Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Two or more radiation-sensitive layers containing other than...
Reexamination Certificate
2001-06-08
2003-02-11
Letscher, Geraldine (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Two or more radiation-sensitive layers containing other than...
C430S510000, C430S517000, C430S522000
Reexamination Certificate
active
06518005
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention refers to light sensitive silver halide color photographic elements containing yellow filtering dyes and, more particularly, to light sensitive silver halide color photographic elements where one or more light sensitive layers are protected against blue light exposure with a layer containing a yellow filtering dye.
2. Background of the Art
Light-sensitive silver halide color photographic elements, which make use of subtractive processing to reproduce color, are known to comprise silver halide emulsion layers which are selectively sensitive to blue, to green and to red light and are associated with yellow-dye, magenta-dye and cyan-dye forming couplers, respectively, which (after exposure and reaction with a p-phenylene diamine-type oxidized developer) form their own complementary color. For instance, an acetylanilide-type coupler is used to form a yellow-colored image, a 5-pyrazolone-, pyrazolotriazole-, cyanoacetophenone- or indazolone-type coupler is used to form a magenta-colored image; and a phenol-type coupler, and phenol or naphthol as well, is used to form a cyan-colored image.
Generally, light-sensitive color photographic elements comprise non-diffusing couplers independently incorporated in each of the light sensitive layers of the material (incorporated coupler material). Thus, a light-sensitive color photographic element generally comprises 1) a blue-sensitive silver halide emulsion layer (or layers) which contains a coupler forming a yellow dye (substantially at a wavelength lower than 500 nm); 2) a green-sensitive silver halide emulsion layer (or layers) which contains a coupler forming a magenta dye (substantially at a wavelength from about 500 to 600 nm); and 3) a red-sensitive silver halide emulsion layer (or layers) which contains a coupler forming a cyan dye (substantially at a wavelength higher than 590 nm). The green and red-sensitive silver halide emulsion layers are made sensitive to the green and red regions of the spectrum by properly associating them with a sensitizer, but they keep their own inherent sensitivity to blue light.
The different silver halide emulsion layers sensitive to the different colors are coated onto a support film, such as a cellulose triacetate (CTA), polyethyleneterephthalate (PET) or a polyethylene naphthalate (PEN) film, where the uppermost layer (or layers) is the blue-sensitive emulsion layer (or layers). To prevent blue light from crossing the blue sensitive layer and exposing the lower sensitive layers which in addition to having been sensitized to particular regions of the spectrum, are also inherently sensitive to blue light, thereby causing false coloring, it is a common practice to coat a layer absorbing blue light between the exposure source and the silver halide emulsion layers used to record green and red light. Such a layer, in the art generally called a yellow filter layer, is commonly coated between the blue-sensitive silver halide emulsion layer (or layers) and all other green and red-sensitive silver halide emulsion layers. The yellow filter layer is useful to absorb blue light during exposure and is usually removed during the photographic material processing.
The yellow filter layer commonly used is a gelatin layer containing dispersed yellow colloidal silver, referred to in the art as Carey Lea silver. The yellow colloidal silver absorbs blue light during exposure and is easily decolored during the bleach and fixing steps of the photographic processing. However, yellow colloidal silver has an undesired absorption in the green region of the spectrum and causes a decrease in the effective sensitivity of the underlying silver halide layers in the material. Moreover, yellow silver may cause an undesired higher photographic fog at the boundary line between the yellow filter layer and the silver halide emulsions layers, such that it may be necessary to coat a barrier layer onto both sides of the yellow filter layer. In addition, the production of dispersed yellow colloidal silver is expensive, requires time and experience.
It has been already proposed to use yellow dyes instead of yellow colloidal silver in the yellow filter layers. Yellow dyes alternative to the yellow colloidal silver have been described for instance in U.S. Pat. Nos. 2,538,008; 2,538,009 and 4,420,555; in GB patents 695,873 and 760,739. Even if many of such dyes have satisfactory absorption characteristics, they are not completely useful as regards non-diffusion, cause residual stain after photographic processing, and incubation stains due to their reaction with other components of the photographic material.
Some patents describe a photographic material which contains a yellow filter dye of the pyrole type substituted in the 2-position thereof. For instance, U.S. Pat. No. 5,298,377 and EP 382,225 describe photographic materials among others containing filter dyes having a nucleus of the pyrole type substituted in the 2-position thereof with a vinyl-furanone type nucleus. Such filter dyes are easily decolorized during the photographic processing and do not cause incubation stain, but are not sufficiently resistant to diffusion and cause a sensitivity decrease when they are stored under particular humidity and temperature conditions. U.S. Pat. No. 4,861,700 describes a photographic element containing a yellow filter dye having a tricyanovinyl group in the 2-position and a pyrrole-type group. U.S. Pat. No. 5,776,667 describes a photographic material in the yellow filter layer containing a yellow dye obtained by condensing an isoxazolone nucleus and an aromatic or heteroaromatic aldehyde. The aldehyde nucleus has an oxyethylene group as a substituent. U.S. Pat. No. 4,234,677 describes dye-containing photographic materials: among the many examples of the used dyes, there are described also compounds of the pyrrole type in the 2-position substituted with a vinyl-pyrazolone group.
There are then some patents describing photographic materials which contain pyrrole-type yellow filters having a vinyl group substituted in the 3-position instead of in the 2-position thereof as described in the above-mentioned patents. For example, U.S. Pat. Nos. 5,296,344; 5,449,594; 5,538,836 describe such as filter dye substituted in the 3-position thereof with a vinyl-isoxazolone-type group.
U.S. Pat. Nos. 4,923,788; 6,045,985 and EP 697,758 describe other filter dyes free of the consequences of the colloidal silver and other yellow dyes, such as fog, diffusion and residual stain after processing. In the photographic field there is still the necessity, however, of providing yellow filter dyes satisfying the needs of having a proper absorption, of being quickly and completely decolorized during the photographic processing and of having a good solubility in high-boiling solvents.
SUMMARY OF THE INVENTION
The present invention refers to photographic elements having coated on a support base at least a silver halide emulsion layer sensitized to a radiation different from blue light in addition to the intrinsic or native sensitivity thereof to the blue region or blue radiation, and a yellow filter layer placed between said at least a silver halide emulsion layer and the exposure source, where the filter layer contains a yellow filter dye represented with the formula (1):
wherein R and R
1
each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkylene group, a substituted or unsubstituted heterocyclic group or a substituted or unsubstituted aryl group; R
2
, R
3
and R
4
each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group and R
3
and R
4
may be combined to form a 6-membered ring.
In particular, the present invention relates to multilayer color photographic elements comprising a support having coated thereon in the indicated order starting from the base at least a red-sensitive silver halide emulsion layer, at least a green-sensitive silver halide emulsion
Biavasco Raffaella
Cavalleri Piero
Parodi Stefano
Ferrania S.p.A.
Letscher Geraldine
Mark A. Litman & Assoc. P.A.
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