Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Two or more radiation-sensitive layers containing other than...
Reexamination Certificate
2002-10-28
2004-08-31
Schilling, Richard L. (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Two or more radiation-sensitive layers containing other than...
C430S214000, C430S505000
Reexamination Certificate
active
06783922
ABSTRACT:
FIELD OF THE INVENTION
The present invention is directed to the field of photographic materials containing scavenger molecules that are applied in the intermediate interlayers between the photographic sensitive emulsion layers.
BACKGROUND OF THE INVENTION
Colour photographic elements are conventionally formed with blue, green and red recording layers coated on a film support. The blue, green and red recording layers contain radiation-sensitive silver halide emulsions that form a latent image if irradiated by blue, green and red light, respectively. The blue recording layer contains a yellow dye image-forming coupler, the green recording layer contains a magenta dye image-forming coupler and the red recording layer contains a cyan dye image-forming coupler. After the photographic element is exposed by an image, it is processed in a colour developer, which contains a colour developing agent that is oxidised by the selective reduction of the silver in the silver halide grains with the formation of the silver latent image. The oxidised colour developing agent then reacts with the dye image-forming coupler in the vicinity of the developed grains to produce an image dye. Yellow (absorbs blue light), magenta (absorbs green light) and cyan (absorbs red light) image dyes are formed in the blue, green and red recording layers respectively. Subsequently the photographic element is bleached (i.e. developed silver is converted back to silver halide) in order to eliminate the neutral density attributable to developed silver and then fixed (i.e. silver halide is removed) in order to provide stability during subsequent handling at room light conditions.
When processing is conducted as noted above, negative dye images are produced. To produce a viewable positive dye image and hence to produce a visual approximation of the hues of the subject photographed, white light is typically passed through the colour negative image to expose a second photographic element also having blue, green and red recording layers as described above, usually coated on a white reflective paper support. The second element is commonly referred to as a colour print element and the process of exposing the colour print element through the image bearing colour negative element is commonly referred to as printing. Processing the colour print element at the same way as described above for the negative film support produces a viewable positive image that approximates that of the subject originally photographed.
Both photographic elements, the colour negative film and the colour positive paper supports, contain radiation-sensitive silver halide emulsions in the blue, green and red recording layers. Image dyes are formed by the reaction of the oxidised developer molecules with the dye image-forming coupler. The oxidised developer molecules can migrate easily from one colour recording layer into another colour recording layer, which will cause imbalances in colour reproduction because a wrong colour dye is generated in an other recording layer. This phenomenon is called colour mix or colour contamination. In order to prevent this diffusion travelling of the oxidised developers the photographic elements contain scavenger molecules which are able to neutralise the oxidised molecules and preventing that a colour coupler forms the wrong colour dye in an other recording layer. Sometimes a certain (limited) amount of colour mix may be desirable for a better appearance of the image. This makes the design of the interlayer a complicated matter. The scavenger molecules are conventionally present in the intermediate interlayers between the different colour recording layers of the colour negative film but also in the same way at the colour positive paper support. The scavenger molecules are dissolved in an oil-in-water emulsion and as such integrated in the interlayers. An important disadvantage of the scavenger oil-water emulsion is that by increasing the quantity of oil-water emulsion the sharpness quality is negatively influenced due to increased scattering chances.
It has been described in EP-A 576911 to couple functional carboxylic acid groups of R—COOH compounds to the amine groups of gelatine
The coupling of scavenger molecules to a polymer compound has already been described in JP-4062548, said polymers being applied in the interlayers of photographic products. The use of water-soluble polymers (proteins, polyvinyl alcohol (PVA), polyvinyl glycol (PVG)) coupled to different scavenger molecules is disclosed. The scavenger modified polymer molecules in the interlayers result in reduced colour contamination effects while also the photographic sensitivity after ageing is improved versus the conventional recipes in which the scavenger molecules are dissolved in the oil-water emulsion of the interlayers. The amount of scavenger modified polymer per square meter is disclosed over a very broad range from 1 mg to 20 g per square meter.
SUMMARY OF THE INVENTION
The present invention is based upon the surprising insight that the use of a specific concentration range of scavenger moieties in a scavenger modified polymers in combination with specific values for the thickness of the interlayer layer, results in a highly effective scavenging function against the migrated oxidised developer molecules whereas we found that the concentration of scavenger should be limited to prevent reduction of the maximum density D
max
in the colour recording layer.
The specific combinations of layer thicknesses and scavenger concentrations, which combinations are used in accordance with the present invention are conveniently expressed by a single design parameter. In this interlayer design parameter, the dry thickness of the interlayer (called d) is combined with the concentration of scavenger moieties in the interlayer (called [scavenger]). It was found that the design parameter {[scavenger moiety].d
2
} predicts the scavenging extend of the migrated oxidised developer molecules. Using this new interlayer design parameter it has thus become possible to specify a range of specific thicknesses in combination with a specified concentration range of scavenger moieties in the interlayer for which acceptable colour contamination happens in the colour recording layers as well as no reduction of the maximum density D
max
, while the dye fading and the sharpness quality of each colour recording layer improve.
Accordingly the invention comprises in its broadest scope a photographic material, comprising a photographic support and color sensitive recording layers on top of said support, said recording layers being separated from each other by interlayers, wherein the interlayers are characterised by the color mix predictive product function {[scavenger moiety].d
2
}>2.0*10
−15
mmol m
2
/g. In preferred embodiments the value of the product function is larger than 5.0*10
−15
mmol m
2
/g, most preferably larger than 10.0*10
−15
mmol m
2
/g.
The present invention is in a preferred embodiment directed to a photographic material containing scavenger modified polymers comprising scavenger moieties linked to a water soluble polymer, which polymers are applied in the interlayers, so that a concentration of scavenger moieties in the scavenger modified polymer that is lower than 0.5 mmol/g total polymer in the interlayer. In preferred embodiments these values are lower than 0.30, most preferably lower than 0.15 mmol/g polymer.
One of the additional advantages of the present invention is, that photographic material can be provided having one or more interlayers, with a thickness and scavenger concentration that is exactly tuned to meet the required specifications with respect to D
max
and color mix. This makes it possible to provide materials having interlayer thicknesses that are smaller than those of conventional materials.
In the present invention the reactive group (carboxylic acid, amine) of the scavenger compound is linked with the reactive groups (amine, carboxylic acid) of the water-soluble polymer, pre
Bouwstra Jan Bastiaan
Kluijtmans Sebastianus Gerardus J. M.
Toda Yuzo
Fuji Photo Film B.V.
Schilling Richard L.
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