US1758184A - Manufacture of multicolor cinematograph films - Google Patents

Description

MANUFACTURE OF' MULTICOLOR CINEMATOGRAPH FILMS May 13, 1930.

Filed Nov. 2, 1926 2 Sheets-Sheet l Figi.

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May 13, 1930. J. E. THORNTON 1,758,184

MANUFACTURE OF MULTICOLOR CINEMATOGRAPH FILMS "Y: 2 sheets-sheet 2 Filed Nov. 2, 1926 oyagwu A fio e Patented May 13, 1930 UNITED STATES PATENT OFFICE JOHN EDWARD THORNTON, OF WEST HAMPSTEAD, LONDON, ENGLAND,

l JOHN OWDEN OBRIEN, OF

MANCHESTER, ENGLAND MANUFACTURE OF MULTICOLOR- CINEMATOGRAPH FILMS Application tiled November 2, 1926, Serial No. 145,897, and in Great Britain December 5, 1925.`

This invention provides an improved form or multi-layer multi-color cinematograph film-positive, together with special film-material for its production, and process of manufacturing the multi-color' prints or positives upon such material.

The film-material, according to the inver),- tion, from which the multi-color cinematograph film-positive is built up comprises a sensitized layer of gelatine or other` suitable non-waterproof colloid, divided into longitudinal strips of different colors, of a width approximately equal to the multiple of the numlr of colors and of a thickness in the inverse ratio of the number of colors, the sensitized layer being manufactured upon a temporary backing or temporary Support of paper, celluloid or other suitable material which is so prepared that the backing can be readily removed from the colloid film at a later stage.

he present invention is distinguished from all. other cinematograph multi-color films in that the finished film-print is composed of layers of colloid without any interleaved layers of Celluloid or similar waterproof material. The term colloid means gelatine or any other suitable substitute of like nature, and such materialis non-waterproof.v Therefore the multi-layer film-print produced by this invention is not waterproof until it is finally rendered' so by the application of celluloid or other waterproof coatings to its outer surfaces as a last stage of its manufacture.

T he stripis of multi-width the several colored strips of colloid being arranged side by side in parallel rows upon a multi-width tempora ry support Which-forms part of the filmmaterial during the earlier stages ofthe process.

The invention is illustrated by the accompanying drawings which with the following description show and describe it as applied to the production of four-color pictures.

Fig. 1 is a ltransverse section (enlarged transversely) of the film material.

Fig. 2 is a plan of same.

Fig. 3 is a transverse section (enlarged transversely) of the finished film:-

-throughout the description.

Fig. 4 is a perspective view showing the finished film.

Fig. 5 is a diagrammatic view illustrating dyelng troughs for coloring the film.

Fig. 6 is a plan view showing one arrangement of the component pictures on the multiwidth strip.

Fig. 7 is a plan view showing another arrangement of the component pictures on the multi-width strip.

Four-color film-material In carrying the invention into practice the first step is to provide a suitable film material, consisting of a layer of sensitized gelatine with a thickness of nearly one fourth that of the finished film, prepared upon a temporary support from which it can be stripped at a subsequent suitable stage.

In one form of the invention this film-body is formed upon a temporary support, suchas paper prepared with a suitable stripping surface that will hold the film-body during the various operations and allow of its removal from the temporary support by pulling off' after such operations are completed.

In another form the film-body is prepared upon a glossy manufacturing support such as Celluloid, from which it is likewise stripped after the operations are completed.

Of the two forms it is preferred to use the one in which the gelatine body is cast or coated on to a prepared paper temporary support which remains attached during the operations, and hereinafter that form is used But it will'be understood that the invention is not restricted to use of the preferred form.

The surface of the paper is first coated with the colloid (preferably gelatine), Which serves the double purpose of forming a holding body for the sensitizing salts and for t-he dyes or other coloring matter, and also as the body of the film itself, or -body of one substance thus performing the two functions which in other films are performed by two layers consisting of two quite different materials, vizz-celluloid and gelatine.

The sensitizer may consist of the usual fioY the one layer salts of silver, combined with the gelatine body by being made up into an emulsion of moderate rapidity (suitable for develop-' ment) in well-known manner, which is then coated on to the temporary support of paper. Or the colloid may be first coated on to the paper support after which the sensitizing salts of silver are applied as a solution which v is absorbed into the colloid, thus producing a sensitized layer of much lower speed (suitable for printing out) Or the colloid may be first coated on to the paper support after which it is rendered sensitive by applying a solution of bichromate salts, thus producing a sensitized layer suitable for the processes ency, though vegetable or mineral colors may be used alternatively. The coloring matter may be incorporated with the colloid before it is spread upon the paper support, but 1 prefer to apply it (where solutions are used) by first drying the colloid and then applying the colored solutions thereto by doctor rollers, see Fig. 5, until the colloid has been completely saturated -with the solution, right through from face to back of the layer, after which the now colored layer is re-dried.

The colloid or sensitized colloid is spread by coating a fluid solution over the Whole surface of a strip of the temporary paper support having a width equal (when a four-color strip is required) to four times the width of the final finished single-Width film, and proportionately for any other number of l colors, with a little added to allow for final trimming to correct width when the layers lare finely superimposed and united together. In practice it is generally convenient to manufacture the film-material in theV forni of a wide web, which is afterwards longitudinally slit and severed toform a number of such four-width (or other multi-width) strips.

The dyes, each of a different color, are applied to the strip by four doctor-rollers which rotate in four doctor-troughs (see Fig. 5) each containing a different color, the rollms being each of such width that they apply four parallel strips of color, separated by a narrow uncolored strip or margin between each so that the lcolors will not spread or run into each other. The film is the'n dried and is ready for use.

4same method is employedv except In some varieties of sensitizing hereinbefore described the colors may be incorporated with the sensitizing solutions and applied at the one operation, if such 'method be de- Sired. Y

The finished f ur-width film-material will now consist of a sensitized gelatine body of quadruple width supported upon its temporary support or backing, the gelatine body comprising four 'differently colored parallel stripes. For four-color pictures the gelatine body is made with a thickness of about .0012 of an inch thick, and for three-color pictures would be proportionately thicker' to produce a finished film-picture of standard thickness. vThe thickness of the paper or other temporary support is not material so long as it is stiff enough to adequately resist the pull of the gelatine body during expansion and contraction. A

The paper itself may be of any description It is not essential to use a high grade photo-l graphic white rag-paper, as the sensitized gelatine body is isolated from the paper by the stripping layer or preparation.' Therefore the paper forming the stripping medium, if desired, consistsof cheap strong brown manila packing-paper, suitably prepared and water-proofed by impregnation with hot wax, aluminum-acetate, stearate, or the like, and then well rolled.

Arrangement of perforations, registration and staggered 'image-components The .four-width film is provided with one registration hold for each component `image at the left side thereof. i

For the present invention different'methods are adopted from those usually employed for perforating, printing\and registering ordinary films.

Single component prinfng.-The four component images of each picture may be 'y arranged side by side across the quadruple width negative film,l and in this case only one picture of the group at a time is exposed, the remaining ones being each exposed separately at successive exposures. Thus the registration pin of the printingmachine in -contact-printing engages one hole in the left side of the film and one hole in the left side of the. negative. In projection-printing the that the film is engaged by one pin in the film-holder and the negative by a similar pin in the negativeholder, thelens being between the two and the two mechanisms positively driven by gearing at the same speed and synchronized.

After the first exposure both the film and negative then move a step forwardand at the second step of the cycle the picture in the second strip is similarly exposed. At the third step of the cycle the picture in the thirdl strip is similarly exposed. Finally, at the fourth step of the cycle the picture inthe fourth or right hand row is exposed. Under this method the four components are exposed separately and successively in staggered formation.

F our component p'rz'ntz'ng.-To increase the speed of' production four component images, all of different picture groups arranged at predetermined distances apart, can be exposed at one time.

Thus for example as shown in Fig. 6 if the first component image A1 on the first strip A is being exposed, the fifth image B"I on the second strip B, the ninth C9 on the third strip C and the thirteenth D13 on the fourth strip D can also be undergoing exposure.

This arrangement normally allows sufficient space between any two images undergoing exposure for lateral shrinkage of' the film, sufficient give or twist being possible in that distance to compensate for lateral shrinkage but such distances may be increased if necessary and to compensate for longitudinal shrinkage a little slack or loop is allowed (in both negative and positive films) to form between each of the images under-going exposure.

The next component images to be exposed will then be the A2, B, C10 and D14 respectively and so on.

By this means the same degree of accuracy of registration is secured as if the one group of four images were superimposed and simultaneously registered upon one pin, and the same speed of printing-out-put is obtained as if they were all components of the same picture.

The four component images of each picture need not however be arranged side by side across the quadruple width negative film but may be arranged in staggered relation thereon, as shown in Fig. 7', that is to say the component image B1 on the second strip B corresponding to picture number 1 is in the same transverse row as the component image A eorresponding to picture 5 on the first strip A, and the component image C1 corresponding to picture number l on the third strip C in the same transverse row as component image A corresponding to picture number f) in the first strip A and component image B1", corresponding with picture No. 5, and in the second strip B: finally image D1 in the further strip D is in the saine transverse row as image A13, strip A, B9 in strip B and C5 in strip C.

lith this arrangement all the component images of each picture can be exposed at the same time since these are no longer situated adjacent areas on the quadruple width The negatives or printing de/ies b v-side, thus forming four parallel series. These may have been produced by any known method, either by photographing direct in the camera or by analysis and reproduction from sets photographed in any suitable Way. Examples of how the originals and reproductions can be formed will be found described in my specifications Serial Nos. 711,251 and (36,603. The terln negative" is herein used in the sense of a printing-cliche, which may be either ofnegative or positive character according to the sensitizing and printing process used and should be of the "full-tone (not broken-tone"`) description. although broken-tone 'cliches can be used (with less eflicient results) if desired.

Painting 271e .sensitive //m Printing is `carried out by exposing the sensitive film beneath the printing-cliche to a source of light, by apparatus of' known type. This part ot' the work calls for no special description other than to say the light used be accommodated to the sensitizing processes used, in general terms electric filament lamps for rapid-film and mercury-vapour lamps for slow-film. Exposure is made either by projection or contact, according to sensitivity of the film. The printing machine must be wide enough to admit the wide strip, and tubulailamps are used with a width sufficient to illuminate and cover four negatiif'es at the same time in order to secure equal illumination for each component.

Develop/ng the film As already stated the developing and other treatment is that required for the particular sensitizing and printing process adopted and the image produced may be either of the relietl or non-relief' type.

The printed film may be developed upon its paper support Without additional support, but it is more convenient to squeeze it into firm adhesive contact with an adhesive belt of metal, celluloid, artificial leather-cloth. linoleum, or the like, the belt preferably being of either continuous or endless form, passing around supported and moved by a series ofl drums carried upon suitable shafting, a good arrangement being that described in 1n British specification No. 28,875 of 1919.. The belt is rendered adhesive by flowing upon it a thin Solution of rubber in benzole, which is then dried and the film attached to the rubbered side by laying thereon and passing both between a pair of squeegee rollers. 0r a solution of gutta-percha may be substituted for the rubber, in which case the film can be adhered to the belt by means of' applied heat and pressure and removed from the belt by the further application of heat..

Supmimposz'ng and uniting t/ze component ylms The process of uniting the separate filmcomponents to form a single film can be carried out by either of two methods. In the first and preferred method the binding agent or cement is of a colloid type, and in the second method it is of a cellulosic type. Each requires applying in a different manner and slightly different film-material, though the principle of building up by use of a binding agent is the same in each case. Each method will now be separately described in detail.

Uniting by colloz'd When the colloid method of uniting is to be used the film-material comprises the gelatine film-body and temporary support already described` Applying the @eww/nt After development, and either after or before drying the printed finished film-body is treated with an adhesive cementing solution, which is preferably applied until the thick gelatine body is completely saturated and penetrated to the back with the solution and will absorb no more.

A convenient adhesive cementing solution is composed as follows Ounces or parte Best quality pale glue 100 Glacial acetic aci 50 Glycerine or golden syrup treacle 10 Ammonium bichromate 1 Vater 100 The glue is soaked in 90 parts of water until soft, then melted by gently heating in a jacketed vessel, and the glycerine or treacle is next added with constant stirring.

The bi'chromate is dissolved in l() parts of warm water and gradually' added to the glue solution with constant stirring. Finally, the acetic acid is added, the whole thoroughly mixed by constant stirring, and then, after filtering, the adhesive cement is ready for use in the manner already described.

Variations of the ingredients named may be made provided they produce similar ef'- fects. For instance, fish glue may be substituted for pale-glue, sulphuric or other suitable acid for acetic, and the proportions of each ingredient of the cern-ent may be adjusted to suit these adhesive-ingredients. The proportions of solids to liquids may also be varied or adjusted to suit the particular grade of gelatine composing the film layers. The proportions given above are an example of a mixture suitable for an average case, but the invention is not restricted thereto.

Having saturated the film body or layer with the adhesive it is allowed to dry, preferably in a drying-room or chamber fed with dust-filtered and warmed air by means of a fan. The glycerine or Syrup contained within the body of the gelatine film will prevent it becoming absolutely dry, although it will become sufficiently dry especially upon the surface, for purposes of handling.

During the saturating and drying processes the film and its temporary support may, jafldesired, remain attached to the adhesive Slittz'ng, assembling and @amanti/ng The next step is to strip the film and its temporary backing from the adhesive developing belt and remove any surplus adhesive that may remain by cleaning the back by passing it over rotating polishing pads suplied with a suitable cleaning solvent.

The quadruple width-film then passes into the slitting-machine, where it is divided into four strips of single-width.

From thence, it passes into the assembling and uniting machine, where the fourstrips are brought into superimposition and the four component images of one picture are accurately registered, by means of registering pins which exactly fit the perforations, the four parts of the same picture all being registered in superimposed order upon the same registering pin, which passes through the four holes of the four films.

The slitting, assembling and uniting machines are all parts of one apparatus, one form of which is described in my British Patent No. 12,229, of 1912.

At the next step of the operation by this machine the four films are squeezed together between heated metal blocks or heated metal rollers, whilst the faces of the films are united owing to the glue (which is kept moist by the glycerine or syrup) becoming slightly melted, so that the parts are literally fused together as one; the process being concluded by the recooling of the film, which may be assisted if necessary by a blast of cold air directed upon the amalgamated films as they emerge from the squeezing blocks or rolls.

This brings the process down to the stage at which a very good physical union of the film surfaces has been effected. But if the cemented film were to be used in that condition the thin films composing it could be readily separated again upon the application of heat, such for example as the heat of a hot lamp of a cinematograph projector.

The next step therefore is to convert this still fusible temporary joint into a non-fusible permanent joint.

iVhere a small proportion of a bichromate salt has been incorporated in the cement, as in the example already given, this condition is brought about by exposing the film to a source of light, for example a mercuryvapour lamp or an arc-lamp, over which the film is passed as it slowly travels in its passage to the winding reel. By this means an insolublizing action is started'. b v which the glue of the cement and the gelatine layers into which it has soaked are all rendered after drying,

f ture still retained in more or less insoluble to any further ap lication of heat, the degree of insolubility eing a continuing and an increasing one, after the action has once been started by light, until the limit of insolubility is reached.

In the above process the film is very slightly colored by the bichromate and this is not detrimental to the picture when being projected. But if the pale vellow tint is objected to it can be. avoided by substituting for the bichromate some hardening salt which does not require the action of light to setup the necessary reaction. An example of such hardening salt is chrome alum. This may be substituted for the bichromate in the formula given, and in about the same amount. No light action is necessary as the glue and gelatine will yboth become more or less hard or insoluble in time, but the hardening process will take far longer, and although the result is good. it is less satisfactory than when' bichromate and light are used.

The united films will now have formed a single film, and owing to the quantity of moisglycerine or treacle remaining) the layers will retain their suppleness and the combined film will possess the necessary flexibility notwithstanding the number of its layers, and its component parts will not become separated by severe and prolonged use. N one of these results would be attained if the films were merely glued together by the application of glue or other cement to their surfaces. In such case the combined film would be stiff' and not easily rollable, and the components would be frequently coming apart.

U m'zfz'ng by cellulose )Vhcn the cellulosic method of uniting is to be used the film-material comprises the gelatine film-body, the temporary support, and a cellulosic, layer which is united to the underside of the gelatine-body (between gelatine and support) during the process of manufacture of the film-material, as already described.

After development, and either 'before or the printed finished film-body is treated with a suitable solution of cellulose which is applied to the face of the printed film. partially penetrates its body, and finally is allowed to dry slowly in order that it may effect a perfect union with the gelatine face during the process of drying and shrinking. The printed finished film may then be stripped from its temporary support When it will then be in the condition of having a cellulose facing firmly attached or shrunk on to both sides or faces.

In this condition the several films are passed into the assembling and uniting machine, where a solvent of the cellulose is applied in minute quantity to both sides of the film, sufficient to just soften, and convert the two cellulose facings into cellulose Cement,

the film (owing to the' care being taken that the amount of solvent applied is insufficient to completely dissolve and wash the cellulose facing ofi' the gelatine film-body.

Then the films are squeezed together by the uniting machine the cemented faces will adhere, and eventually dry, thus producing a single filmstrip of homogeneous character.

The [est steps The compound film has now reached the stage at which it has become a single film of four-color positive pictures. It could be used in this state, but it is preferred as a completing operation to coat the film on both sides with a layer (or preferably a series of extremely thin layers) of cellulose, by passing the film through apparatus which will apply a solution of' Celluloid in amyl-acetate or a solution of' cellulose-acetate in acetylenetetrachloride, (or any other suitable solvent for either form of cellulose) after which the film passes into a dry-room or chamber where the coating may dry slowly. After emerging from the varnishing apparatus and before entering the drying room the film passes between two air-jets which blow any surplus varnish from the perforations and prevent any filling of varnish forming therein.

The final step consists in passing the varnished film through a perforating machine Whi ch adds the series of standard perfolations for traction purposes, the. single hole per picture already existing for registration purposes being used as the feed and guide hole to engage with the feed pin of the machine and also to correctly locate the series of eight traction holes per picture usually adopted as standard, or any other style of traction perforations.

The film is now reeling.

lVhat I claim as my invention and desire to protect by Letters Patent is 1. A multi-layer multi-color film-positive of standard width and thickness comprising a plurality of differently colored partial image containing colloid layers, the thickness of each layer being in inverse ratio to the number of layers, a layer of adhesive between adjacent layers of colloid by Which they are indissolubly cemented together and a layer of cellulose varnish applied over the outer surfaces of film to protect it from the a-t mosphere.

2. The method of producing a multi-Width multi-layer cinematograph colloid film positive comprising coating a temporary reinforcing backing with colored colloid arranged in a plurality of parallel stripes, sensitizing the colloid, printing component images one at a time in a straight line across the multi-Width film, severing the film into a plurality of strips of single-width, removing the paper reinforcement, cementing the complete and is ready for printed colored strips together in accurate register and adding a layer of waterproo Varnish.

3. The method of producing a multi-Width multi-layer cinematograph colloid film positive comprising coating a temporary reinforcing backing with colored colloid arranged in a plurality of parallel stripes, sensitizing the colloid, printing component images one at a time in a straight line across the multiwidth film, preventing expansion and distortion of the colloid body during the development and retaining its correct size and shape, during drying by developing and drying the colloid body Whilst attached to the temporary supporting backing, severing the film into a plurality of strips of single Width, removing the paper reinforcement, cementing the printed colored strips together in accurate register and adding a layer of Waterproof varnish.

In testimony whereof I have hereunto set my hand. v

JOHN EDVARD THORNTON.

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