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Publication numberUS2030163 A
Publication typeGrant
Publication dateFeb 11, 1936
Filing dateMay 28, 1934
Priority dateJun 6, 1933
Publication numberUS 2030163 A, US 2030163A, US-A-2030163, US2030163 A, US2030163A
InventorsThorne Baker Thomas
Original AssigneeDufaycolor Ltd
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Color photography
US 2030163 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

Feb. 11, 1936. T. T. BAKER 'coLoR PHOTOGRAPHY Filed May 28, 1934 E an R6 N T E E E D mm M w :IIV VTOFI 29/%%,M-.MM

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Patented Feb. 11, 1936 UNITED STATES PATENT OFFICE COLOR PHOTOGRAPHY Application May as, 1934, Serial No. 728,031 In Great Britain June 6, 1933 Claims. (01. 95-815) This invention consists in improvements in or relating to color photography. It has already been proposed (for example in United States Patent No. 1,805,361) to produce a multi-color 5 screen on films or plates for use in color photography or color cinematography by a process in which a-series of lines of greasy ink are applied to the film or plate by means of an engraved roller. It is found in practice, however, that such a roller is diificult and expensive to make and particularly so if more than 20 lines and 20 intervening grooves per millimetre are required. The screen produced by the process using an engraved roller consists of regular lines or squares of colored elements, and it is found diflicult to engrave a roller of sufiicient fineness having the lines and grooves or other pattern of non-regular formation. It is, however, desirable that the color screen shall consist of irregularly arranged elements in order that the eye may not easily disoern the elements and in order to minimize interference effects between the color screens when printing. It is among the objects of the present invention to provide a method for producing a color screen having fine elements, and, if desired,

.of non-regular shape or in non-regular formation.

It has already been proposed to use printing surfaces having mercurial ink repelling areas, and it has now been found that such a method is particularly applicable to the production of color screen films or plates.

The present invention provides the process of making a multi-color screen for color photography or cinematography which comprises applying one color, or colored layer, to the surface of a film or other suitable base, applying a pattern of greasy resist to the colored surface by means of a printing surface (e. g., a roller) having mercurial ink repelling areas, bleaching the color from the portions of the colored surface unprctected by the resist, dyeing the bleached portions a second color and removing the resist. Preferably the steps of applying the resist by means of a printing surface having mercurial ink repelling areas, bleaching the color from the portions of the-colored surface unprotected by the resist, dyeing the bleached portions and removing the resist are repeated to form a threeor four-color screen.

When it is desired to produce a screen having the elements in non-regular formation or nonregular shape, the ink repelling areas of the resist applying roller are non-regular in form or arrangement. but are. of course, so proportioned as to provide the desired ratio between the total areas of the several colors in the finished screen. The invention includes a photographic film or plate having a multi-color screen when produced by' the above described method. 5

A description of one method of carrying the invention into elfect in the production of cinematograph films for use in making pictures in naturalcolors will now be described by way of example with reference to the accompanying 10 drawing in which:-

Figures 1 to 6 are diagrams to a very greatly increased scale of the screen in various stages of its preparation,

Figure 7 is a section of the printing roller em- 5 ployed and Figure 8 is a diagrammatic development of a portion of a printing roller used for the first resist applying step. v

A cellulose acetate film is produced in any 20 known way, but, preferably, according to the methods described in British Patent No. 287,635 and United States Patents Nos. 1,811,689 and 1,666,377. The thickness of the film may be about 0.0055 inch, and the film isconveniently coated on a width of about 21 or of about 42 inches. The clean film, from a bobbin, is led through a coating apparatus, preferably of the type described in United States Patent No. 1,929,877. The object isto apply on one side of 30 the film a fine layer of collodion of a definite and uniform thickness, which embodies one of the three primary color dyes for example, the green dye. It is this collodion coating which is to receive the various dyes, and in determining 35 the composition of the collodion and the thickness of the layer the determining factor is that the ultimate colored portions shall give the correct spectrum absorption. Solutions of indus' trial collodions of different nitro-cottons are 40 mixed together in such quantities as to afiord the required viscositythe proportions being varied to suit the temperature, humidity, and similar conditions. The collodion mixture is dyed green with an alcoholic solution of malachite green 45 and of .auramine. The composition of the dye may be, for example, alcohol parts, malachite green 4 parts, auramine 6.7 parts and the composition of the collodion mixture may be, for example, collodion mixture 30 cc. dye solution 2 50 cc. For instance, in practice it has been found convenient to apply this solution in such a thickness that an area of 100 c. long W26 0. wide, takes 22 to 25 cc. Thus, the thickness of the layer is.about..01 millimetre wet, i. e., .0002 to 55 .0005 millimetre when dry. Alternatively the collodion layer may be put on uncolored and thereafter dyed.

The film dyed uniformly green all over is then led through a printing machine by means of which an extremely fine irregular pattern of greasy ink (intended to act subsequently as fatty resists) is printed upon it. The film at this stage is as shown in Figure 1.

' The printing is effected by means of a steel or other roller having extremely fine chromium inking areas I and mercurial ink repelling areas 2 as shown diagrammatically in Figure 8. The roller a section of which is indicated in Figure 7 is produced by the known method of plating a roller with silver as indicated at 3 and then with chromium as at 4 and then coating the plated surface with bi-chromated gelatin, photographically printing onto the gelatin a series of lines (or other figures) and developing the figures with hot water, etching away the chromium from the parts of the roller unprotected by the hardened gelatin and treating such parts with mercury so as to form an ink-repelling amalgam with the underlying silver. It is found that the amalgam is strongly repellant to greasy ink, but that the chromium surface will retain the ink and transfer it to the film. When it is desired to print a resist in any particular pattern, it is only necessary to produce an enlarged model of the pattern and to reduce it photographically on to the bi-chromated gelatin. A roller hearing this pattern may thenbe produced as described.

After an interval of about an hour, to let the ink dry, the film is led in succession (a) over a bath which bleaches and dissolves out the green dye from only the clear spaces, leaving unattacked the green areas protected by the ink. The com: position of this bath is Alcohol 100 parts,

(b) over an inking roller which applies a red dye to the spaces between the ink areas leaving the film as shown in Figure 2. In this example, the red dye is basic red N Extra (Kuhlmann) 8% solution in alcohol. The film is thoroughly washed with water to remove the excess of dye. (c) The filmis passed through a solvent cleansing bath of benzene and is brushed by roller brushes within the benzene to remove the ink areas, leaving exposed the clear green areas. The film at this stage has equal areas of red and green and is as shown in Figure 3.

The film is again led (when dry) through the printing machine which produces areas of greasy ink, as before, but this time the areas of ink occupy about two-thirds of thearea of the film as shown in Figure 4 and fall indiscriminately on the red and green areas previously formed.

After an interval for the ink to dry, the film is led in succession (a) over a bath which bleaches and dissolves out the red and green dye from only the clear spaces between the greasy areas, (b)v over an inking roller which applies a violet dye which dyes the spaces leaving the film as shown in Figure 5. The violet dyecontains- Crystal violet (4% solution in alcohol) parts, and malachite green (8% solution in alcohol) 20 v parts.

(c) The film is again led through a solvent cleansing bath of benzene and is brushed by rollerbrushes within the benzene to remove the ink areas and leave the completed screen as shown Alcohol parts,

Caustic potash (10% aqueous solution) 1 part, Acetone 10 parts,

Water 6' parts.

In the above example the ink areas applied and the resulting areas of color on the film are irregular in shape and arrangement but if desired the invention may be a plied to the production of a screen having regular areas (e. g. lines or squares). In one example of this form of the invention the roller has 25 chromium lines and 25 repellant mercurial spaces per millimetre at an angle of 23 to the axis of the roller and the same roller is used for both applications of the resist materialthe lines of the second application being applied at right angles to those of the first. The last applied color in this example occupies a total area on the screen equal to the sum of the areas of the first two colors whereas in the first example described the areas occupied by all the colors were substantially equal. It will be appreciated that'the present invention provides a method whereby any desired relation between the total area's occupied by the several colors-may be easily obtained, and thus any desired color balance between the colors can be attained.

It will be seen that by the above process it is possible to produce a multi-color screen having extremely fine elements or having elements of irregular shape or arrangement which need not in practice be so fine as those of regularshape.

I claim:-

1. The process of making a multi-color screen for color photography which comprises applying one color to the surface of a suitable base, ap-

plying a pattern of inky resist to the colored surface by means of a. printing surface having mercurial ink-repelling areas, bleaching the color from the portions of the colored surface unpro-' tected by the resist, dyeing the bleached portions a second color and removing the resist.

2. The process of making a multi-color screen for color photography which comprises applying one color to the surface of a suitable base.

applying a pattern of inky resist in irregular figures to the colored surface by means of a printing surface having mercurial, ink-repelling irregular areas, bleaching the color from the portions of the colored surface unprotected by the resist, dyeing the bleached portions a second color and removing the resist.

3. The process of making a three-color screen for color photography which comprises applying one color to the surface of a suitable base applying,

a pattern of inky resist to the colored surface by means of a printing surface having mercurial ink-repelling areas. bleaching the color from the portions of the colored surface unprotected by the resist, dyeing the bleached portions 2. second color and removing the resist, again applying a pattern of inky resist to the colored surface, and out of register with the pattern produced as above. by means of a printing surface having mercur al ink-repelling arew, bleaching the color from the portions of the colored surface unprotected by the resist, dyeing the bleached portions and removing the resist.

4. The process oi making on a suitable has a multi-color screen for color photography which comprises applying a coating of cellulose nitrate in solution to the base, dyeing the coating uniformly with one color, applying a pattern of inky resist to the coating by means of a printing surface having mercurial ink-repelling areas, bleaching the color from the portions of the coating unprotected by the resist; dyeing the bleached portions a second color and removing the resist.

5. The process of making on a suitable base a multi-color screen for color photography which comprises applying a coating of colored cellulose nitrate in solution to the base, applying a pattern of irregular figures of inky resist to the coating by means of a roller printing surface having mercurial ink-repelling irregular areas, bleaching the color from the portions of the coating unprotected by the resist, dyeing the bleached portions a second color and removing the resist.

' THOMAS THORNE BAKER.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2681857 *Sep 3, 1949Jun 22, 1954Polaroid CorpProcess for making a photographic color screen
US3782323 *Jun 9, 1972Jan 1, 1974Bowles Fluidics CorpSelf contained fluidic level sensor
US4247799 *Jan 30, 1978Jan 27, 1981Eastman Kodak CompanyCationic dyes absorbing different wavelengths
US4345011 *Sep 11, 1980Aug 17, 1982Eastman Kodak CompanyColor imaging devices and color filter arrays using photo-bleachable dyes
US4416961 *Feb 16, 1982Nov 22, 1983Eastman Kodak CompanyColor imaging devices and color filter arrays using photo-bleachable dyes
DE2903287A1 *Jan 29, 1979Aug 2, 1979Eastman Kodak CoEbene farbfilteranordnung fuer eine farbbild-abtastvorrichtung sowie verfahren zu ihrer herstellung
Classifications
U.S. Classification430/7
International ClassificationG03C7/04, G03C7/06
Cooperative ClassificationG03C7/06
European ClassificationG03C7/06