US2096617A

US2096617A - Manufacture of photographic film

Info

Publication number: US2096617A
Application number: US27916A
Authority: US
Inventors: Gale F Nadeau
Original assignee: Eastman Kodak Co
Current assignee: Eastman Kodak Co
Priority date: 1935-01-12
Filing date: 1935-06-22
Publication date: 1937-10-19
Anticipated expiration: 1954-10-19
Also published as: BE416158A; FR47560E; GB477153A; FR49753E; DE713839C; GB478357A; GB513694A; GB477289A; US2096616A; US2096675A; DE711190C; BE413245A; FR800517A; GB470565A; US2135524A; DE697157C

Description

Get 19, 1937 I e. F. NADEAU 2,096,517

MANUFACTURE OF PHOTOGRATHIC FILM Original Filed June 22, 1955' 2 Sheets-Sheet 1 0 SENSITIVE EMULSION B I GELATIN SUB 1 xcawwss NITRATE OI? ACETATE UNDERCOAT x FORMALDEHYDE-ARYL SULPHAMIDE RESIN UNDERC'OAT A cEI.LuI.osE DERIVATIVE SUPPORT FORMALDEHYDE'ARYL SULPHAMIDE RESIN UNDERCOAT CELLULOSE ACETATE PROPIONATE SUPPORT D 5 3 sENsITIvE EMULSFON .X MIXED GELATIN&FORMALDEHYDE-APYL SULPHAMIDE RESIN SUB CELLULOSE ACETATE OR ACETATE @cii. 19, 19370 a. F. NADEAU MANUFACTURE OF PHOTOGRAPHIC FILM 2 Shets-Sheet 2 Original Filed June 22, .1955

0 I IIIIIIIII Q lliililli l n dim Patented Oct. 19, 1937 UNITED STATES 2,096,617 MANUFACTURE OF PHOTOGRAPHIC' FILM Gale F. Nadeau, Rochester, N. Y., assignor, by 'mesne assignments, to Eastman Kodak Company, Jersey City, N. J., a corporation of New Jersey Application June 22, 1935, Serial No. 27

Renewed March 30, 1937 18 Claims.

This invention relates to photographic materials and more particularly to photographic film having a high degree of flexibility and satisfactory emulsion adherence characteristics in which an improved type of substratum or undercoat is employed between the light-sensitive emulsion and the film support.

This application is in part a continuation of my co-pending application, Serial No. 1547, filed January 12, 1935.

In the manufacture of photographic film, especially film of the so-called safety type, in which a light sensitive emulsion is coated onto a flexible, relatively uninfiammable cellulose derivative support, two rather serious problems are encountered. One is to get the emulsion to stick properly to the support, and the other is to attain the requisite degree of flexibility. When the adhesion is good, the film as a whole is often brittle and will fracture even with moderate bending. This is probably due to the fact that, since the emulsion adheres so closely to the support, it is, broadly speaking, substantially continuous with it. Accordingly, as soonas the emulsion breaks, the energy of impact produced by the fracture is transmitted directly to the support and causes it to break also. Experience has shown that when the emulsion adheres less tenaciously to the support, the film is often found to have unsatisfactory stripping qualities, that is, the emulsion can be lifted. or stripped from the base or support too readily to meet the requirements of many photographic uses. It has accordingly always been found necessary heretofore to efiect some sort of compromise between adherence on the one hand and brittleness on the other, and it is well known that one property always invariably gained at the .expe'nse of the other.

As is well known, gelatin emulsions .(which are colloidal solutions or dispersions of gelatin in water) cannot be made to adhere directly to a cellulose derivative support, because water will not wet this type ofsurface; It is accordingly necessary to apply to the cellulose derivative support a thin layer, substratum, or sub, as it is generally called, of gelatin in order to provide a surface to which the emulsion" will stick.-

55 the gelatin thereto. Once the gel sub is applied,

it is a relatively simple matter to'make the lightsensitiveaqueous emulsion stick to the support, since water will readily wet and soften the surface of the gel coating and the emulsion can thus be made to adhere to it. v

It should be pointed out that when an emulsion is applied to a gel-subbed base, the emulsion and gel sub tend to merge and form what, for all intents and purposes, may be considered a single continuous gelatin layer on the film, and that the degree of adherence of the emulsion to the support is dependent'upon the degree of adherence of the gel sub to the support or to the intervening substrata if any. This adherence of the gel sub is controlled in practice by controlling the strength of the gel subbing solution, that is, the

solvent or softening power of the subbing solution on the cellulose derivative material or intervening substrata. This control of solvent or softening power of the solution is accomplished by regulating the kind-or amount of each of the solventsused in compounding. .it. A strong gel subbing solution is, accordingly, one which has a relatively strong solvent, softening or swelling action on the support, material and causes the deposited gel sub to adhere tena ciously thereto, while a weak subbing solution is I one which is only weakly solvent with respect to' the support material and will cause the deposited gelatin coating to adhere only slightly. In general, it may be said that the stronger the gel subbing solution, the greater will be the degreeof adherence of the sub to the support and the greater the brittleness of the completed film.

The problem of obtaining proper adherence of r the emulsion without an undue increase in brittleness is a. difficult one, especially when dealing with the so-called safety types of films in which the support is formed from a cellulose organic derivative, such as cellulose acetate. When employing cellulose nitrate as the support, it is possible to use a relatively weak gel subbing solution and thus, to a certain extent, to keep the adherence (and consequently brittleness) down to approximately .the proper value, but with cellulose organic derivative supports, such as those formed of cellulose acetate, or cellulose acetate propio nate, for example, much stronger subbing solutions must be employed with the result that excessive adherence, and therefore excessive brittleness occurs. It has accordingly been necessary with this latter type of support, first to apply a thin cellulose nitrate sub (which can itself be subbed with relatively weak subbing solutions); and then to apply a gel sub to the nitrate surface,

followed by the emulsion coating, but this is disadvantageous because of the fact that it introduces a certain amount of cellulose nitrate into the finished film, making it difflcult to meet the underwriters specifications for safety film. Aside from this attempted solution of the problem the question of brittleness (where emulsion adherence was satisfactory) has remained substantially the same, and even films including nitrate undercoats have proved insufliciently free from this defect to meet all of the rigid requirements of cinematographic use. t

In an attempt to solve this problem of obtaining proper flexibility without an undue sacrifice of emulsion adherence, it has been proposed to employ an extra heavy cellulose nitrate undercoat underneath the gel sub and, while this expedient does appreciably increase flexibility, without an extra large decrease in adherence, it suffers the disadvantage pointed out above, namely, that it introduces a relatively large amount of cellulose nitrate into the finished product. Many other expedients looking toward the same end have been employed, for example, the use of anundercoat .of rubber or similar material, but'it has been foundthat, similarly to cellulose derivative undercoats, the impact arising from rupture of the emulsion is transmitted through the rubber layer, causing it to break, and this break is carried on into the material of the underlying support.

Somewhat similar to such products, and 'sulfering many of the same defects, are various laminated structures in which bases consisting of cellulose organic derivatives or other materials have applied thereover a layer or layers of resinous or rubber-like materials of substantial thickness, these layers constituting a material part of the support and being applied, either in the form of separate sheets united to the base by appropriate cement, or deposited, as coatings, from appropriate solutions.

It is the principal object of the present invention to overcome the above-mentioned prior art diiilculties and to provide a photographic film having a high degree of flexibility or freedom from brittleness and at the same time satisfactory emulsion adherence. A further object is to provide an improved type of safety film. in which fieidbility is rendered completely independent of the degree of adherence. A further object is to provide an improved type of safety film in which flexibility is rendered completely independent of the degree of adherence between the emulsion and the underlying substrata. A specific object is to provide a film having a; formaldehyde-aryl sulphamide resin sub brundercoat between the light-sensitive gelatin layer and the film base.

-Other objects will appear hereinafter.

I have found that if the support is first coated with a thin layer consisting essentially of a synthetic resin of the type sold under the trade name Santolites which are products obtained by the interaction of formaldehyde or a polymer of formaldehyde with an aryl sulphamide or an alkyl N-substituted aryl sulphamide, almost any strength of gel subbing solution may be employed in the subbing operation and the gelatin emulsion may be bound to the gel sub and other substrata as tightly asdesired without giving rise to brittleness in the finished film. In other words, the use of these resins as undercoats renders the matter of flexibility independent, of the degree of adherence between the emulsion and the underlying substrata.

Inthe accompanying drawings, Ihave illustrated in greatly exaggerated section several film structures produced in accordance with my invention, and a test by which the flexibility of such films may be determined.

Figs. 1, 2, and 3 are sections through the body of a photographic film produced in accordance with my invention and including a formaldehydearyl sulphamide resin sub.

Figs. 4 and 5 illustrate the manner of carrying out a brittleness test as described herein.

*Figs. G and '7 illustrate the behaviour of a relatively brittle film when subjected to the test illustrated in Figs. 4 and 5.

Figs. 8, 9, and illustrate the behaviour of a film such as shown in Figs. 1, 2, and 3 respectively,

upon being subjected to the test illustrated in Figs. 4 and 5.

In the following examples and description, I have set forth several of the preferred embodiments of my invention, but they are included merely for purposes of illustration and not as a limitation thereof.

After carrying out extensive work with various types offresinous materials, I have found that in order to fulfill the requirements of use as a substratum in the photographic film, the resin must be suificiently adhesive when dissolved in appropriate solvents to stick properly to the cellulose derivative material of the support, that is, so that the completed film will pass the stripping tests herein described. The material must be compatible with the cellulose derivative and must alsd be compatiblewith the photographic emulsion in the sense that it shall not fog or reduce the sensitivity thereof or adversely affect any of the various processing steps to which the film is subjected during development. All of these requirements I have found are fulfilled by the formaldehyde-.aryl sulphonamide resins.

The particular resins which are used as sub- .layers according to -my invention are colorless odorless products-soluble in benzene and acetone, obtained by the interaction of formaldehyde or polymers of formaldehyde with an aryl sulphamide or an alkyl N-substituted aryl sulphamide and 'are manufactured and sold by the Monsanto Chemical Company under the trade name Santolites. Their preparation is described on pages 177-178 of the text by Scheiber and Sandig entitled Artificial resins, published in 1931 by .Isaac Pitman 8: Sons, .Ltd., London, England, and more particularly in German Patents 359,676; 369,644, British Patent 349,956, and

U. S. Patents 1,907,554 and 1,908,159. Probably.

the most typical resin is the product of interaction of paratoluene sulphoethylamide with formaldehyde.

The subbing of the film support with the resin solution'may be carried out by any technique well known to those skilled in the art. The material may be conveniently applied to a cellulose acetate support, for example, from a 2% to 10%,

the well known subbing operations, such as immersion, bead application, or otherwise. The material may be subbed on one or both sides, depending upon the type of film being produced.

For example, in the manufacture of portrait film, it is customary to apply a layer of gelatin to the surface opposite the emulsion and in X- ray film to apply gelatin subs and emulsion to both surfaces in order to give greater flatness to the product and for other purposes. In accordance with my invention the support or'fllm base is subbed on both surfaces with the resin in producing this type of product.

Example 1 In producing a film in accordance with one form of my invention, a support consisting of a sheet or film of cellulose acetate is led through an immersion type hopper containing a 10% methyl or ethyl alcohol solution of a formaldehyde-aryl sulphamide resin of the type herein described at alinear speed of approximately 3 feet per minute. The support is then led through an appropriate drying apparatus maintained at a temperature of approximately 120-200" E, where the solvent is evaporated from the surface of the material and a resin layer of approximately .00008 inch in thickness is deposited thereon. The resin-coated material is then carried through a second immersion type hopper containing a solution of a cellulose derivative say, a 2 &% solution of a high alcohol-soluble, low viscosity nitrocellulose dissolved in a solvent comprising 90% of methyl alcohol and 10% "of butyl position:

a v Per cent by weight Gelatin; 1.0

Water n 10.0 Acetic acid 0.5 Methanol 88.5

The gelatin-coated material is then dried at an appropriate-temperature and the usual gelatino-silver halide emulsion coating deposited on the gelatin surface in a well known manner, thus completing the film. v

Example 2 7 Per cent by weight Gelatin 1.0 Acetic acid 1.0 H20 M n 4.0 Methyl alcohol 30.0 Acetone L 64.0

After drying the gelatin layer, the light-sensitive emulsion layer is deposited on the film as before.

Example 3 A sheet or film of cellulose acetate or cellulose acetate propionate of appropriate thickness is coated with an extremely thin layer comprising a mixture of gelatin and a formaldehyde aryl sulphamide resin, this coating being deposited from a solution having approximately the' following composition:

Per cent by weight Gelatin 1.0 Formaldehyde-aryl sulphamide resin 1.0 Acetic acid 1.0 Acetone 50.0 Methyl alcohol 43.0 Water 4.0

After appropriate drying of the gelatin-resin,

coating, the emulsion is applied to the resinsubbed surface of the support in the usual manin fact, almost any of the cellulose ester compositions customarily used for film making purposes. Likewise, the material of the support may be composed of any suitable cellulose organic derivative material, such as cellulose acetate, cellulose propionate, cellulose butyrate, or a mixed cellulose organic ester, such as cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate stearate, and the like. Although not limited thereto, my invention relates primarily to the manufacture of the so-called safety types of photographic film in which the support is composed of a relatively non-inflammable material, such as the cellulose organic esters; since it is with this type of material that the problem of brittleness is most severe.

Although in the above examples, I have found erence to photographic films coated or subbed on one side only, the use of the formaldehydearyl sulphamide resins as subs as herein described, may be applied with equal success to products, such as X-ray or portrait film, in which gelatin or emulsion coatings or both are deposited on both surfaces to give greater flatness to the film. It will be apparent that in such products, it is as necessary to prevent brittleness arising from theapplication of thegelatin on one side of the film as on the other. I have found that brittleness is as effectively prevented by the use of the thin resinous layers in accordance with my invention as in the case of those films which have gelatin layers or coatings on one surface only.

The customary tests by which the properties of my improved type of photographic films are determined will now be described. These ale the so-called dry stripping, wet stripping, and brittleness or flexibility tests.

The dry stripping test is carried out as follows: A piece of the complete emulsion-coated film of. a convenient size, say, 6 inches wide by 40 inches long, is held at one end with both hands with the emulsion side toward the operator and is then torn lengthwisewith successive quick motions of one hand, the tearing generally being carried out at a slight angle to the edge of the strip in order to obtain an oblique tear. The tears thus produced are more or less jagged. An attempt is now made to pullback the emulsion coating from away from the support to a certain extent.

when no peeling, or substantially no the film with the fingernails and the degree to which the emulsion separates from the support is a measure of its adherence. It will, of course, be understood that the standards of emulsion adherence will vary for different types of film and what is considered satisfactory for one film may not be satisfactory for another. For example, stripping (emulsion adherence) is said to be satisfactory for X-ray film if the emulsion cannot be stripped back more than three or four inches. For Cine film, on the other hand, the stripping should not be greater than about of an inch.

The wet stripping test is carried out as follows: A strip of the emulsion-coated film of convenient size is soaked in water at 70 F. for ten minutes. It is then removed from the water and fixed on a flat surface with the emulsion side up. The emulsion is then gouged or creased with the fingernails at points near the middle and end of the strip, each nail scratch tearing the emulsion The scratched places. are then rubbed with considerable force with the balls of the fingertips for several seconds. A film is said to have satisfactory wet stripping (emulsion adherence) properties the emulsion occurs as a result of this rubbing action. Wet stripping is said to be unsatisfactory when an appreciable or large amount of the emulsion comes off. For most types of film it should not be possible to remove pieces wider than V inch by this test.

The brittleness test is carried out as follows: A strip of film of convenient size is heated for forty-five minutes in a brittleness oven in which air having a controlled relative humidity of 20- 25% and a temperature of 1l0-120 F. is circulated. The film is then removed from the oven and folded at ten difierent places along the strip by pressing the fold suddenly between the forefinger and the thumb. If the fllm is brittle, this sudden folding will cause it to break or snap in two at the fold. The in terms of freedom from brittleness which may be figured directly in percentages from the results of the test. For example, a film is said to be free from brittleness if it ruptures at only four out of ten folds.

m invention will be further understood by reference to the accompanying drawings. In Fig. 1 I have illustrated a section through a photographic film produced substantially as described in Example 1 in which the letter A designates a cellulose derivative support composed of cellulose acetate, for example. Superimposed on and tightly adhering thereto is an extremely thin undercoat composed of a Santolite (formaldehyde-aryl sulphamide resin), this underccat being approximately .00008inch in thickness. B designates a thin protective layer of cellulose nitrate or cellulose acetate, while C is a thin gelatin sub which adheres to the cellulose nitrate or acetate layer B. D is the final gelatino-silver' halide emulsion layer which. adheres tightly to the gelatin sub C.

Fig. 2 represents a film structure prepared as described in Example 2 and difl'ering from that of Fig.1 in that the protective layer of cellulose derivative B has been omitted, it being one of the features of the formaldehyde-ml sulphamide. resins that they may be conveniently handled without a protective coating. due to the fact that they are not tacky at ordinary temperatures or the temperatures customarily met with in film manufacture.

peeling, of

flexibility may be defined Fig. 3 represents a film structure similar to that of Fig. 2 except that the gelatin layer or sub has been omitted and a. single layer X composed of a mixture of gelatin and a formaldehyde-aryl sulphamide resin has been deposited upon the support and the emulsion layer D laid down directly upon this gelatin-resin layer.

Figs. 4 and 5 illustrate graphically the manner of carrying out the brittleness test above referred to. The film F, after removal from the brittleness oven, is folded at a given place into the form of a short loop, the gelatin layer D being outermost. This loop is then closed by means of the forefinger and thumb. The pressure being applied as suddenly as possible and in the direction indicated by the arrows in Fig. 5. v

In Figs. 6 and 7 there are illustrated the results obtained when an ordinary type of photographic film comprising-a support A, athin cellulose derivative undercoat, and the emulsion layer D over the gel subis subjected to the test. It will be seen that the crack starting in the emulsion penetrates through the layers B and C and goes on into the material of the support. This crack almost invariably continues on through the support with the result shown in Fig. '7. The film here illustrated is a typical prior art product and one from which the resinous sub or undercoat of the present invention is absent. This product is also one in which there is a. high degree of adherence between the emulsion and the gel sub layer and between these layers and the underlying cellulose derivative material. I

Fig. 8 illustrates the results obtained when a film employing the resinous subs or undercoats of my invention is subjected to the test illustrated in Figs. 4 and 5. This film is in all respects the same as that illustrated in Figs. 6 and '7 except that a layer X of a'Santolite (formaldehyde-aryl sulphamide resin) has been applied to the support before application of the cellulose derivative layer B, the gel sub C, and the emulsion coating D. The emulsion is made to adhere to the support with the same degree of tenacity, as in the product illustrated in Figs. 6 and 7, but the product of Fig. 8 differs from that of Fig. 6 in the fact that, although the crack starting in the emulsion may continue through the gel sub, the cellulose derivative sub and even the resin layer itself, it does not in any case, penetrate into the support itself.

Figs. 9 and 10 illustrate graphically the results obtained in subjecting the film structures of Figs. 2 and 3, respectively, to the test illustrated in Figs. 4 and 5. In the structure of Fig. 2 the crack starting in the emulsion layer penetrates the gelatin and resin sub-layers but does not penetrate the support itself. A similar result is obtained with the product of Fig. 3 as illustrated in Fig. 10.

Figs. 8, 9,and 10 strikingly illustrate the fact that a photographic film produced in accordance with my invention is characterized by the unusual property of freedom from brittleness or, in other words, it has 100% flexibility. In addition to this remarkable property, films produced in accordance with my invention respond satisfactorily to both the wet and dry stripping tests above described. In this connection, it should be pointed out that one of the outstanding features of my invention is the fact that the adherence of the emulsion may be regulated without regard to the flexibility of the film. In other words, it is possible to produce a film in which the emulsion adheres-to the support with the highest practicable degree of tenacity without inducing any brittleness whatever in the film as a whole or causing the'support material to break on bending, either during cinematographic or other use, or when subjected to the tests herein described.

While I offer no particular explanation of theory to account for the unusual resultsob- -tained in the practice of my invention it'is evident that the resinous subs or undercoats herein described offer some means of dissipating the impact of the rupturing emulsion. This effect is to be distinguished from the mere cushioning effect characteristic of elastic or semi-elastic materials. In many, although not all, cases, the break occurring in the emulsion will penetrate even the lowermost resinous layer, and these layers may even be released from the support, to a slight extent, but in no case does the break penetrate the material of the support itself. a

In the above description and in the claims I have used the terms substratum, sub layer, or su subbing, undercoat, etc. By a substratum, sub layer or sub I refer broadly to any layer, whether composed of a single layer or a plurality of layers, employed between the emulsion and the film base. The term undercoa refers to a single layer used underneath any other layer except the emulsion. It is customary, however, in the case of a plurality of layers underneath the emulsion to refer to the layer next to the emulsion as a sub and the underlying layers as undercoats. The term snubbing is employed broadly to indicate the application of a thin layer of a material to the surface of a film, whether previously coated or not.

Furthermore, by the term sub 1 refer to extremely thin layers or undercoats of material of the order of only a few millionths of an inch in thickness, such,-for example, as the resin layer of Example 1. Inasmuch as the thickness of these layers is of this extremely small order of magnitude, it is evident that it may vary by a number of millionths, either above or below the preferred thickness of .00008 inch. It will also be evident that the thickness of these subs will vary in accordance with the usual variations met with in the type of film base used. The thicker types of film base tolerate a slightly thicker sub, although in no case is the thickness sufiicient to be regardedas a lamination in the ordinary sense of the word as in those cases where a laminated film base is built up by the superimposition of a number of layers of appreciable or relatively substantial thickness.

What I claim is:

1. A photographic film of satisfactory flexibility and free from brittleness, comprising a cellulose organic derivative support and a photographically sensitive colloid layer adhesively joined to the support by a composite intervening layer comprising an extremely thin sub composed of a resin formed by the condensation of formaldehyde or polymers of formaldehyde with a member of the group consisting of the aryl sulphamids and the alkyl N-substituted aryl sulphamids adhesively joined to the support, a cellulose derivative sub graphically sensitive colloid layer adhesively joined to the support by a composite interveninglayer comprising an extremely thin sub composed ofa resin formed by the condensation of formaldehyde or polymers offormaldehyde with an alkyl N-substituted aryl sulphamid, adhe sively joined to the support, a cellulose derivative sub adhesively joined to the resin sub and a gel sub adhesively joined to the cellulose deriva' tivesub and to the sensitive colloid layer, said intervening layer rendering the flexibility characteristics of the film as a whole independent of the degree of adhesion existing between the photo'graphically sensitive layer and the subbed support. I

3. A photographic film of satisfactory flexibility and free from brittleness, comprising a cellulo'se organic derivative support and a photographically sensitive colloid layer adhesively joined to the support by a composite intervening layer comprising an extremely thin sub composed of a resin formed by the condensation of formaldehyde or polymers of formaldehyde with ethyl paratoluene sulphamid adhesively joined to the support, a cellulose derivative sub adhesively joined to the resin sub and a gel sub adhesively joined to the cellulose derivative sub and to the sensitive colloid layer, said intervening layer rendering the flexibility characteristics of the film as a whole independent of the degree of adhesion existing between the photographically sensitive layerand the subbed support.

4.A photographic film of satisfactory fiexibility and free from brittleness, comprising a cellulose organic acid ester support and a photographically sensitive colloid layer adhesively joined to the support by a composite intervening layer comprising an extremely thin sub composed of a resin formed, by the condensation of formaldehyde or polymers of formaldehyde with a member of the groupconsisting of the aryl sulphamids and the alkyl N-substituted aryl sulphamids adhesively joined to thesupport, a cellulose derivative sub adhesively'joined to the resin sub and a gel sub adhesively joined to the cellulose derivative sub and to the sensitive colan alkyl N-substituted aryl sulphamid, adhesively joined to the support, a cellulose derivative 7 sub adhesively joined to the resin sub and a gelsub adhesively joined to the cellulose' derivative sub and to the sensitive colloid layer, said intervening layer rendering the flexibility characteristics of the film as a whole independent of thedegree of adhesion existing between the photographically sensitive layer and the subbed support. t

6. A photographic film' of satisfactory flexibility and free from brittleness, comprising a celluloseorganic acid estersupport and a photographically sensitive colloid layer adhesively joined tothe support by a composite intervening bility and free from brittleness comprising a' cellulose acetate support and a photographically sensitive colloid layer adhesively joined to the support by a composite intervening layer comprising an extremely thin sub composed of a resin formed by the condensation of. formaldehyde or polymers of formaldehyde with a member of the group consisting of the aryl sulphamids and the alkyl N-substituted aryl sulphamids adhesively joined to the support, a cellulose nitrate sub adhesively joined to the resin sub and a gel sub adhesively joined to the cellulose derivative sub and to the sensitive colloid layer, said intervening layer rendering the flexibility characteristics of the film as a whole independent of the degree of adhesion existing between the photographically sensitive layer and the subbed support. I

8. A photographic film of satisfactory flexibility and free from brittleness comprising a cellulose acetate support and a photographically sensitive colloid layer adhesively joined to the support by a composite intervening layer comprising an extremely thin sub composed of a resin formed by the condensation of formaldehyde or polymers of formaldehyde with an alkyl N-substituted aryl sulphamid, adhesively joined to the support, a cellulose nitrate sub adhesively joined to the resin sub and a gel sub adhesively joined to the cellulose nitrate sub and to the sensitive colloid layer, said intervening layer rendering the flexibility characteristics of the film as awhole independent of the degree of adhesion existing between the photographically sensitive layer and the subbed support.

9. A photographic film of satisfactory flexibility and free from brittleness comprising a cellulose acetate support and a photographically sensitive colloid layer adhesively joined to the support by a composite intervening layer comprising an extremely thin sub composed of the product of condensation of formaldehyde with ethyl paratoluene sulphamid adhesively joined to the support, a cellulose nitrate sub adhesively joined to the resin sub and. a gel sub adhesively joined to the cellulose nitrate sub and to the sensitive colloid layer, said intervening layer rendering the flexibility characteristics of the film as a whole independent of the degree of adhesion existing between the photographically sensitive layer and the subbed sup 10. A photographic film of satisfactoryflexibility and free from brittleness, comprising a cellulose organic acid ester support and a photographically sensitive colloid layer adhesively joined to the support by a composite intervening layer comprising an extremely thin sub composed of a resin formed by the condensation of formaldehyde or polymers of formaldehyde with a member of the group consisting of the aryl sulphamids and the alkyl N-substituted aryl sulphamids adhesively joined to'the support and a gel sub adhesively joined to the resin sub and to the sensitive colloid layer, said intervening layer rendering the flexibility characteristics of the film as a whole independent of the degree ,--of

adhesion existing between the photographically sensitive layer and the subbed support.

11. A photographic film of satisfactory flexibility and free from brittleness, comprising a cellulose-organic acid ester support and a photographically sensitive colloid layer adhesively joined to the support by a composite intervening layer comprising an extremely thin sub composed of a resin formed by the condensation of formaldehyde or polymers of formaldehyde with an alkyl N-substituted aryl sulphamid adhesively joined to the support and a gel sub adhesively joined to the resin sub and to the sensitive colloid layer, said intervening layer rendering the flexibility characteristics of the film as a whole independent of the degree of adhesion existing between the photographically sensitive layer and the subbed support.

12. A photographic film of satisfactory flexibility and free from brittleness comprising a cellulose organic acid ester support and a photographically sensitive colloid layer adhesively joined to the support by a mixed gelatin-resin sub, the resin component of which is composed of the product of condensation of formaldehyde or polymers of formaldehyde with a member of the group consisting of the aryl sulphamids and the alkyl N-substituted aryl sulphamids.

13. A photographic film of satisfactory flexibility and free from brittleness comprising a cellulose organic acid ester support and a photographically sensitive colloid layer adhesively joined to the support by a mixed gelatin-resin sub, the resin component of which is composed of the product of condensation of formaldehyde or polymers of formaldehyde with an alkyl N-substituted aryl sulphamid.

14. A photographic film of satisfactory flexibility and free from brittleness comprising a cellulose organic acid ester support and a photographically sensitive colloid layer adhesively joined to the support by a mixed gelatin-resin sub, the resin component of which is composed of the product of condensation of formaldehyde with ethyl paratoluene sulphamid.

15. A flexible photographic film comprising a cellulose organic derivative support layer, which layer, if uncoated, would be flexible under dry conditions, a photographic colloid layer carried by the support and having the characteristic of becoming brittle in conditions under which the support remains flexible, and a sub layer between the photographic layer and the support layer and adjacent the support layer, all the said layers being strongly adherent one to another, thesub layer comprising a formaldehyde-aryl sulphame ide resin and rendering the fllm permanently highly flexible.

16. A flexible photographic. film comprising a cellulose organic derivative support layer, which layer, if uncoated, would be flexible under dry conditions, a photographic colloid layer carried by the support and having the characteristic of becoming brittle in conditions under which the support remains flexible, and a sub layer between the photographic layer and the support layer and adjacent the support layer, all the said layers being strongly adherent one to another, the sub layer co'mprising'the product of condensatiQll Of ethyl paratoluene sulphamide with formsensitive colloid layer adhesively joined to the support by a composite intervening layer comprising a thin formaldehyde-aw sulphamide resin sub adhesively joined to the support and a gel sub adhesively joined to the resin sub and to the sensitive colloid layer, said intervening layer rendering the flexibility characteristics of the film as a whole independent of the degree of adhesion existing between the photographically sensitive layer and the subbed support.

18. A photographic film of high flexibility and free from brittleness, comprising a cellulose organic acid ester support and a photographically sensitive colloid layer adhesively joined to the support by a composite intervening layer comprising a thin resin sub composed of the product of condensation of ethyl paratoluene sulphamide with formaldehyde and adhesively joined to the support and a gel sub adhesively joined to the resin sub and to the sensitive colloid layer, said intervening layer rendering the flexibility characteristics of the film as a whole independent of the degree of adhesion existing between the photographically sensitive layer and the subbed support.

GALE F. NADEAU.