US1935477A - Process of color photography - Google Patents

Description

Nov. 14, 1933. I M. MARTINEZ 1,935,477

I PROCESS OF COLOR-EKOTOGRAPHY Filed Feb. 25, 1.930

Jwuentoz Patented Nov, 14, 1933 PATENT OFFICE 1,935,417 mocsss or cocoa morooasrny Michele Mai-tines, London, England, assignor to A. H. Johnson & -Co.'(Paper) Limited, London,

- England Application February 25,

1930, Serial No. 431,210, I

and in Great pram July 15, ms

1 Claim. .-(o1. 95-2) The invention consists in removing the color elements in the parts of a color photographic. surface which have not been afiected'by light, any black silver formed by development being re- 6 moved wholly or in part either simultaneously with, or subsequently to, the other removal. I In accordance with the invention color ele-, ments may be combined with light-sensitive layers or emulsions in various ways and forms, 10 namely: (a) The light-sensitive layers or emulsions themselves may contain color media diffused throughout or dissolved in them; by color media I mean either substances actually colored or po- 16' tential colors, that is to say substances, colored or otherwise, which will change or acquire 'or produce'a color on suitable treatment.

Y (b) The light-sensitive layers or emulsions may contain in suspension finely subdivided or grain- 20 like particles of one color or of more than one color, whether such particles are actually themselves light-sensitive or not.

(c) The light-sensitive layers may contain a color medium diii'used or dissolved throughout as 25. in (a) and particles of one or more other colors S p nded in them as in (1)). (d) The light sensitive layers or emulsions are 7 provided with a separate layer containing ditfused color media or suspended color particles 30. under or over them, or both.

Photographic materials provided with color elements in any of these forms are, after exposure in a camera, and simultaneously with or s'ubsequentto, development or fixing or both,

Id treated in a way designed to remove the color particles which have not been aflected by light or the color media or particles immediately adjacent, over or under the parts which have not been affected by light, the light-sensitive ele-.

'40 ments themselves aiiected by light being,afterwards or simultaneously removed wholly or in The object is attained by hardening in a known manner, simultaneouslyv with, or subsequently to,

' development, the gelatine corresponding with the.

exposed parts, and then dissolving .by means. of .hot water, acids or alkalies the'gelatine parts leit unhardened, when also the color media or particles there present will be removed together with the gelatine, or thdse lying beneath in separemove the gelatine itself, its hardening being suflicient to retain-in, over or under the parts that are hardened color media, particles or potential colors; because such hardening prevents or considerably retards the penetration of agents, so whether simply water or appropriate solvents, which may be applied to dissolve out of the softer parts, such color, media, particles or potential colors.

, and cinematography, in the manner described.

As instances of some color particles which can be used as hereinbefore mentioned I will name colored salts of silver, such as silver erythrosinate, silver ferricyanide .or silver chromate; colored salts of mercury or of mercury and silver; other metallic colored salts, such as nickel dimethylglyoxime or copper benzoin-oxime; colored sulphides and oxides; the special sulphide of cop- 80. per known as copper-indigo; cmruleum; cobalt blue; Thnard blue; other mineral colors; metallic resinates and the like, especially those which are likely to combine more or less completely with, or to be adsorbed by silver halides. Colcred, particlescan also be made from animal or vegetable colorlng matters, such as byprecipitating with alcohol'aqueous solutions of water-soluble dyes and dextrin or gum arable, or both, or

by precipitating with water alcoholic solutio of spirit-soluble dyes with or without such or r as dammar, guiaicum orinastic. Color elements to be applied as'diflused coloration in any suitable medium or in the sensitive layer itself may be furnished by solutions'in appropriate solvents of coloring matters or dyes suitably selected from among those, the composition of which is not such as to destroy or hamper the sensitiveness and permanence or capacity for development of light-sensitive compounds and at the same time are not themselves del stroyed ,cr aifected in any unrequired way by the chemicals usually used in photographic treatments. For instance, for red, pure cai'mine in ammonia ,solution. erythrosine, iodo-eosin, all quinolinfe 7601013 and severalofthc alizarine derivatlveszf for yellow also alizarine and quinoline colors, tartraaine, carthamine and many others;

for blue, compounds derived from loswood and indigiitin, alizarine blue and sevno eral more; besides others already mentioned as suitable for colored particles. I

Potential colors, in the meaning previously explained, may be furnished by any compound, salt, extract or other substance which may be made to yield a color reaction or preferably a colored precipitate of the required hue. For instance a nickel salt which may be treated subsequently with dimethylglyoxime or other reagent, or vice versa; a copper salt which may be treated subsequently with benzoin-oxime, or vice versa; benzidine; logwood extract; ferric salts; .ozand fi-naphthylamine; leuco-compounds; uranium salts and many others.

The invention may be carried out in a number of ways, which may be grouped in a few.

to be considered as types and several varieties of each type. v

'The accompanying drawing represents cross sections through supports coated with various materials and are drawn to an exaggerated scale.

Class A.-Embodiments wherein color media are diffused or suspended throughout several layers of sensitive emulsions coated on both sides of a thin, transparent support.

Example 1.A thin film of celluloid or other transparent cellulose material S (Fig. 1) is coated on one side with an ordinary emulsion El, rather slow in comparison with that used for the coatings which are to be applied on the other side, and thinned by addition of 40-50 per cent. of its volume of a saturated solution, in aqueous gelatine of! per cent. strength, of the dye, mainly used as indicator, known under the name of Brilliant cresyl blue. The addition of this dye to an emulsion will reduce the speed of the emul- *sion, which must be taken into account. In a slightly alkaline medium, such as a silver bromide emulsion, the dye mentioned is yellow, and remains ,yellow until an acid bath is applied, in which it changes to a good blue. The other side of the film is coated firstly with an ordinary fast silver bromide emulsion E2, thinned by' addition of 30-50 per cent, of its volume of an aqueous solution ofplain gelatin in which, while it'is hot, there is dissolved as much tartrazine and quinoline yellow asit can dissolve; this emulsion is rendered ortho-chromatic by the addition of the usual sensitizers for yellow and green. Over this layer there is coated a second layer E3, which is an ordinary silver bromide emulsion thinned by addition of 40-60 per cent. of itsvolume of a saturated solution of erythrosine in water containing also 7 per cent. of gelatin; this emulsion is made red-sensitive by addition of the usual sensitizers for the red end of the spectrum, and is the fastest of all the emulsions used in this instance. The usual hardening agents may be added to the present emulsions. The material is exposed in a camera with the surface bearing the single layer E1 facing the lens. On exposure, the layer E1, being an ordinary emulsion, is affected only by white and blue rays and by the blue components of the green rays,

while E2 is aifected by white rays, green rays and yellow rays; should this E2 be also red-sensi-,

tive, which would do no harm, it would be affected also by red rays. Blue rays would not afiect this emulsion because they would be absorbed by the yellow color of the El emulsion. The layer E3.

will be affected by white rays and red rays-only, because the blue rays will not reach it, and to yellow rays it is not sensitive. The crossed parts in Fig. 1 show where the layers are afiected by .the light rays, indicated at the left hand of the figure, where Wh stands for white rays, B for blue rays, G for green rays, Y for yellow rays, R for red rays and Bla for black or no rays whatever. The treatment to be applied to this material is development in any of the usual ways, and then the application of such a bath as is already kdiown to have the effect oihardening the gelatine of.

an emulsion in the parts wherein blast: silver has been developed. Developers are also known which, in one single treatment, produce both the development of the, exposed parts and at the same time the hardening thereof. The pr ferred prescription is the following, made in two steel:

l Equal parts of the first and the second solution are mixed for actual use. After this bath the material is transferred to a bath of warm water, or to a cold bath of an acid, wherein all I the gelatine parts oi the emulsions which have not been affected bylight, the silver halide remaining therein and the colorations also contained therein, are all dissolved and there remains a negative picture in black which retains a color picture in itself, see Fig. 2. It is now sufficient to transfer the picture to a bath, made according to any of the known prescriptions, for the purpose of reducing and dissolving black silver, such as acid permanganate, acid persulphate or hypo-ferrloyanide, the picture being 'kept in the bath until thecblor picture is plainly visible. The black silver can be removed entirely, or, preferably, can be removed only partly, according to taste, it being always advisable to leave a little of the black silver so as to soften the briiliancy of the colors. In the acid reducing bath or'in a subsequent acid bath the dye in E1, where it remains, is changed to blue.

The picture obtained in this way is a peculiar one, inasmuch as it is a negative insofar as the blacks and the whites are concerned, but is a positive insofar as the colors are concerned, although the luminosity of the latter is inverted;

that is to say in this negative, whilst the blacks will appear white and the whites will appear black, a pale blue will be represented in a darker shade of blue and vice versa, and so for all colors. 01' course, in printing on a material of similar characteristics the black and whites and the im- 1 ers oi sensitive emulsion, coated on one side only of a support, potential colors being most suitable for use in this class.

Example 2.-A transparent support 8 (Fig. 3) which may be celluloid, other cellulose film, glass, paper or the like, is coated firstly with an emul sion E1 which is panchromatic and contains such an agent, preferaby colorless, as will give a red color or red precipitate on suitable treatment, for instance either a nickel salt or dimethylglyoxime or e-benzildioxime. The nickel salt may be dissolved throughout the emulsion or suspended therein, ior instance in the form of a carbonate or a phosphate. This layer of emulsion, as indeed all other layers, may be extremely thin so that all the layers taken together are hardly any thicker than a single ordinary emulsion, because the function of those layers is simply to retain colorations or the agents therefor. Over the first layer there is applied a second layer of emulsion hi2, faster than the preceding one and ortho-chromatic and contain =1. in suspension or difiusion, an agent which will give a yellow coloration or precipitate with a suitable reagent; for instance ammonium molybdate, which will give a yellow precipitate on treatment with a phosphate; or a cobalt salt which will give a yellow compound with an all nitrite; or a uranium salt which will give a yellow precipitate with an alkali carbonate. Over this layer there is coated again a third layer of emulsion E3 which this time is only an ordinary one and is faster still than the preceding ulsio'ns. This layer contains, in suspension or difiusion, an agent which will give a blue coloration or precipitate under suitable treatment: for instance a solution oi benz idine, which will give blue on treatment with potassium ferricyanide or other color developer; or a solution of logwood extract or haamatoxylin, which will give a blue precipitate with ferric salt or some other salt. Over this emulsion there is coated still another layer E4 of the same ordinary emulsion, that is of the same speed as'ES, but specially intended for producing a contrast. This last layer contains J a mixture of all the agents alreachl used in the previous emulsions. The material so composed is to be exposed in an ordinary camera, preferably through the support side, that is with the "glass or celluloid facing the lens. In Fig. 3 the crossed parts in each emulsion represent the parts which would be afiected by light rays indicated to the left hand of the figure. There must be noted the gradations of the affected parts, which gradations are producedby the resistance to the penetration of the rays oflered by the several layers, and by the different color sensitiveness or the layers themselves. A compensating filter or an asculin filter may be used in the lens.- After exposure the material. is developed and hardened, preferably in the developer bath described in Example 1, the hardening being applied for the purpose of retaining in the hardened parts the various agents cmbodied in the emulsions. Actual removal of the gelatine in the unhardened is optional, as thevariousagentscanbesoembodledastobe washed away by water, or by suitable agents, applied afterwards, or simultaneously. In most cases, however, the soda of the bath recommended as developer is sufllcient to extract and dissolve all the agents mentioned. from the parts or the gelatine that are not hardened. After this operation all the various reagents mentioned, which are for the purpose of developing the col- 7 orations, are applied either in the form of a bath, or by'application by a brush, or by cotton wool. These reagents may be mixed together or used separately. It is preferable first to apply the various reagents in a solution in which they are all dissolved together, and afterwards to ap- 5 ply separately any one which may be required to enhance a particular color everywhere in the picture, or only locally in parts thereof. Fig. 4 shows the parts where the color reaction would be obtained; for it must beobservedthat, although all the parts which are crossed in Fig. 3 have been hardened, the color reaction can only happen where each layer is left uncovered by the superimposed layerss The emulsion E 1 containing all agents, will yield black where the 90 agents are left. This emulsion could also be used without any agent, relying for black on leaving some reduced silver, which ispresent at that point in the largest'quantlty. It is now sufflcient to remove wholly or partially the black silver to obtain a clear view of the color picture, which is a negative in the blacks and whites and a positive in the colors. The removal of the silver may occur before, or simultaneously with, the development of the colors. 1 86 By inverting the order oi the layers given in this example and their relative the material could be used for exposure from the coated side, in which case the colors could be developed in the parts left soft, soon after, or other 195 with, development and hardening.

Example 3.-As an instance oi how typical example maybe varied I will outline an em o ment wherein some of the characteristics c4 EX- ample 2 are combined with some oi the characteristics of Example 1. A support is coatedwith a first layer of a red-sensitive emulsion containing an agent for red as mentioned in the preceding example; then with anortho-chromatic emulsion, containing an agent for yellow as mentioned in Example 2, and lastly with an emulsion ex:- ectly like the E1- of Example 1. Treatment to be applied is development and hardening of the ex-' posed parts, and then development of the colors in the parts hardened; this treatment will only act on the first two emulsions because the last one has no potential color and only changes its yellow color to blue in an. acid bath. Such a material would yield a picture that is a negative in the blacks and whites and a positive in the colors.

Various other sequences of layers and ways of grouping are possible with potential colors; for instance in Example 2 emulsion 154, Fig. 3, can

be made the slowest and emulsion E1 the fastest,

exposure of the material being made with the g;

coated side facing the lens. This variation would be specially suitable for coating papers iii-'- tendedto beewlththe coated sideagalnst a first picture, obtained by camera exposure of material prescribed in- Example 2. 3;

Instead of potential colors, such colored particlesmaybeusedinthformofsalts in the emulsion, as may be dissolved by any appropriate agent, in which case it is not necessary to remove the gelatine. when this is the case,

its,

" the hard parts; in this case dextrin or gum arabic or glycerine need not be added to the emulsions.

Variation to Class B One most important variation is also possible when potential colors are concerned. This consists in coating a support, such as paper or the like, with the reagents that are required to produce the colors in a material, such as for instance that described in Example 2. The reagents may be applied to the support in a suitable medium, for instance gelatine, gum arabic, dextrin or the like. Paper or other support bearing on its surface the various necessary reagents all mixed together, may be dried and kept for use when necessary. I will call this a positive reactive paper. The potential color photographic material, for instahce that described in Example 2, is developed and hardened in the developed parts as described, and then the agents or potential colors contained therein are dissolved from the soft parts oi the gelatine; no actual development of colors is applied. it sheet of the positive reactive paper is brought in contact with a material made as described in Example 2 while the latter is in a wet or damp state, the contact being maintained, preferably under pressure, for a short time, with the result that the color reaction will then occur between the material of Example 3 and the paper, and the color picture will appear on the latter. Thus prints may be obtained simply by contact, without using light-sensitive layers or resorting to exposure to light or any other treatment, except perhaps the washing in plain water of the positive reactive paper for the purpose of dissolving any reagents left therein. Only a limited number of copies could in this way be obtained from one picture, according to the quantity 0! agents incorporated in the layers of the material of Example 2, or or any other example, in accordance with this invention, suitable for the purpose.

It should be added that, generally, the addition of the various color media slows down to the required degree a fast emulsion, so that it would be advisable, when practising any of the examples given, to start from a single emulsion and to divide it into so many parts as are the layers to be coated on a support, and then to make to each part of the necessary additions.

Also it must be kept in mind that 'the color media must not necessarily be incorporated in the emulsions; they may be applied as separate coatings between or over or under the relative layers of emulsion, when it will be found that they interfere less than otherwise with the sensitiveness and selectiveness of the emulsions, especially ii alcohol is used'as a medium for the sap-=- arate coating or" color media.

Finally, whenever, in any embodiment of the present invention, several layers of emulsion and color media are to be applied on a single support, separate supports may be used, instead, for any or each of the separate layers of emulsion or color media, and the various supports, so coated, may be used all together in the form of a pack, orin any other suitable way, andthey may be separately subjected to the necessary treatments.

Having now fully described the nature of the said invention and the best means I know oi carrying the same into practical effect, I claim:-

A process of color phot aphy which consists in coating 9. surface wit at ast one photo-sensitive layer containing otential colors, then exposing the coated surfac to the action of light, then removing potential colors from those parts which have not been affected by light, and then applying the surface to a. support containing at least one agent adapted to develop the colors required from; the potential colors remaining on the surface.

MICHELE MARTINEZ.

Hill

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