US2217899A - Light-sensitive multilayer material - Google Patents

Description

Oct. 15, 1940. y P GOLDFINGER 2,217,899

LIGHT-SENSITIVE MULTILAYER MATERIAL Filed NOV. 18, 1938 Fig-1 LLMIIIIIIIIIHJHilllrlrllllrrm- C' lelilllllllllmeIlIllllllllllllH-Jnedf'lfef 1 Emulsmn x Celluloid film Fig,2

:}'Blue .sensitive (ayer yellow layer,- greensensiive Hee( Se'nslfl've [1l/'0r crezmofcz fn,

Inventor Pa ul G'old finger ltorney are of a more uniform thickness.

Patented Oct-.'v15, 1940 UNITED STATES PATENT oFFlca or to Bela Gaspar,

vAplralication November 18, 1938, Serial No. 241,268

- A In Germany November 4, 19..'1

3. Claims. (CL 95-2) The present invention relates to a multilayer light-sensitive material for color photographic purposes in which the exposure of a light-sensitive layer is influenced by the presence. of a screening dye. Thus, for example, in a lm in which a color-sensitive layer is arranged behind a colored colloid layer a part of the light is absorbed by the dye and only the transmitted light rays are capable of exposing the light-sensitive substance.

Exact observations have shown that the. exposure of a light-sensitive layer in a multilayer material is not always sufficiently uniform if the layer is exposed through a. colored filter layer. One object of my invention is, therefore, to improve the uniformity of the exposure in those light-sensitive layers of a multilayer material which are exposed behind a colored layer.

It has been found that the fluctuations in the density of the exposed layer are caused by slight variations in the thickness of the screening layer. It is, therefore, a further object of my invention to provide a` multilayer iight-'sensitive material in which the layers containing 'a screening dye Further objects of my invention will be apparentfrom the following description.

The invention is based on the observation that the fluctuations in thickness are in most cases I more ,or less `regular deviations of the average thickness. The supposition may be taken that these deviations are caused by the oscillations of the support during its passage through the coating device and drying apparatus before the coating has set.

As it is very difficult to res rain the oscillations or vibrations of the support, I have tried to balance the resulting fluctuations in the thickness of the layer by a compensation method. According to the invention the colored colloid layer is formed by two successive coatings of the colored colloid solution which together form two contiguously connected and substantially identical.V

strata of the colored colloid layer. The result of this double coating is a colloid layer of a more' uniform thickness than is obtainable bya single coating. The total thickness of thelayer may be about the same as that of layers hitherto produced in the form of a single coating or thetotal thickness may be'increased by the super-- position of the two -strata of substantially identical colloids.

The invention is illustrated schematically in the attached drawing.' Fig. 1 illustrates a first example of the invention as applied to filter layers made up of two substantially identical coatings. According to a second example illustrated vin Fig. 2, dyed emulsion layers are made up of two substantially identical coatings in accordance with my invention.

In the example illustrated in Fig. 1, a panchromatic emulsion b is coated upon a Celluloid nlm a and on top of the emulsion layer b a red v filter layer c', c" is coated in the following mannerz' 4 'grams of- Rhodamlne B (Schultz .Farbstofltabellen, 7. Auage, 1.'Band, Leipzig 1931,- No. 864) are dissolved in 200 ccs. water and -mixed with 1400 ccs.of 21/2% gelatin solution. 80 ccsf of this colored gelatine solutionare coated upon 1 sq, m. of the panchromatic silver halide layer l5 b to forma coating c'. After the coating c' hasV dried or set, a second coating c" of 80 ccs. of

Athe same red coloredgelatine solution is coated upon the first coating c' to form a coating c". Thereafter, a layer of orthochromatic emulsion d is coated on the red lter layer c', c" and a yellow filter layer e', e" is applied as follows: 8 grams of Tartrazineischultz 1. c. No. 737) are dissolved in 200 ccs. water and mixed with 1400 ccs. gelatine solution of 21/2%. A first coating e of 80 ccs. Aper sq. m. is applied on top of the orthochromatic layer dv and after the setting or drying` of the coating e', a second4 coating e" of 80 ccs. per sq. m. of the ysame yellow gelatine solution is coated upon the first `coating e. ordinary blue sensitive emulsion f is coated over the yellow filter layer e', e". The dyestuffs may be fixed in the gelatine by precipitating agents and the gelatine solutions may contain a hardening agent. It is preferable to add a somewhat higher amount of hardening agent to the portion of colored gelatine solution used for coating the lower stratum of the filter layer.

The light-sensitive 'layers in the above example or more generally light-sensitive layers in any other multilayer material may be coated also by a double .coating process so that the total thickness not only of the filter layers, but also of the light-sensitive silver halide layers is more uniform than in the case' of a layer formed by a single coating. Such an arrangement is illustrated in connection Awith the example of Fig. 42.

AThis uniform thickness is especially important which, in the production dyed throughout the en`- thickness at intensity of not in a layer of plain colloid but in a lightsensitive layer. In the example illustrated in Fig. 2, Chrysophenine G (Schultz 1. c. No. 726) may be used for coloring a light-sensitive silver `halide emulsion which is sensitized to green light. This emulsion is coated in two successive coating operations to form two contiguously connected strata h' and h of the yellow silver halide layer in a multilayer material, the other layers of whichr may be a blue sensitive silver halide layer and a red sensitive layer situated on either side of the green sensitive layer. These blue and red sensitive layers are illustrated as consisting of two coatings each and are marked i', i and y', y, respectively. The support is indicated as a Celluloid film a. The dyestuif, Chrysophenine G, acts as a screening dye during exposure and as an image-forming dye after exposureif the dyestui is locally destroyed at the exposed and developed portions by a dye-destroying agent such as, for instance, an acid thiocarbamide solution. In this casethe more uniform thickness of the colored emulsion layer is useful not only during the exposure .as explained in connection with plain gelatine filter layers, but has the further advantage that all the portions where no dyestui is destroyed in the formation of the dye picture and which represent the darkest points of the nal image show the same color intensity without any noticeable fluctuations caused by uneven coatings.` This applies as well to colored sound records as to picture records.

In the case of a sound film in which the sound record is in the form oi' a black silver record on a uniformly colored background `it is also advantageous that the color of the background does not change its density and also in this case the coloredv layers according to the invention have a remarkable usefulness. The black silver therein a coloring matter and serving as a screening layer for an underlying light-sensitive layer, said screening layer being of substantially uniform thickness and color intensity and comprising two substantially identical coatings directly superposed to each other.

2. A light sensitive multilayer photographic material comprising at least two light-sensitive silver halide emulsion layers sensitized to recorddifferently colored lights, at least one of said layers having incorporated therein a coloring matter and serving as screening layer for the other layer, said screening layer being of substantially uniform thickness and color intensity and comprising two substantially identical coatings directly superposed to each other.

3. A `light-sensitive. multilayer photographic material for color photography comprising at least two light sensitive silver halide emulsion Alayers sensitized to record diierently colored lights, at least one of said layers being arranged for exposure through the other of said layers, said other of said layers being of substantially uniform thickness and transparency and comprising twoidentically sensitized coatings directly superposed to each other and a coloring matter in each of said coatings.

PAUL GOLDFINGER.

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