs. 5 and 6, color screens in which the color or colors are applied in some design.

In the figures, A indicates the support made of any suitable material; B a uniformly applied color layer made in accordance with my invention and C a sensitive emulsion; BC indicates a layer in which the sensitive and color materials are in one layer; B indicates a single layer applied in a design and B a multicolor layer applied in a design.

The emulsion made as above described may be applied either throughout the entire surface of the element as shown in Fig. 4 to serve as a ray filter or in separated areas in volving a dot, line or other configuration as shown in section in Figs. 5 and 6 for use as a screen plate, or f r various photographic purposes, where a colored medium can be used on a transparent or opaque support,

such as glass, film or paper. Similarly, the dyed emulsion may be undercoated, as in Fig. 1, or overcoated, as in Fig. 2, on a support beneath or over photographic material, such as a layer of silver salt emulsion, in any desired configuration or throughout the entire surface of the support. To produce, for example as in Fig. 2, a photographic plate combined with a green ray filter, a plate A suitably coated with a silver-salt gelatin emulsion C may have applied over the silver salt a layer of my emulsion B, which has been dyed by means of malachite green. It is also feasible to miX my dyed emulsion with a sensitive emulsion, such as silver bromid in gelatin, and so incorporate the dyed material in intimate association with the sensitive substance, and thereafter coat a photographic support A with the mixture BC, which may be utilized in the art of color photography for the production of color pictures.

Having thus described my invention, What I claim as new and desire to secure by Letters Patent is:

1. Photographic material comprising finely divided color particles insoluble in the ordinary photographic baths, dispersed throughout a carrying medium.

2. Colored photographic material comprising a colloidal medium, permeable to water and to photographic solutions carrying finely divided, colored, translucid particles dispersed therein.

3. Photographic material comprising an emulsion of translucid material containing a water fast, nonmigratory dye.

4. A photographic element comprising a support and a coating thereon of an emulsion of fast dyed particles in a water soluble colloidal medium, said particles being unaffected by photographic developing solutions.

5. A photographic element comprising a support and a colloidal mass containing finely divided translucid particles having intimately incorporated therewith a water insoluble color material, which will not migrate from the particles to the surrounding medium. v

6. Photographic material comprising a colloidal medium, permeable to water and to photographic solutions carrying emulsified, oil free, colored translucid particles.

7. A photographic element comprising a support and a mono-color coating of an emulsion of translucid, mono-colored, oil free particles thereon.

8. A photographic element comprising a support and a coating of a colloidal magma incorporating therewith an emulsion of translucid particles and a color material which will not Wander from said particles to the colloidal magma.

9. A photographic element comprising a support and a translucid colloidal medium containing emulsified particles of, translucid material carrying a water fast dye associated therewith, which will not wander therefrom into the colloidal medium.

10. A photographic element comprising a support and an emulsion in a carrier of gelatin of translucid material incorporating a dye, said material having a greater afiinity for the dye than has the gelatin;

11. A photographic element comprising a support and a colloidal magma carrying a finely divided cellulose compound therein.

12. A photographic element comprising a support and a colloidal magma carrying emusified nitrocellulose therein.

13. Photographic material comprising gelatin and emulsified nitrocellulose therein.

14. Photographic material comprising a supporting. medium of gelatin carrying finely divided particles of dyed nitrocelluose.

15. Photographic material comprising a supporting medium of gelatin carrying emulsified particles of nitrocellulose having incorporated therewith a dye stuff.

16. A photographic element comprising a support and a coating of a supporting medium of gelatin carrym a mono-color dyed sus ension of nitrocell ose.

1 A photographic element comprising-a support and p otographically sensitive material and an emulsion of color particles thereon.

18. A photographic'element comprising a support carrying photographically sensitized material and a colloidalmagma containing finely divided translucid color particles thereon. a

19. A photographic element comprising a support, hotographically' sensitive material and a col oidal ma a containing emulsified translucid matera incorporating a water fast dye which will ,not wander to the magma.

20. A photographic element comprising a support, photographically sensitive material and a colloidal magma containing emulsified nitrocellulose particles.

21. A photographie element comprising a support, and photographically sensitive material and an emulsion of'translucid particles of colored nitrocellulose in gelatin on said support.

22. A mono .color photographic element comprising a support and photographically sensitive material and a mono-color emulsion of nitrocellulose and dye stuff in gelatin on said support.

23. The process of manufacturing photographic material comprising the steps of colorin a substance capable of being finely divi ed, and finel dividingthe colored substance in a colloi al medium.

24. The process of. making photographic.

atin solution.

26. The process of making photographic material. comprising the step of emulsifying a cellulose compound in a suspending medium.

27. The process of manufacturing a colored element comprising thesteps of incorporating a dyestuff in a cellulose compound, and emulsifying a solution of sai dyed compound in a colloidal medium.

28. The process of making photographic material comprising. the step of emulsifying nitrocellulose in a colloidal medium.

29. The process of making photographic. materialcomprising the steps of colorin nitrocellulose and emulsifying the colored material in gelatin.

30. The process of making photographic material comprising the steps of dissolving nitrocellulose in a solvent and adding color to the nitrocellulose and then emulsifying in an aqueous gelatin solution.

31. The process of making photographic material comprising the steps of dissolving nitrocellulose in amyl acetate and incorporating a color with the nitrocellulose and then emulsifying the colored nitrocellulose in an aqueous gelatin solution.

32. The process of making a photographic material comprising the steps of forming'a.

thesame in gelatin and purifying the emu sion.

solution of nitrocellulose, emulsifyin 33. The process of making photographic material comprising emulsifylng colored ni trocellulose in an aqueous gelatin solution,

and homogenizing the emulsion to obtain uniformly sized particles.

34. The process of I forming a photographic element comprising emulsifying colored nitrocellulose in gelatin and coating 9. support therewith.

35. The process of preparing a colored photographic element comprising dissolving. nitrocellulose in amyl acetate, incorporating a water fast dye with the nitrocellulose, emulsifying the same in an aqueous gelatin solution and coating a support with the colored emulsion of nitrocellulose in gelatin.

36. The process of making photographic material comprising the steps of dyeing nitrocellulose, agitating a solution of the nitrocellulose in amyl acetate in the presence of an emulgent and aqueous gelatin while material comprising the steps of dissolving nitrocellulose in an oily solvent, incorporating color material therewith, emulsifying the solution in an aqueous gelatin solution, curdling the emulsion to remove oily sol vent therefrom and reforming the sol condition of the emulsion.

38. The process of making photographic material comprising the steps of forming a solution of nitrocellulose in amyl acetate, emulsifying the same in an aqueous gelatin solution, changing the gelatin from the hydrosol to the hydrogel condition, removing amyl acetate therefrom and reforming the sol, to produce an emulsion of nitrocellulose in aqueous gelatin.

39. The process of making photographic material comprising dissolving nitrocellulose in amyl acetate, addin thereto an alcoholic solution of a, dye which has a molecular aflinit for nitrocellulose and will not wander therefrom into gelatin or into the ordinary photographic solutions, emulsifying the'dyed nitrocellulose in a colloidal solution of gelatin, adding an electrolyte thereto to curdle the gelatin colloid to form a gel, removing the bulk of the amyl acetate solvent therefrom, and reforming the sol condition of the colloid, thereby obtaining a colloidal mass of gelatin carrying finely divided colored particles of nitrocellulose dispersed therethrough.

40. The process of making a photographic element comprising the steps of coloring nitrocellulose with a dye which normally tends to wander from elatin into nitrocellulose, and dissolving t e nitrocellulose in an oily solvent, then emulsifying the nitrocellulose in a colloidal medium, removing the oily solvent and purifying the emul- 40 sion and coating said emulsion of dyed nitrocellulose in its. colloidal carrying medium on a photographic element.

41. The process of making photographic material comprising the steps of incorporating an alcoholic dye solution with nitrocellulose, emulsifying a solution of nitro' cellulose in an aqueous gelatin solution by agitating in the presence of an 'emulgent to form a hydrosol, adding an electrolyte to the hydrosol to form a gel containing suspended nitrocellulose, removing impurities therefrom, melting the gel to reform the hydrosol and adjusting the concentration by adding water or gelatin as required.

Intestimony whereof, I have signed this specification in the presence of two witnesses this 22d day of May, 1917, at Rochester, N. Y.

SAMUEL E. SHEPPARD.

Witnesses:

FRED H. GARDNER, C. E. MARTIN.

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