US1325204A - And william v - Google Patents

Description

C. RALEIGH AND W. V. D. KELLEY, coLoR PHOTOGRAPHY.

APPL-ICATION FILED DEC. 20l |916.

' Patented Dec. 16,1919.

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l CHARLES RALEIGH, OF JERSEY CITY, NEW JERSEY, lAND WI'JLIAIM V. D. KELLEY, OF

BROOKLYN, NEW YORK, ASSIGNORS, BY MESNE ASSIGNMENTS, TOy PRIZMA INCOR- Y PORATED, A CORPORATION OF MAINE.

Be it known that we, CHARLES RALEIGH, a subject of theKing of Great Britain, and WILLIAM V. D. KELLEY, a citizen -of the United States, residing at Jersey City,`

county of Hudson, Statehof New Jersey, and Brooklyn, county of Kings, State of New York, respectively, have invented certain new and useful Improvements -in Color Photography, of which the following is a full, clear, and exact specification. VThis invention relates to photography in colors, and has particular reference to the reproduction of motion pictures in natural colors. The object of the invention is to provide a method, color screen, and image produced thereby, which while'iiltering the light to produce the various color value records on the emulsion-will` also asclosely as possible approximate the conditions of a colorless 'transparency in simultaneously passing the light.

In French Patent No. l479,921, granted February 2,9, 1916, there is disclosed a method, screen, and image, wherein an ex-` posure to white light and a color value record are superposed on the same section of emulsion, whereby the several component color records of the cycle are intensied or leveled without destroying the difference in color value. According to said patent, there is a clear section associated with each fundamental color filter section 'so that each emulsion section is exposed both to\the color section to, obtain the color value record, and to the clear or intensifying sector to obtain black and white values. By such apparatus and method, the resulting pictures are soft and pleasing in color, and owing to having been intensified, are as complete in detail and depth as though an ordinary exposure made without color lters. Y

This invention relates to the same subject, but embodies an improvement in the method,

screen, and image, whereby a sudden transition from the color section to the clearI section, or vice versa, -is avoided by means of a` graduated screen or filter, each section preferably uniformly shading from practically clear (or open) to the full color depth for that section, or the color uniformly weakens lto white or clear.- This is useful in graduat-f ing the proportions o f color and clear in "each section, and also in balancing two,A

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three, four or'more sections. The exposure more of the screensections may be made-in this way, although it is preferable that all bel so made. .Suicient color value differences A are thereby obtained between the images of a series so that the original colors are .reproduced when projected; less light is required to obtain a good exposure than with known screens made up of uniform solid color; the series of pictures on the film are very much more uniform in appearance and'intensity than where solidl screen colors are used; andv the'light admitted to the emulsion section at all times favors the desired color value.

The screen carrying the filters ismovable specification of Letters Patent. Patented Dc. 16, 1919.

Application led December 20, 1916. Serial No. 137,943. I

for both still and motion color photography.

The simplest form is a revolving screen as herein illustrated, but it may reciprocate, or be embodied 'on an endless band, or in any other way, so that the filter screens move Figure 1 is a perspective view of a four color screen embodying one` form of the, invention, and

Fig. 2 is a cross-section. The invention can be carried out in various ways, of which only a few examples are mentioned herein. For example, the filters can .be made of gelatin and colored or dyed so that the color desired is of f'ull depth at `during the period of exposure. In a three f one end and shades off tofpractically no color, A

or but very little color', at-.the other end.

Examples of such shading are shown in Fig. l, wherein B is the blue section which is darkest at the bottom and shades to practically no color at the top, R is the red section shown as darkest atithe top and shading to practically no color at the bottom, G is the green section shown as darkest at the top and shading to practically no color at the bottom, while Y is the yellow section which is darkest at the right and shading to practically no color at the upper edge. K are the opaque sections between each lter section, which cover the emulsion while it is being changed.

Another filter can be made of pot-metal glass, or flash glass, that is,l glass having color throughout its structure, or on one surface. These are then ground down to a wedge shape, so that the density of the color is greatest at the thick end and less at the thin end. Effects due to diffraction or re fraction, owing to the wedge shape of such filters, can be avoided by applying thereto similar but reversed wedge shape filters of l the same kind of clear glass, so that the whole filter has a uniform indexk of refraction, but still is graduated as to color, being heaviest at -one end and with little or no color at the other, as in Fig. 2.

Also, in case it is desired to compensate for a preponderance of color rays in the light, as for instance excessive blue violet in arc light, the clear portions can lbe given a graduated yellow tint, either o'f graduated yellow colored gelatin, densest at the clear portion of the filter, or by using a wedge shape colored glass similarly disposed. Anexample of a wedge shaped glass filter section compensated for yellow is shown in Fig. 2, in which M represents the color section ground down to a point at l?, and having combined therewith a compensating reversely arranged wedge at the thick end opposite the thin end of the color section. Thus M may be a section of any 'one of the filters B, R, G, Y, above described, and O a section of a yellow colored compensating filter associatedv therewith for correcting a preponderance of blue violet in arc light. This is especially desired in casethe panchromatic film emulsion is over sensitive to violet rays, as is frequently the case. It will be understood that where yellow is used in this manner it is merely as a corrective means, and not for color values, and while preferably used on all the filter sections to correct for color need not neeessarily be so used. It will be obvious that screens embodying this invention may be made up in many ways other than herein explained, and that they may be variously mounted on movable supports either rotary, or reciprocating, or movable bands, without departing from the scope of the invention.

It will be understood that the manner of applying the broad features of this invention is not restricted to the specific forms herein described. For example, it may be desired to vary the screen section from full color at one end to no color in the middle and then to` full color at the other end, or the full color may be in the middle and shade toward each end to no color, or the clear sections may merge from one side to one fundamental color and from the other side to another fundamental color. rllhe invention can be used both in taking and proj ecting. The color value negatives obtained in taking are developed and printed in the usual manner, and then projected either with the same screen used in taking, or with a correspondingly colored screen without the clear portions.

t will be seen that such arrangements and many others can readily be made without departing from the scope of the appended claims.

vWhat we claim is l. The method of recording a color value, which consists in exposing the same panchromatic emulsion to light varying continuously during the exposure between a fundamental color component and substantially white light.

2. The method of recording a color value, which consists in exposing the same panchromatic emulsion to light varying oon tinuously during the exposure between a fundamental color component and light y compensated to be substantially free of preponderating color constituent.

3. The method of recording a color value, which consists in exposing the same panchromatic emulsion to light varying continuously during the exposure between a fundamental color component and white light compensated for blue violet contained therein. y A

4. The step in making photographic records, which consists in exposing each of a predetermined succession of panchromatic emulsion sections through a different color filter, each color filter continuously varying between a predominant component and light substantially free of preponderating color.

5. The step in making photographic records, which consists in exposing each of a predetermined succession of panchromatic emulsion sections through a different color filter, each color filter continuously varying between a predominant component and light compensated to be substantially free of preponderant color constituent.

'6. The step in making photographic records, which consists in exposing each of a succession of panchromatic emulsion sections through a different color filter, each color filter continuously varying between a predominant component and' light compensated by yellow for blue violet.

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7. In motion picture color photography employing a plurality of color value images in recurring cycles, the step which consists in recording each image of a cycle by light varying continuously during the exposure between a fundamental color` component and light substantially free of preponderating color, the fundamental colors in each cycle forming substantially White.

8. In color photography, the method of increasing the density of a record, Which consists in recording a fundamental color value While simultaneously varying White light value.

9. In color photography, the method of increasing the density of a record, which consists in recording a fundamental color value While continuously weakening said color value and increasing the black and White values.

recording a 10. In color photography, the method of increasing the density of a record, which consists in recording a fundamental color value While continuously and inversely varying the relative intensity of the color and black and White values.

11. In color photography, the method of increasing the density of a record in a given time7 which consists in recording the color values by constantly decreasing a fundamental color and constantly increasing black r and White Values.

In testnnony whereof We aiix our signa,u tures 1n presence of tWo Witnesses.

CHARLES RALEIGH. WILLIAM V. D. KELLEY.

' Witnesses:

FREDERICK N. EsHER, NEALE RANsoM.

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