US2328368A - Color photography and cinematography - Google Patents

Description

Aug; 31, 1943. A. G. TlLJLL 2,328,368

COLOR PHOTOGRAPHY AND CINEMATOGRAPHY Filed March 19, 1941 FIG. 2.

Inventor flitorn Patented Aug. 31 1943.

UNITED STATES PATENT OFFICE COLOR PHOTOGRAPHY AND CINEMATOGRAPHY Alan Gilbert Tull, Purley,

Latta Syndicate Limited,

British company England, assignor to London, England, a

Application March 19, 1941, Serial No. 384,180 In Great Britain March 27, 1940 Claims. (o1. 95-2) The present invention relates to methods of producing multi-color photographic records, and more especially records made through the processing of a photographic material such as that disclosed in my co-pending application filed Oc- I tober 24, 1941, Serial No. 416,407, which is a division of the present application, whereby to produce either natural color positives, or master records, either negative or positive, which are not necessarily natural color records of the original subject but from which natural color prints may be made. i

The invention has for its principal object, to

provide a simple, relatively inexpensive and satisfactory method of producing a multi-color photographic record on a material comprising a sup port carrying at least three silver halide emulsion layers, of which layers the onenearest-the support is difl'usely dyed with a dye capable of being processed by the silver dye-bleach process to form a color image, while the other layers are substantially colorless. t

Briefly stated, the process constituting the present invention, as applied to such a material comprises its exposure, and development or the ladeposits in its layers which are dyed layer by dye destruction, at any stage at which there is asilver image in said diffusely dyed layer.

Various specific modes of carrying out the inf vention are described more fullybelow, both as regards processing by reversal and by negative technique to give a negative record from which copies may be made by printing; and in order that the invention may be the better understood, reference is made to the accompanying drawing In the iorm shown in Fig. 1, a Celluloid support I is coated with an emulsion layer 2 which is blue sensitive and diflusely dyed yellow, followed by a green sensitive layer3, and a red sensitive layer 4. A red or green absorbing filter layer 5, which is destroyed or removed during the processing of the material may be required if the layer 4 is also green sensitive.

. In the form shown-in Fig. 2 a transparent support i, is coated with a. red sensitive layer 6 which is colored yellow,'followed by a green sensitive layer 1 and a blue sensitive layer 8. A yellow filter layer 9 is preferably interposed between the layer and 8"while ared filter layer It may be provided between the layers 6 and I. In another form the layer 6 is green sensitive and diffusely colored m'a'gentathe layer 1 is red sensitive andflayert blue sensitive. In this case the filter'layer 10, if required, is of green color.

In theproduction of duplicatecopies or prints from master positive or negative records produced on the'material shown on Fig. 2, in which the'blue sensitive layer is processed blue-greenas "described below while the middle layer is colcred either magenta or yellow according to whether the lowermost layer is diffusely dyed yel- 'lowfiormagenta respectively, copying is effected on alsimilar type material.

iii the case of 9. copying material the support ay-be or translucent or opaque material such per forming the-final support of the colored Th rst step in the processing of the material alterexposure is to develop the latent images in the different layers to silver. This is preferably performed in an ordinary negative developer,

constituting a part of this specification, in which which in the case of reversal processing contains a proportion'of a silver solvent such as potassium thiocyanate. Further steps are dependent on whether a positive or negative is to be produced. In the case of the production of a positive by reversal the form of material indicated above in Fig. 1 is exposed through the support and after developmentiurther steps include the conversion of the residual halide into an intermediate in the formation of a colored image by chemical toning and the selective destruction of the dyestufi in the bottom layer at the points occupied by the developed silver therein. In my co-pending application filed February 10, 1941, Serial No. 378,301 a process of producing such an intermediate is described wherein the conversion is performed directly in a bath containing a substance capable of forming a complex with the halide which complex is then converted into the intermediate. Thiourea in acid solution is a well known reagent for the production of color images by the silver dye-bleach process and it has been found that the conversion bath given in the aforesaid application No. 378,301 may be modified by the addition of an acid such as sulphuric acid and preferably also of hydroquinone without modifying the characteristics of such bath as regards the conversion of' the residual halide into a silver ferrocyanide and that such modified bath then serves also for the selective destruction of the dyestuff in the bottom layer.

As a result of the processing steps so far de scribed there are in the top two layers reversed image deposits of silver ferrocyanide or a complex thereof and in the bottom layer a reversed yellow color image produced by the selective destruction of the dyestufi at the point occupied by the silver image therein; there may also be a deposit of silver ferrocyanide but this is unaffected by the further processing.

As described in my co-pending application filed February 10, 1941, Serial No. 378,302 such intermediate images may be treated in a mixed toning bath preferably containing a ferric salt and a uranium salt whereby a deposit of Prussian blue is formed in a surface layer and a deposit of uranium ferrocyanide below forming a red'image. It has been discovered that by suitable control in the proportions of the constituents of the mixed bath, particularly in the amount of potassium bromide, as explained in the aforesaid application No. 378,302, the effect of the mixed toning bath may be confined to the top two layers of the material so that any silver ferrocyanide which may be in the bottom layer is unailected. The final step is to remove silver and silver salts in the several layers in Farmer's reducer or in the modified form of this reagent mentioned in said last mentioned application.

Inasmuch as the uranium ferrocyanide image is not fully satisfactory as the magenta image of a three color record, preferably the material is treated in a solution of a soluble zinc salt which converts the uranium salt into zinc ferrocyanide which is dye-toned with a suitable magenta dye as described in my co-pending application filed April 3, 1941, Serial No. 386,744.

In the processing to form a negative master record on any of the forms of material referred to above after development of the latent images, the silver images are converted into silver ferrocyanide or other suitable intermediate in view of the further processing steps, without fixing the layers. To this end thefollowing bleach may be used:

. Cubic centimeters Potassium ferricyanide 10% 12 Ammonia (.880) 1.2 Water to 60 Further steps include the treatment of the material in a mixed toning bath, particularly one containing a ferric salt and a uranium salt,

and so controlled that only the two outer layers.

Calcium hypochlorite gms 2 Glacial acetic acid ccs 2 Water to -ccs 200 The uranium ferrocyanide image in th middle layer may, if desired, be replaced by a dyetoned image, as referred to above, said dye-toned image being either magenta or yellow according to the type of material used.

If a photographic material is used for the production of a negative comprising a support carrying in succession a blue-sensitive, yellow dyed emulsion, a green sensitive'emulsion, colored magenta during processing, and a red sensitive emulsion colored blue-green during processing, exposure being effected" through the support, the record obtained embodies part images which are colored complementarily-gto(the, color aspect of which the image i a'record in each case and such material is obviously-capable of being copied onto a similar copy'materialibut'insuch case the copy material isexposedlthrough the support although the masts record may face either operation. Such printith white light or successively with different ored lights the spectral properties of whicharer-such'that printing is performed correctly in the several layers of the copy material.

' low. Such a master may'be'print'edonto aisimi- If, as shown in Fig,;:2-,. heinegative material includes a support carrying insuccession a red sensitive layer colored yellow, a green sensitive layer and a blue sensitivelayer, exposure being performed from the frontfa record is obtained ,in which the blue of the-original object is rendered as Prussian blue, 'i'. blue-green, the green is recorded as magenta and thered as yellar copy material from thefrontgi. e., emulsion side thereof, either with whitelight-or with colored light in succession. 1

Forms of the material described herein intended for use ascopy; material and for use in the production of a positivelby reversal may include a stripping layer between the emulsion layers and the base t0 enable the layers to betransferredto' ai 'new support, as described in my copending. application Serial No. 384,182, filed March 19, 1941. Alternatively'thelayers could be coated on an opaque or translucent; support such as paper or a layer could be interposed between the support and theemulslon layers which interposed layer is opaqu'elwhite. If exposure has to be made through the support or printing effected in the same manner, such support must be transparent and; alayr may be interposed between the emulsion layers" and the support which is initlallytransparent" and capable of being converted intoanopaque white layerduring proc-- essing as described in myrco-pending application Serial-No, 384,181, filed March 19, 1941. It islto beg-understood that the present invention also includes the copying of a positive natural colorrecord-producedby reversal onto a similar material and the processing of the copied record by: reversal to form duplicated copies.

Further the invention is not restricted to the processing of a multicoated material as three different strata of a single emulsion coat may be sensitised diiferently at different depths and processed as described herein.

I claim:

1. A method of producing a multi-color photographic record on a material including a support and several silver halide emulsion layers coatedthereon of which the layer nearest the support is diffusely dyed with a dye capable of being discharged selectively to form a color image and the other layers are substantially colorless, comprising exposing such material, developing the latent images therein to silver, producing silver ferrocyanide images in said layer, treating the material in-a toning bath containing a ferric salt and auranium salt to form a Prussian blue image in the uppermost layer and a uranium ferrocyanide image in the following layer and, at any stage where the developed silver image in the layer nearest the support remains as silver, producing a color image in said layer by the selective destruction of thedyestuif therein.

2. 4 method of producing aimulti-color photographicrecord on a material including a support arid several silver halide emulsion layers coated thereon of which thelayer'nearest the support is diifuselydyed with a dye capable of being discharged selectively to formacolor image and the other layers are substantially colorless, comprising exposing such material, developing the latent images therein to silver, producing 511 ver ferrocyanideimages in'said layers, treating the material in 'aatonlng bath containing a ferric salt and a uranium salt toform a Prussian blue image in the uppermost layer and a uranium ferrocyanide image in the following layer replacing said latter by a zinc ferrocyanideimage, dye toning the latter image with a dye which mordants to the said image ancLat any stage where the developed image in the layer nearest the support remains as silver, producing'a color image in said layer by the selectivedestruction of the dyestuflf therein. 1 j

3. A method of producing a natural color positive photographic picture on a material including a transparent support a blue sensitive yellow dyed layer of photographic silver halide emulsion coated on said support and green and red sensitive emulsion layers. coated in turn on'said blue sensitive layer, comprising exposing such material through the support, developing the latent images formed in saidilayers; converting the reaidual halide in such layers into a silver ferrotwo further substantially cyanide, toning the latter in a mixed toning bath containinga ferric salt and a uranium salt to form a Prussian blue image in the surface layer and a uranium ferrocyanide image in the following layer and, at any stage where the developed silver image in the layer nearest the support remains as silver, producing a color image in the yellow dyed layer by the selective destruction of the dyestuif therein.

4. A method of producing a master multi-color photographic record from which natural color prints can be produced, employing as exposure material a multi-layer element having a support, a layer thereon which is diffusely dyed with a dyestuif which is capable of being discharged selectively to form a color image and two further layers sensitive to different colors, the outermost layer being blue sensitive, comprising exposing such material from the emulsion side, developing the latent images formed in the layers, bleaching the developed images to silver ferrocyanide, toning the latter in a mixed toning bath containing a ferric salt and sian blue image in the surface layer and a uranium ferrocyanide image in the following layer, and, at any stage where the developed image in the layer nearest the support consists of silver, producing a color image in said layer by theselective destruction of the dyestuif therein at the points unoccupied by the developed silver image.

5. In the production'of a multi-color photographic copy from a multi-color photographic master record, employing as copy material a multi-layer element having a support, a blue-sensitive emulsion layer thereon which is diffusely dyed with a dyestufr which is capable of being discharged selectively to form a color image, and colorless emulsion lay ers sensitive to different colors, the method which comprises printing such copy material from the master record through the support of the copy material; developing the latent images formed in the layers; producing silver ferrocyanide images in said layers; treating the material in a toning bath containing a ferric salt and a uranium salt to form a Prussian blue image in the uppermost layer and a uranium ferrocyanide image in the following layer; and, at any stage where the developed silver image in the layer nearest the support remains as silver, producing a color image in said layer by the selective destruction of the dyestufl. therein.

' ALAN GILBERT TULL.

a uranium salt to form a Prus-

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