US1186000A - Color photography. - Google Patents

Description

UNITED STATES PATENT. OFFICE.

FREDERIG E. IVES, 0F PHILADELPHIA, PENNSYLVANIA.

. 7 COLOR PHOTOGRAPHY.

No Drawing.

T 0 all whom it may concern? 1 Be it known that I, FREDERIC EUGENE Ives. a citizen of the United States, residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented certain new and useful Improvements in Color Photography, of whichthe following is a specification.

This invention relates especially to color photography, although in part the novel features hereof could be employed in other arts. Particularly this improvement has reference to that system of color photography in which there are first secured two or other plu'ral number of color-selection negatives bysubstantially simultaneous exposure from substantially the same view-.

point, from which negatives a plurality of properly colored positives are secured and combined, so as to reproduce fully or approximately the natural colors of the original subject.

Within the scope of this improvement and within the art of color photography I intend to include the subject of motion pictures when the same are so taken and exhibited as to reproduce the original colors of the subject, since the representation of motion pictures in color, for example, on a screen, consists of a series of representations each of which may be considered as composed of two or other plural number of color positives suitably combined for the observer.

The present improvement has to do especially with the part of the process which follows the obtaining of the set of colorselection negatives. In other words, it relates to the problem of securing a multicolor photograph or other representation by the use of previously secured color-selection negatives.

Therefore, generally speaking, the object of the present improvement are to improve and simplify the obtaining from the colorselection negatives of multi-color pictures, or representations, of high and uniform quality.

The present improvement, as will be seen, proceeds in ageneral way along the lines of the gelatin relief system, and it is another object hereof to improve and render practical that system for the purposes of color photography.

Gelatin films, when treated by the bichro- Specification of Letters Patent.

Patented J une 6, 1916.

- Application filed March 13, 1915. Serial No. 14,223.

I will first describe in a general way the preferred steps contemplated in the present improvement, and will thereafter point out in detail one mode in which the improvement may be practically carried out. i

Assuming that proper negatives have been secured, the following principles for secure ing a multi-color picture may be followed: A gelatm film containing sensitive silver bromid may be employed as the starting point. Silver bromid film is, of course, capable of being printedby gaslight behind the negative. Before printing, however, the film is to be treated by a suitable light restraining agent consisting of some temporary non-actinic medium or .dye with which the gelatin will be impregnated. The sensitive film containing the restraining agent may be kept in stock, as it does not deteriorate. This agent is capable of so restraining the penetration of light as to minimize its action upon the sensitive silver salt. Without such restraint the full action of the light would result, as will be hereinafter explained, in an extremely high, contrasting and unsatisfactory relief. The film, which may have its support upon glass, celluloid, or the like, containing the silver bromid and the temporary light restrainer, as stated, will now be exposed behind the negative and. preferably through the rear glass or celluloid base, so as to avoid any need of stripping or transferring in subsequent processes.

After such exposure, by artificial light, the film will be put through the following steps or treatment, in which the temporary light restrainer will be automatically removed. The exposed film will be treated by the usual methods for developing the silver image. Such development, if properly carried out, does not affect the condition of the gelatin. Gelatin, however, in the presence of silver, has. the characteristic that it may be ren- Q 1,1se,ooo

dered insoluble by certain agents, which I will term desolublizing agents. This treatment selectively desolublizes the gelatin according to the silver image. Such step may be followed by washing or developing the gelatin in hot water, this serving to remove from the face of the film all of the gelatin which 'is not in intimate contact with reduced silver. There results a tenuous gela= tin relief. This relief may be rendered transparent by dissolving out of the silver image by usual methods. Having thus obtained from-each of the negatives an extremely tenuous, delicate and accurate gelatin positive relief of the image, the several reliefs may be employed to create color images by selective absorption of color, for example, by immersing in water-soluble dye of the proper colors. Having the several color images, they may be combined in any suitable manner to produce the final picture or representation. For example, the reliefs may be bodily superposed to build up a color photograph. Orthe several dyed reliefs may be employed simply as carriers,

each in turn being caused to give up its color image by imbibition into a common print member, thus again combining the colors into the finished picture. For color motion pictures any one of these systems of combining may be utilized.

In detail the following may be the procedure for carrying out the present process.

The negatz'oes.As before stated, the negatives may be procured in any desired manner, for example, by means of the cameras or apparatus disclosed in prior Patent Number 980,961 of January 10, 1911. For convenience I will assume the three-color system, although it is obvious that the present improvements could be employed in connection with the two-color, four-color or, other system. Assuming the three-color system, each of the three negatives will represent one of the so-called primary colors, red, green and blue. The corresponding complementary or secondary or printing colors will be respectively peacock (bluegreen), magenta (or pink) and yellow.

The gelatin fiZm-.-".The gelatin film could be a uniform layer of gelatin upon a substantially transparent support, such as glass or celluloid. In referring to gelatin I intend to include equivalent materials such as the other well-known colloids. There is a marketed sensitive film known as cinematograph positive film consisting of a thin, flexible, celluloid base, coated with gelatin containing very fine-grained silver bromid, which is adapted to serve the purposes hereof. If such film be employed, however, without restraining the action of light, its use would be unsatisfactory. The. silver image will develop to such an extent through the thickness of the gelatin film with an avfectly meet the specified requirements.

erage photographic negative that the gelatin in the subsequent desolublizing process will become insoluble practically throughout its. thickness in 'the shadows of the image before the exposure or development has been carried far enough to insure retaining the details in the lightshades of the picture, so that the resulting relief prints would be far too strong, contrasty and inaccurate for practical use in carrying out the present method. The coloring of the gelatin film with a temporary light restrainer is calculated to meet this difficulty. A light absorbing agent will be suitable which is adapted to oppose deep penetration of light, if such agent is substantially inert chemically and mechanically with respect both to the gelatin and to the silver bromid, and capable of being discharged in the subsequent developing or washing processes. The depth of penetration is slight over the whole image,

and proportional to the intensity of the light. Such light restraining agent is preferably a water-soluble dye of a color capable of effectively absorbing all of the light rays to which the silver bromid is most sensitive. For an ordinary sensitive film, which is particularly sensitiveto blue-violet rays, and

not rendered sensitive to green or red, a suitable agent is tartrazin dye. This is a soluble dye of a yellow color. 3.2 grams dissolved in one liter of water will very persensitive film should be immersed in the dye sufficiently to deeply stain or color the gelatin. Three minutes immersion should be sufiicient, followed by draining and drying. It will be understood that, as the tartrazin dye does not injure the gelatin or silver bromid or deteriorate the films, it may be in troduced in the emulsion, or subsequently, in the process of manufacture, and the'dyed films kept in stock, so that the photographer is relieved of the necessity of performing this step. If a film should be employed which has been rendered sensitive to red or green or other special colors, the tartrazin dye would not suflice, but some other dye would need to be selected capable of absorbing whatever kinds of light the films were sensitive to, without reacting to destroy either the primary blue-sensitiveness of the film or the special green or red or other sensitiveness which had been added by special treatment (with special. color sensitizing dyes).

Eaeposure.The sensitized and dyed film is to be exposed behind the negative. Since in the subsequent operation of dissolving out the unaffected gelatin the washing is done at the face, it is necessary to effect the exposure through the rear or transparent .base of the film. The very deep temporary The or portion of the gelatin adjacent to the glass or'celluloid support. By this arrangement the silver image will be confined wlthin such thin layer next to the base,and, consequently, in producing the rehef much the greater part of the original gelatin Wlll be washed away.

Development of silver image.After proper exposure the silver image is to be developed in any usual manner, which will not desolublize the gelatin. For example, ordinary metol-hydroquinone developer may be employed. This step should befollowed by very thorough rinsing and washing, so as to remove any tracesof sulfites or other active salts. These steps of develop ng and washing serve also to remove the temporary light restrainer or water-soluble dye. The gelatin, however, is still unafiected and consists of a layer of uniform thickness containing a rather thin silver image confined closely to the portion of the gelatin layer which is next to the transparent support.

Desolublizing the gelatin.This step consists in rendering insoluble all parts of the gelatin which are in intimate contact wlth the reduced silver. It is a fact that such desolublizing can be effected by treatment with certain agents, for example, the following bichromate-bromid solution: am, monium bichromate, 6.8 grams; potassium bromid, 6.8 grams; sulfuric acid, 6.5 cubic centimeters; water, 1 liter. Upon immersing the film in this solution the desolubl zing action proceeds as stated. The portions of the gelatin which are not in intlmate contact with reduced silver remain unaffected, and therefore soluble in hot water, whereas the portions which contain the silver are selectively rendered insoluble in degrees according with the lights and shades of the silver image.

The presence of the sulfuric acid inthe above desolublizing bath is of advantage in that, as the action of the bath proceeds, the reduced silver is bleached and under the dark-room lantern it is, therefore, possible to easily determine the completion of the action by the completely bleached condition of the silver image.

Deoelopment of gelatin relief-After rinsing the desolublized film in cold water, it only remains to bathe it in hot water to develop the gelatin relief by dissolving out the unaffected soluble gelatin. As stated, by far the major portion of gelatin is thus removed, leaving only an extremely tenuous layer or relief of insoluble gelatin, carried on the transparent base and preserving in full the variations of light and shade constituting the image. now remove the silver, which has served its purpose, and this may be eifected in any ordinary manner, for example, by transferring to a bath of sodium hyposulfite or It is preferred to visible or inappreciable relief. To redevelop or produce the image, it is only necessary to immerse each such relief in a dye bath of suitable color. Thus, the relief made from the negative produced by a green screen in the camera or a sensitiveness to green rays should be dyed the complementary color, magenta, and similarly with the remaining reliefs.

Combining the monochrome images.- Having the three reliefs dyed respectively magenta, peacock and yellow, they may be combined by bodily superposing them and mounting them, for example, upon a White back, thus giving a color photograph which may be handled as an ordinary photograph; or, successively, the three color images might be transferred by imbibition into a single gelatin layer upon paper; or other modes of combining them might be employed.

The importance of securing tenuity in the reliefs is great, but will not be attempted to be fully elucidated here. Such imperceptible lowness of relief not only insures the greatest accuracy in color gradations and quicknessand completeness of the staining operation, but yields a certain delicacy and brilliance of coloring, which is peculiarly necessary in building up froma plurality of monochromes a color photograph to be seen by reflected light. Any variation in color or gradations in any one of the monochromes does not merely affect the trueness ,of that monochrome, but destroys the effect It is obvious that in producing color photographs by the method of this application, the method may be employed throughout for all of the. monochromes, or, on the other hand, may be only partially employed, since part of the monochromes might be made b other processes and combined with that or those produced by the present process.

Coloring of the separate monoohromes. Whilea worker skilled in the art would be able to select the'proper coloring-materials for the three separate monochromes afterward to be combined, I would mention suitable materials for this purpose. For giving a peacock bluecolor to the relief made from the red selection negative may be used Bayers alizarin blu'e A S. For giving a magenta color to the relief made from the parts of Bayers alizarin rubinol R and rubinol 3. For giving a yellow color to the relief made from the blue selection negative may be used Bayers sulfon yellow B. It may, however, be desirable to produce one of the three components directly upon a paper backing, so that, when the other two color images are combined therewith by superposition, imbibition, or otherwise, the color photograph will be complete, backing and all. It has heretofore been proposed to positive prints into a peacock color.

employ an ordinary ferricyanid or blueprint for a basic monochrome of peacock color, but, as this requires daylight and is subject to the variations and delay thereof,

it is preferable to employ a method capable of use with artificial light. I have devised such a method which operates on the principle of converting ordinary silver bro%lid 1e following procedure devised by me produces with certainty extremely clear and brilliant peacock prints, and provides all desirable control both of density and contrast. After an ordinary bromid print has been well washed to remove the fixing agents, it is to be immersed in the following solution, freshly prepared, for from three to six minutes with constant rocking of the tray: 10% potassium ferricyanid 7 cu. cm.; 10% No. 8 acetic acid,'1l0 cu. cm.; 10% ferric ammonium citrate (brown), 7 cu. cm.; 10%

hydrochloric acid, 1 to 3 cu. cm., according to the degree of contrast and brilliance required. This effects the toning of the print to a deep, heavy blue with the whites considerably tinted. The print is then washed in water and transferred to such an alkaline fixing bath as the following: Sodium hyposulfite, .25 kilogram; sodium bicarbonate, 16 grams; water, 1 liter. The print will then be agitated in this fixing bath until the whites have perfectly cleared and the shadow details become perfectly differentiated. It will then be rinsed in water and placed for a few seconds in a solution of an acid, preferably a strong solution of oxalic acid, and afterward finally washed again in a thorough manner, drained and dried. This completes the production of the peacock blue print on paper. The employment ofacid toning bath, in connection with the subsequent steps of clearing by means of an alkali bath, and finally fixing in an acid bath, is believed to be of critical importance in meeting the necessity for securing clean, brilliant prints, with control of contrasts.

I believe I am the first to propose a photographic printing process comprising the incorporation, with the sensitive silver salt in a suitable film, of an actinic-light restrainer, whereby, upon exposure and development, the silver image will be confined to one side of the film. I also believe I am the first to propose a method of producing a photographic colloid relief print comprising the steps of incorporating in a suitably supported colloid layer witha sensitive silver salt an actinic-light restraining agent, exposing and developing the silver image, desolublizing the colloid by a suitable agent under the selective control of the silver image, and dissolving away the soluble colloid, whether or not the other and subsequent preferred steps before described be employed. The subsequent preferred step of dissolving out the silver image might in some cases be dispensed with, for example, if the colloid print is to be used merely as a temporary means of absorbing and carrying a color image intended to be transferred by imbibition to a color photograph. The subsequent preferred step of selectively coloring the colloid print might be dispensed with, if some equivalent be substituted, such, for example, as the pre-colo'ring thereof. The fullest embodiment, however, of the present invention requires the performance of all of the preferred steps mentioned in this paragraph, for the purposes of producmg multi-color pictures in the art of color photography. 7

It will thus be seen that I have described a process, with all necessary details, embodymg the prlnciples and attaining the objects and. advantages of this invention. Since many matters of treatment, manipulation, selectlon and proportion of ingredients, successlon of steps, and other details may be variously modified without departing from theprinciples involved, I do not intend any limltation to such details excepting, so far as set forth in the appended claims.

l/Vhat is claimed is:

1. In the art of color photography the method of producing a multi-color picture from a set of color-selection negatives, comprlsing the steps of incorporating in a suitably supported colloid layer with a sensitive silver salt an actinic-light restraining agent, exposing the same beneath one of the negatives, developing the silver image, desolublizing the colloid by a suitable agent under the selective control of the silver lmage, and subsequently selectively coloring the colloid and combining the color image thus produced with color images produced from the remaining negatives.

2. In the art of color photo raphy the method of producing a multi-co or picture from a set of color-selection negatives, comprising the steps of incorporating in a suitably supported colloid layer with a sensitive silver salt an actinic-light restraining agent consisting of an inert water-soluble dye of a color non-actinic to the silver salt, exposing the same beneath one of the negatives, developing the silver image, desolublizing the colloid by a suitable agent under the selective control of the silver image, and sub- 1,1se,ooo

sequently selectively coloring the colloid and combining the color image thus produced with color images produced from the remaining negatives.

3. In the art of color photography method of producing a multi-color picture from a set of color-selection negatives, comprising the steps of incorporating in a suitably supported colloid layer with a sensitive silver salt an actinic-light restraining agent, exposing the same ben eath one of the negatives, developing the silver image, desolublizing thecolloid by a suitable agent under the selective control of the silver image, said agent, consisting of a bichromate plus a bromid acidified to effect bleachin of the reduced silver, and subsequently se ectively coloring the colloid and combiningthe color image thus produced with color images produced from the remaining negatives.

7.4. In the art of color photography the method of producing a multi-color picture from a set of color-selection negatives, comprising the steps of incorporating in a suitably supported colloid layer with a sensitive silver salt an actinic-light restraining agent, exposing the same beneath one of the negatives, developing. the silver image, desolublizing the colloid by a suitable agent under the selective control of the silver image, dissolving out the undesolublized gelatin to leave a tenuous relief, and combining a color image produced in such relief with color images produced from the remaining negatives.

5. In the art of color photography the method of producing a multi-color picture from a set of color-selection negatives, comprising the steps'of incorporating in a suitably supported colloid layer with a sensitive silver salt an actinic-light restraining agent, exposing the same beneath one of the negatives and through the transparent support of the colloid so that the restraint of light confines its action to the side of the colloid layer next to its support, developing the silver image, desolublizing the colloid by a suitable agentunder the selective control of the silver image, dissolving out the undesolublized gelatin to leave a tenuous relief, and combining a color image produced in such relief with color images produced from. the remaining negatives.

6. In the art of color photography the from a set of color-selection negatives, comprising the steps of incorporating in a suitably supported colloid layer with a sensitive silver salt an actinic-light restraining agent consisting of an inert water-soluble dye of a color non-actinio'to the silver salt, exposing the same beneath one of the negatives and through .the transparent support of the colloid so that the restraint of light confines its action to the side of the colloid layer next I the image, dissolving out the undesolublized 'gelatin to leave a tenuous relief, and com- .bining a color image produced in such relief with color images produced from the remaining negatives.

7. In the art of color photography the method of producing a multi-color picture froma set of color-selection negatives, comprising the steps of incorporating in a suitably supported colloid layer with a-sensitive silver salt an actinic-light restraining agent, exposing the same beneath one of the negatives, developing the silver image, desolublizing the colloid by a suitable agent under the selective control of the silver image, dissolving out the silver image, and subsequently selectively coloring the colloid and combining the color image thus produced with color images produced from. the remaining negatives.

8. In the art of color photography the method of producing a multi-ecolor picture from a set of color-selection negatives, com-v prising the steps of incorporating in a suitably supported colloid layer with a sensitive silver salt an actinic-light restraining agent, exposing the same beneath one of the negatives, developing the silver image, de: solublizing the colloid by a suitable agent under the selective control of the silver image, dissolving out the silver image, dissolving out the undesolublized gelatin to leave a tenuous relief, and combining a color image produced in such relief with-color images produced from the remaining negatives.

9. In the art of color photography the method of producing a multi-color picture from aset of color-selection negatives, comprising the steps of incorporating in a suitably supported colloid layer with a sensitive silver salt an actinic-light restraining agent, exposing the same beneath one of the negatives, developing the silver image, desolublizing the colloid by a suitable agent under the selective control of the silver image, dissolving out the silver image, dissolving out the undesolublized gelatin to leave a tenuous relief, and combining the same in colored condition with color images produced from the remaining negatives by superposmethod of producmg a multi-color picture ing such colored relief bodily with the other portion of the picture.

10. In the art of color photography the method of producing a multi-color picture from a set of color-selection negatives, comprising the steps of incorporating in a suitably supported colloid layer with a sensitive silver salt an actinic-light restraining agent, exposing the same beneath one of the negatives, developing the silver image, desolublizing the colloid by a suitable agentunder scribed.

11. In the art of color photography the improvement in making multi-color pictures from a set of color-selection negatives, which consists in producing colloid reliefs from one or more of such negatives by impregnating a sensitive gelatin silver bromid film with a suitable temporary actinic-light restraining agent, exposing such film behind the negative and through its rear or base, developing thesilver image by any suitable method, selectively desolublizing the gelatin by a suitable desolublizing agent which operates in the presence of reduced silver, and dissolving out the silver image and the soluble gelatin, thus affording a gelatin relief; coloring each of such reliefs by select'ive'absorption of dye of the corresponding color, so as to produce monochrome color images, and, finally, suitably combining the monochrome color images produced from all of said set of negatives into a single multi-color picture.

12-. The method of producing a photographic colloid print comprising the steps of incorporating in a suitably supported colloid layer with a sensitive silver salt an actinic-light restraining agent, exposing and developing the silver image, and desolublizing the colloid by a suitable agent under the selective control of the silver image.

13. The method of producing a photographic colloid print comprising the steps of incorporating. in a suitably supported colloid layer with a sensitive silver salt an actinic-light restraining agent, exposing and developing the silver image, desolublizing the colloid by a suitable agent under the se lective control of the silver image, and dissolving out the undesolublized colloid.

14. The method of producing a photographic colloid print comprising the steps of" incorporating in a suitably supported colloid layer with a sensitive silver salt an actinic-light restraining agent, exposing and developing the silver image, desolublizing the colloid by a suitable agent under the se lective control of the silver image, and dissolving out the silver image.

15. The method of producing a photographic colloid print comprising the steps of incorporating in a suitably supported colloid layer with a sensitive silver salt an actinic-light restraining agent, exposing and developing the silver image, desolublizing the colloid by a suitable agent under the selective control of the silver image, and dissolving out the silver image and the undesolublized colloid. V

16. Method of producing tenuous colloid relief prints which consists in impregnating a sensitive gelatin silver bromid film with a suitable temporary actinic light restraining agent, exposing such film behind a negative and through its rear or base, developing the silver image by any suitable method, select-ively desolublizing the gelatin by a suitable solublizing agent which operates in the presence of reduced silver, developing in hot water to remove the soluble gelatin, thus affording a gelatin relief.

In testimony whereof, I have affixed my signature in presence of two witnesses.

FREDERIG E. IVES. Witnesses:

FIRED C. MARTIN, ALFRED THOMPSON.