US1951043A - Color photography - Google Patents

Description

March 13, ,1934. E. AA. WEAVER coLoR- PHOTOGRAEHY Filed Jan. 31, i930' Duns/01h..

S7/mrt l ,gym Mmm/v Ins' Wibrfeys Patented Mnl'. 13, 1934` PATENT OFFICE 1,951,043 coma Pno'r'ooasrnr Eastman A. Weaver, Winchester, Mass., assignor,

meane assignments, to Technicolor, .Inc.,

New York, N. Y., a corporation of Delaware Application January 31, 1930, Serial No. 425,013

This invention relates to composite photographic fllm comprising a plurality of separable iilms, and is particularly applicable to motion picture nlm provided with a plurality of emulsions adapted to record superposed images for use in producing colored pictures.

One of the objects of this invention is to provide a composite nlm comprising a pair of iilms with their emulsion sides placed face to face and Joined by adhesive' which does not itself cause any appreciable dispersion of light, butv which serves to exclude air from between the emulsions and thus prevents the refraction caused by presence of air between adjacent separately-supported emulsions.

Another object is to provide a composite film of this kind which may readily be separated into its constituent films by rupture of the adhesive without damage to the emulsions, and preferably without the necessityfor treatment of the adhesive preparatory to such separation.

' separation.

A further object is to provide composite rllms of 'this kind in which the adhesive may be readily removed upon separation of the iilm and to provide improved ways of removing the adhesive.

My invention includes also an improved art of making photographic negatives 4.and has for an object to. provide a way of adhesively joining two or more elements of a composite film for perforation, winding. exposure, or storage, whereby the lm may easily be separated for develop-l ment` without the necessity of treating the nlm with chemicals which are injurious to the celluloid supports of the film, or of prolonged soaking .of thecomposite iilm with waterpreparatory to Other objects of my invention will be apparent from the following explanation and from the accompanying drawing which illustrates, diagrammatically and by way of example, two-photographie illms made according to my invention.

Fig. l'is a. side view of a composite'photographic nlm produced with three emulsions; --and Fig. 2 is a similar view of a compositephotographic film provided withtwo emulsions.

The composite photographic illm of li'ig. 1

comprises two supports 11 and 12 ziftransparent, flexible, relatively strong material, such as celluloid, which serve to carry light sensitive emulsions 13, 14l and 16, emulsion 13 being firmly aillxed to.suppo:'t 11, and emulsions 14 and 16 being iirmly afilxed `to support 12.

These emulsions differ in sensitiveness to certain colors, and a preferable arrangement is to utilize an emulsion 16 which is relatively insensitive to green and red wave lengths and preferably chiefly sensitive to blue and violet wave lengths, an emulsionA 14 relatively insensitive to red wavelengths and preferably chiefly sensitive to green wave lengths, and an emulsion 13 sensitive to red wave lengths. Thecelluloicl support 12 and its two emulsions 14 and 16 constitute one separable film, while the celluloid support l1 and its attached emulsion 13 .constitute another .separable film. These two separable lms are united by adhesive 15 to hold them together during simultaneous exposure oftheir emulsions to light. In Ithe drawing the arrow shows the direction of the light. An image will be recorded by the blueA and violet components of the 70 light in emulsion 16, an image will be formed by 4the green components of the light in emulsion 14,

-wave lengths may be prevented from aifecting the red record emulsion 13 byproviding a red color filter incorporated in the entrant side of emulsion 13, in the emergent side of emulsion 14, or in both.

Such color illters are not always indispensible. however, since by utilizing emulsions which are strongly absorptive of predetermined spectral ranges of light, (usually those which form an n image therein) the emulsions themselves may be.` caused to screen from the underlying emulsions these predetermined spectral ranges of light.

While the above described arrangement of emulsions is deemed desirabieone'wof the lthree emulsions may be dispensed with.` Such a construction is illustrated in Fig. 2 of the drawing, in which emulsion 16 is omitted, and the emulsion 14 attached directly to" the celluloid support 12. In of this form of composite nlm, images lol made up respectively ofthe'A red and green components areobtained, and the blue violet image 5s either omitted or, if desired, may be formed separately on another nlm.

The surfaces of photographic emulsions are 106 sion sidestogether, cause refraction of the light` passing from one emulsion to the other. In unit- 110 ing the two illms which comprise my composite nlm I prefer to utilize an adhesive 15, preferably of similar refractive index to the emuls'ons, which serves to lill up the minute indentations of the surfaces of the emulsions and thus minimize the refraction, but which does not substantially separate the two adjacent emulsions nor add substant'ally to the thickness of the composite film. By'the use of an adhesive of this character, the

diifusion of the light passing throughthe emul- -'application to the illms will remain in a soft,

easily ruptured condition.

I have found that the sticking together of two films with their emulsion sides face to face is facilitated if the adhesive contains an appreciable amount 'of water. It seems probable that the water contaned in the adhesive serves to wet the surfaces of the adjacent emulsions and brings into play the adhesive properties of the -gelatine itself.

If emulsions are united by being rolled forcibly into contact afterapplication of pure water, they are likely to unite fully and permanently. I therefore prov=de with the water a substance preferably non-adhesive or only slightly adhesive by itself for preventing such complete and permanent union of the emulsions and reducing the adhesion to a mild and temporary degree adeouate to-hold the lms together during perforav tion, rewinding, storage, exposure, etc., but insunlcient to hinder unduly their later separation when desired. I prefer to employ a'substance which is transparent, in thin layers,fwhich is adapted to retain water and is miscible there-- with and which is non-volatile and non-solidifyingv or slowly solidifying, and have "found that glycerine is suitable for this use. One example of a suitable composition of the'adhesive com- `Drses40 parts of water'and 60 parts of glycerine.

Further to reduce the relative water-content of the adhesive and .regulate its adhesive power, a

lsmall amount of a substance having in itself adhesive properties, such for example as glucose may be added. Such adhesive mixture or solution is capable of remaining in a vscous or fluid condition. The adhssive since viscous .or uid is naturally weaker than the emulsions and supports of the lms, and the composite lm'thustemporarily joined may easily be separated withouty injury to the emulsions and without preliminary treatment, such for example as soaking.A Vacuum probably plays a part in such adhesion, 'as gelatine absorbswater with such avidity as to produce actual suction if the supply is small, as it should be to avoid swelling. y

In prepar'ng composite lm forI motion picture use, the separate supports 11 and 12 each coated with their respective'emulsions may after the application ofthe adhesveto'one of 4the emulsions be brought together with their emulsion sides in contact, pressed tightly together, preferably by, rolls, to insure good contactl and reduce the amount'of adhesive between the emulsions, and if necessary wiped free from surplus adhesive. These operations may be performed rapidly, successively and continuously, and should be performed in darkness or in such degree of illumination as will not affect the sensitive emulsions. When ready for vdevelopment the composite lm may be separated by being pulled apart through rupture of the adhesive, and after separation adhesive remaining on the emulsions may be washed or squeegeed off. The separated films may be developed and vused in any desired manner in the production of-colored pictures. The

through both of these'rimages, the more intense image then removed, and a second print taken through the remaining "image after rendering the latter more intense, inthe manner described and claimed in Patent No. 1,808,584 to Leonard T.

yTroland for Color photography, of May 7, 1931.

Instead of two saparate emulsions, these two images may beformed'in -a single emulsion which has been supercially-color-sensitized.

The placing of the. emulsions 13 and 14 face to face with -no substantial separating body or diffusion-producinglayer or airspace therebetween permits the vlight from the object photographed to form sharp images in both of these emulsions. The adhesion of. the two lms during handlingand exposure eliminates the chance of marking of the emulsions which may result from static, or frictional electrical discharges caused by running twovemulsions together and separating them at relatively high speeds. In addition the sensitive emulsions arevprotected from accidental scratching or abrasion.

I may obtain some of the above described advantages andcertainf other advantages by employing an adhesive which does not necessarily contain water but' which may be applied in such `a. manner asto rlll'thefminute surface'indentations without substantiallyV separating the adjacent emulsions, whichmay easily be ruptured in separating the lms; and after separation may be removed mechanically.

Examples of Vsuch'an adhesive are rubber and transparent cements containing a gum, such as rubber, I prefer to apply such an adhesive in two stages, by first applying a preliminary coat of a thin solution of the adhesive to the emulsion surfaces of the twojlms and then, after drying of lthe originally Huid-adhesive toy form a tacky coating-and'just as the lms areabout to pass between the uniting rollers, applying a solvent for the adhesive, with or without some of the adhesive agent in solution, preferably only over the picture areav of the lms. This method of applying the adhesive insures that the edges of the films will be held firmly together, and permits the exclusion of air from' between the picture areas. i

After exposure, the composite film may' be pulled apart through rupture of-the adhesive, and the adhesive removed, 'if desired,` by passing the emulsion side of theseparated lm and adhering rubber adhesive into andout of lrolling cony tact with a surface for which the adhesive has a greater affinity than :for the emulsion, for example, the surface of a rotary member of tacky rubber. The adhesive on the nlm having more afilnityfor the tacky rubber surface clings to this in passing, and is thus cleanly detached without injury to the emulsion.

Suitable solvents may if desired be employed for removing the adhesive, but I prefer the abovedescribed method of removal since it obviatesany diihculty attendant upon Vthe remaining of sol'- vent with traces of adhesive upon the surface of the emulsion.

From the foregoing itwill be evident that in one aspect a characteristic feature of the invention consists in that the adhesive has less interna] strength than the emulsions have, so that there is no danger of rupturlng the emulsions in the peeling process, and thereafter the adhive may be removed as aforesaid :without injury to the emulsions.

I claim:

l. Art of 'making photographic negative records which comprises joining two photographic lms with emulsions face to face by means of a weak adhesive which fills the surface indentations of the emulsions without substantially separating the emulsions-exposing the combined iilm, separating the two nlms and removing the adhesive from the film. y

2.. Art of making photographic negative records which comprises joining two Vphotographic films with emulsions face to face by means of a weak water miscible adhesive which nils the surface indentations of the emulsions without substantially. separating the emulsions,- exposing the combined nlm, ,separating the two films and removing the adhesive from the nlm.

- 3. A composite film adapted foruse in color photography comprising a .pair of films each coated with an emulsion, said iilms being superposed with their emulsions face to face, the composits lm being provided between the adjacent emulsions with an easily separated adhesive which fills the minute surface indentations of the adjacent emulsions without substantially separating the emulsions whereby refraction of light passing from one emulsion to the other is 'minimized.

4. A composite nlm adapted for use in color photography comprising a pair of tllms each coated with an emulsion, said filmsbeing superposed with their emulsions faceqto face, the composite `111m being provided between the adjacent emulsions with water soluble easily ruptured adhesive which lls the minute surface indentations of the adjacent emulsions without substantially separating the emulsions, whereby refraction of light passing from one emulsion to the other is minimized. Y

5. A composite film adapted for use in color photography comprising a pair of lms each coated with an emulsion, said films being superposed with emulsions face to face and the composite film being provided between the adjacent emulsions with easily ruptured adhesive offering less resistance to splitting of thecomposite iilms than the other elements thereof, whereby the superposed films may be pulled apart by rupt e of said adhesive without injury vto the emulsions, said adhesive being adapted to be removed from the emulsions mechanically without injury to the,

emulsions.A Y

6'. Acomposite nlm adapted for in color photography comprising a pair of films .each coated with an emulsion said films being super-d posed with their emulsions face to face, the composite nlm being provided between the adjacent emulsionsowith adhesive including water and glycerine which lls the minute surface indentations of the adjacent emulsions without substantially separating the emulsions, whereby refraction of light passing from one emulsion to the other '1. A composite iilm adapted for use in color photography comprising a pair of films each coated with an emulsion. said films being superposed with their emulsions face to face, the composite film being provided between the adjacent emulsions with easily ruptured adhesive including a gum which nils thef minute surface indentations of the adjacent emulsions without substantially separating the emulsions whereby refraction of light passing from one emulsion to the other is minimized. Y

8. A composite lm adapted for use in color photography comprising a pair of films each coated with an emulsion, said films being superposed with their'emulsions face to face, the composite nlm being provided between the adjacent emulsions with easily separated adhesive including rubber which4 fills the minute surface indentations of the adjacent emulsions without substantially separating the emulsions whereby refraction of light passing from one emulsion to the other is minimized.

9. A composite nlm adapted for 4use in color photography comprising a pair of films each oated with emulsion, said films being superposed with their emulsions face to face, the composite lm being provided between adjacent emulsions with adhesive including water and glycerne. 1n. A composite iilm adapted for-use in color photography comprising pair of films each coated with an emulsion, said films being superposed with their emulsions face to face. the composite nlm provided between adjacent emulsions with adhesiveincluding rubber and offering less resistance .to rupture than the other elements of the composite nlm. l

11. A composite .nlm adapted for use in color photography comprising a pair of films each coated with an emulsion, said lms being superposed with emulsion face to face and the composite iilm being provided between the adjacent emulsions with normally soft easily ruptured adhesve offering less resistance tosplitting ofthe composite film than the other elements thereof, whereby the superposed iilms may be pulled apart by nipture of said adhesive without injury to the emulsions.

12. A composite film adapted for use in color photography comprising a. pair of lms each coated with. an emulsion, said lms being superposed with emulsions face to face and the composite lm being provided between the adjacent emulsions with normally soft easily ruptured adhesive offering less resistance to splitting of the composite films than. the other elements thereof, whereby the superposed films may-be pulled apart by rupture of said adhesive without injury to"the emulsions, said adhesive being soluble in water, wherebyupon separation of the nlm said adhesive may be removed from the emulsion by water.

13.. Art of removing an adhesive from the emulsion face of a-photographic film without injury to theY emulsion which comprises moving the film into and out of contact with a tacky rubber surface for which the adhesive has a greater ailinity than :for the emulsion, whereby the adhesive clings to said surface and is detached from the emulsion.

14. Art of removing an adhesive containing a gum from the emulsion face of a photographic lm without injury to the emulsion, which comprises moving the film into and out of contact with a surface substantially immovable relative to said lm and for which the adhesive has a greater anity than for the emulsion, whereby the adhesive clings to said surface and is detached from the emulsion.

15. Art of making photographic negative records which comprises joining two photographic lms with emulsions face to face by means of an adhesive which lls the surface indentations of

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