US1183698A - Cinematograph-film. - Google Patents

Description

J. E. THORNTON.

CINEMATOGRAPH FILM.

APPLICATION FILED 1uLY13hx914.

lntvnted May 16, 1916.

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INVENTUR. 7/2 07 l'b WITNESSES.

UNITED STATES PATENT oEEIoE.

JOHN EDWARD THORNTON, OF WEST HAMPSTEAD, LONDON, ENGLAND, ASSIGNOR TO JOHN O'WDEN OBRIEN, OF MANCHESTER, ENGLAND.

CINEMAT'OGBAlPH-FILM.

Specification of Letters Patent.

Patented May 16, 1916.

Application filed July 13, 1914. Serial No. 850,805.

To all whom it may concern:

Be it known that I, JOHN EDWARD THORN- TON, a British subject, residing at West Hampstead, London, England, have invented certain new and useful Improvements in Cinematograph-Films, of which the following isa specification.

his invention provides a means of producing transparent film tapes of printed cinematograph pictures in unlimited length at a much cheaper price than can be produced by the methods now in common everyday use.

Cinematograph picture films are now gen- 4 erally made by taking a transparent, waterproof, and comparatively inextensible material, such as celluloid, cellulose nitrate, or cellulose acetate, of about 5/1000 inch thick, for a base and coating thereon a layer of sensitive gelatino-bromid emulsion, which when dry, is about 1/1000 inch extra thickness. This film is perforated near its two edges, and then printed, developed, fixed, Washed, and dried by the usual well-known methods. During these operations, it shrinks longitudinally somewhat. The cellulose materials comprising the base are very expensive, and constitute the main cost of the complete sensitized film. But it is necessary to use these cellulose materials because they are the only satisfactory transparent medium at present known that are sufliciently waterproof to stand the various developing, fixing, and washing operations, and at the same time capable of properly supporting the delicate gelatino-bromid emulsion during treatment therein, without either unduly stretching, getting out of shape or crinkling up during drying, or falling to pieces while wet. And moreover, they are the only known transparent waterproof materials which are pure enough to have no deleterious action upon the delicate, highly sensitive emulsion. Celluloid and other nitrate forms of cellulose are expensive enough, and have the disadvanta e of great flammability; while the acetate orms of cellulose, though less inflammable, are still more expensive.

In this invention I use for the base of the finished cinematograph film an old wellknown photographic material, but in an entirely new way. I substitute for the expensive but inexpensive waterproof cellulose base, one which is non-waterproof, and therefore is expansible, but which is very cheap (as compared with acetate or nitrate cellulose) yet is entirely fire-proof, its degree of non-inflammability, under the conditions that cinematographic films are used, being far in advance of the so-called non-inflamable cellulose acetate films. This material is a non-waterproof colloid or colloids, of which gelatin may be taken as a type to illustrate the principle. I do not, however, confine myself entirely to gelatin, for other colloids, or similar substances may be used, or even mixtures of two or more, including such as gelatin, glue, Iceland moss, agaragar, alginatos chrondin, albumin and the like. None of these colloids is any use as a base for cinematographic films when re quired to be sensitized, developed, washed and dried in the usual way. But using them in the way hereinafter described they are eminently satisfactory.

In describing the methods of carrying the invention into practice I will use the term gelatin as covering any one or any combination of the aforesaid absorbent colloids or substances, and especially as gelatin 'alone is a very suitable colloid on account of its high degree of purity, transparency and strength.

The use of gelatin and some other colloids as a support for sensitive emulsion is very old, it having been proposed over and over again as a suitable support, and in fact such sensitized films have been extensively offered for saleto photographers, for ordinary pictures, only to be subsequently withdrawn or abandoned asuncommercial. In ad dition to that it has been proposed to use of film could be dried flat by resorting to many troublesome and lengthy operations, with the great lengths of narrow film tape required in cinematography the drying presented an insurmountable commercial difficulty, and the alteration in size by expansion and shrinkage presented a further difficulty that has never yet been commercially overcome. The foregoing description of the art to-day will therefore better illustrate the important further step of improvement accomplished by this invention.

The present invention is capable of being carried out by the aid of apparatus of different kinds. In the accompanying drawing, the apparatus is shown diagrammatically, wherein Figure 1 is a perspective view, and Fig. 2 is a corresponding longitudinal section through the component parts of the film and the means employed for uniting the same.

In carrying the invention into practice, I adopt the simple principle of keeping the sensitized film B and its transparent support C separate durin manufacture, bringing them together to %0rm one complete whole only after the picture has been completed that is, printed, developed, fixed, washed and dried.

The two component parts of the finished film picture-that is to say, the transparent non-waterproof and absorbent colloid base, and the non-waterproof gelatin-br omid (or other form of) sensitive films-may be formed, coated, or cast upon non-extensible surfaces, or temporary supports upon which they remain until dry. The thick gelatin base may remain upon its temporary support until the two parts of the film are united and the support not removed until they are dry, when manufacturing the gelatin base in narrow widths, or when manufacturing it in wide widths it is removed from its support when dry and slit up into strips of narrow width to be subsequently affixed to the printed film. The sensitized film B remains upon its temporary support A until-it has been printed, developed, fixed I and washed and until the gelatin base or backing C has been attached and the combined film dried. The said non-extensible surfaces or temporary supports are preferably strips of polished metal A, though polished waterproof paper, celluloid, or other suitable materials may be used.

The manufacturing advantages of this system are.(1) The layer of sensitized film is so thin that it is very easily and readily developed, fixed, washed and dried. (2) None of the chemicals or water used in these operations come into contact with the base; therefore it absorbs nothing and there is nothing to be washed out (as has been the case in all previous films where the sensitive emulsion and gelatin support are combined by the film manufacturer for subsequent use by the photographer.) (3) A cheap gelatin support can beemployed because it is not treated with Water, and the sensitive gelatin emulsion cannot expand longitudinally or laterally during any of the operations, the only expansion which can take place consisting of-swelling in a vertical di rection. This is due to the fact that it is held in face-contact with the non-extensible support A during all operations.

After the sensitive film B has been converted into a series of finished pictures, the support or backing of transparent colloid C is applied thereto. The picture may be wet and the backing dry, or vice versa, one or other being first coated with a substratum of the usual adhesive character as well known to those versed in the art, and then dried. It is suflicient to slightly moisten one or the other, or both surfaces, such as by passing through a steam box, or under a fine spray of water, and then squeeze them into contact by rolling pressure, and finally allowing them to dry spontaneously. Or, if preferred, they may be passed together through a water trough, and squeezed into contact by rolls D, D, while under the surface of water, to prevent all possibility of air bubbles being inclosed between the united surfaces.

The coating or casting of the two films may be done by any of the well-known methods; and drying is done in drying chambers supplied with filtered air at the right temperature in sufficient volume to dry the 'united films at the right speed. These'are all matters well understood by those skilled in the art .of film manufacture upon a large scale, and form no material partof this invention.

The picture film may extend the full width of the base film (when both are trimmed to correct finished width), but I find it more convenient to form the picture film of a narrow width, so as to just fill up the space between the two lines of perforations, instead of extending over and covering them.

The base film may be hardened by any of the substances generally used for that purpose, such as chrome alum, formalin, or the like, either by incorporating them with the gelatin base before it is cast, or by passing it through a solution thereof after casting and before drying; or even after drying, which involves re-drying but possesses certain advantages.

As already stated, mixtures of different colloids may be used instead of or in addition to gelatin, in order to secure strength, cheapness or other advantages. And suitable substances for securing flexibility may also be added, such as sugar, glycerin, or

molasses; also any salts that will render it more fire resisting such as borates, silicates or similar substances. Also in order to secure increased strength with decreased absorption, and yet still retain the main features of a non-waterproof colloid base, the gelatin may have incorporated therewith a small proportion of the fibrous soluble celluloseeither nitrate or acetate (but preferably acetate)which can be easily incorporated in such manner as to not materially affect the distinguishing qualities or transparency of the colloid base. The methods of eflectin such mixtures are well known.

Althoug I have described this invention as being carried out with gelatin-bromid emulsion as the sensitive medium (because that is the type in almost universal use for cinematograph films to-day), it will be obvious that it may be used in conjunction with any other desired printing medium, such as the so-called gaslight emulsions, containing silver chlorid, bichromated gelatin processes, such as the carbon, or pigment or powder processes; mordanted dye processes; or any other that may be considered suitable for use for cinematographic pictures.

After the two films have become united and absolutely dry they are stripped, as one complete film E, from the polished temporary support, and may then be trimmed if necessary, as well as perforated or otherwise finished; and may also be varnished with waterproof varnish (of celluloid, cellulose acetate, or other material in suitable solvents) to increase durability.

The manufacturing process and constructions described may be applied to the production of films in one color, or to films in several colors (known as natural color films) as described in several other patent applications of mine dealing with various types of color films.

What I claim as my invention and desire to protect by Letters Patent is 1. The process of manufacturing printed cinematograph picture films which consists in preparing a transparent strip of non-sensitized gelatin or other similar colloid or substance (either with or without an inextensible temporary support) and a transparent strip of sensitized emulsion mounted on an inextensible temporary support (transparent or opaque) printing, developing, fixing and washing the sensitive film while mounted on its inextensible support, subsequently applying to the printed. film the gelatin or other transparent absorbent strip to form a permanent base and finally stripping the completed film when dry from the temporary support substantially as described 2. A process for producing printed cinematograph picture films consisting in attaching a continuous thick non-waterproof colloid base to an infinitesimally thin printed image on an indestructible support after the latter has been developed, fixed and washed, and while still wet drying the two in unison while still on the temporary support and stripping the combined film from the support when dry substantiallv as described.

3. As a new article of manufacture, a noninflammable transparent cinematograph film for projection purposes, comprising a thick base or film strip composed of a colloid or mixture of colloids of non-waterproof character, such as gelatin, glue, agar-agar, albumin, or the like water-absorbing mate-, rials, having a series of perforations for moving it through a projector or lantern, and bearing attached or cemented to its surface another layer of exceeding thinness, comprising a series of photographically produced images that have passed through the usual operations of printing, developing, and washing while mounted upon another ternporary support, from which it is afterward transferred, while in a damp or tacky condition, to the dry film strip of colloid during the process of manufacture, the two together fonning the finished'picture film.

4. As a new article of manufacture, a noninflammable strip of continuous transparent cinematograph film for projection purposes, which is non-sensitized and is composed of non-waterproof colloids, and is therefore quite unsuitable for subjecting to the usual developing or water baths, and bearing on one or both faces a series of pictures firmly cemented thereto, the said pictures being photographically produced .upon a separate exceedingly thin film or Wafer of sensitized material Which is printed, developed, and washed while attached to a temporary support, from which it is afterward transferred and cemented to the aforesaid thick, nonwaterproof, non-inflammable, permanent support which forms the base, the two together forming the finished picture film.

5. A printed cinematograph picturefilm comprising a thin printed and finished strip of emulsion with pictures printed thereon,

and a continuous thick base of a strip of I cheap absorbent non-flammable colloid which has not received any developing, fixing, or washing treatment.

6. A printed cinematograph picture film built up of a printed and finished strip of emulsion which has been printed, developed, fixed and Washed, and a continuous basestrip of gelatin not treated with developing, fixing and washing solutions.

7. A printed cinematograph picture film built up of a printed strip of sensitized gelatin which has first been printed, developed, fixed and washed upon an inextensible support, and a continuous base of a cheap absorbent non-flammable colloid substance to which the printed strip has been transferred and caused to adhere after being finished, the compound film being subsequently furnished with perforations for moving it through a projecting apparatus or lantern, substantially as described.

8. A printed cinematograph picture film built up of two layers after printing, one being a finished printed picture strip, and the other a non-treated, absorbent, non-fiam mable gelatin colloid strip caused to adhere thereto.

In testimony whereof I have hereunto set my hand in presence of two subscribing witnesses.

JOHN EDWARD THORNTON.

Witnesses:

CHARLES E. TAYLOR, DORA H. GIBSON.

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