Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Silver compound sensitizer containing
Reexamination Certificate
1998-12-10
2001-01-09
Chea, Thorl (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Silver compound sensitizer containing
C430S505000, C430S554000, C430S556000, C430S558000, C430S583000, C430S585000
Reexamination Certificate
active
06171776
ABSTRACT:
This invention relates to a colour photographic silver halide material which is distinguished by elevated sensitivity and improved latent image stability.
Exposed colour photographic silver halide material should provide the most consistent sensitometric results possible when processed, irrespective of whether only a few seconds or many months have elapsed between exposure and processing. This property is known as latent image stability.
Prior art colour photographic silver halide materials having at least one blue-sensitive silver halide emulsion layer containing at least one yellow coupler, at least one green-sensitive silver halide emulsion layer containing at least one magenta coupler and at least one red-sensitive silver halide emulsion layer containing at least one cyan coupler still exhibit unsatisfactory results in this respect.
The object of the invention was accordingly to improve latent imale stability. A further object was to improve the sensitivity of the material, in particular the blue sensitivity of an AcCl based material. This may surprisinlly be achieved in the material described above by a mixture of at least one sensitising dye of the formula (I) and at least one sensitising dye of the formula (II).
The present invention accordingly provides a colour photographic silver halide material of the above-stated type which is characterised in that at least one of the blue-sensitive silver halide emulsions is spectrally sensitised with a sensitising dye mixture of the above-stated type:
in which
R
1
means a substituted or unsubstituted thienyl, substituted or unsubstituted pyrrolyl, substituted or unsubstituted indolyl, substituted or unsubstituted furanyl or substituted or unsubstituted phenyl,
R
2
and R
3
mutually independently mean alkyl, sulfoalkyl, carboxyalkyl, —(CH
2
)
n
CON
&thgr;
—COCH
3
, —(CH
2
)
n
CON
&thgr;
—SO
2
CH
3
, —(CH
2
)
n
SO
2
N
&thgr;
—COCH
3
, or —(CH
2
)
n
SO
2
NHSO
2
CH
3
,
R
4
means H, halogen, benzothienyl or R
1
and
M means a cation or anion required for charge equalisation;
in which
R
5
, R
6
, R
7
, mean H or R
5
and R
6
together or R
6
and R
7
together mean the remaining members of a fused benzo ring and the residual substituent means H and
R
8
and R
9
have the same meaning as R
2
and R
3
R
10
means substituted or unsubstituted thienyl, substituted or unsubstituted benzothienyl, substituted or unsubstituted pyrrolyl, substituted or unsubstituted indolyl, substituted or unsubstituted furanyl or substituted or unsubstitutecl phenyl and
M has the above-stated meaning.
The compounds of the formulae (I) and (II) are preferably used, depending upon the emulsion grain surface area, in a quantity of 0.025 g to 2.5 g per mol of silver halide. Smaller emulsion grains mean a larger grain surface area and the quantity of compounds of the formulae (I) and (II) used must accordingly be increased in order to produce maximum sensitivity.
The mixture ratio of the compounds of the formula (I) to the compounds of the formula (II) (mol/mol) is 1/20 to 20/1. The sensitisation maximum may be shifted in the desired direction by modifying the mixture ratio. The proportion of the longer wave blue sensitiser of the formula (II) should be kept as low as possible in order to improve magenta/yellow colour separation.
Colour photographic silver halide materials having silver halide emulsions consisting of at least 95 mol. % AgCl are preferred, in particular those which contain at most 4 mol. % AgI, preferably less than 0.5 mol. % AgI.
The materials preferably contain at least one yellow coupler of the formula (III)
in which
R
1
, R
2
, R
3
mutually independently mean alkyl or R
2
and R
3
together form a three- to six-membered ring;
R
4
means alkyl, cycloalkyl or aryl;
R
5
m eans halogen, alkyl, alkoxy, aryloxy, aikoxycarbonyl, alkylsulfonyl, alkylcarbamoyl, arylcarbamoyl, alkylsulfamoyl, arylsulfamoyl;
m means 0, 1, 2, 3;
Z
1
means —O—, —NR
6
—;
Z
2
means —NR
7
— or —C(R
8
)R
9
—;
R
6
, R
7
, R
8
and R
9
mutually independently mean hydrogen or a substituent.
The emulsions are ripened, on the one hand, with gold compounds and, on the other, with sulfur and/or selenium compounds.
The emulsions according to the invention may be stabilised in a known manner with acidic NH or SH compounds. The stabilisers are preferably added after post-ripening and are selected in such a manner that they do not displace the sensitising dye or sensitising dyes from the emulsion grains of the silver chloride emulsion and moreover do not impede bleaching of the image silver during processing.
Ripening with sulfur preferaby proceeds with sodium thiosulfate as the ripening agent, but thioureas or isothiocyanates or thiophosphates may also be used as sulfur ripening agents.
Ripening with selenium preferably proceeds with selenoureas which are at least trisubstituted, with heterocyclic selenones, which cannot be deprotonated to yield a selenolate ion, or with phosphane selenides, preferably with triarylphosphane selenides.
Ripening with gold preferably proceeds with gold(III) chloride or a tetrachloroaurate(III) salt, which is reduced to a gold(I) compound during the course of ripening.
Sulfur and/or selenium ripening, on the one hand, and gold ripening, on the other, may proceed simultaneously or in succession.
The emulsions may additionally also be doped with other transitional metal compounds of group VIII and/or of groups IB and IIB of the periodic system, which are added during or after precipitation of the silver chloride in order to establish the desired gradation or a desired development behaviour largely without reciprocity failure. This concerns, for example, salts of rhodium(III) or iridium(IV). The emulsions may also be doped with hexacyanoferrate(II).
The emulsions may additionally also contain palladium(II) or lead(II) compounds, in particular tetrachloropalladates(II), which are intended to improve long term stability.
In order to reduce fog, the emulsions may furthermore contain certain isothiazolone or isoselenazolone compounds, or disulfides or diselenides.
Chemical ripening by sulfur or selenium compounds and gold and spectral sensitisation may be performed separately or in a single stage. The sensitising dyes are preferably added immediately on completion of crystal formation before chemical ripening.
Particularly preferred colour photographic silver halide materials are those which contain pyrazolotriazole magenta couplers of the formula (IV) as the magenta coupler
in which
R means H or a group which is eliminated under chromogenic development conditions,
R
1
means optionally substituted alkyl,
R
2
means R
1
or aryl,
wherein the sum of all the C atoms of residues R
1
and R
2
in a coupler molecule is at least 12.
The colour photographic silver halide material is preferably a print material.
The photographic print materials consist of a support onto which at least one photosensitive silver halide emulsion layer is applied. Thin films and sheets are in particular suitable as supports. A review of support materials and the auxiliary layers applied to the front and reverse sides of which is given in
Research Disclosure
37254, part 1 (1995), page 285.
The colour photographic print materials conventionally contain at least one redsensitive, one green-sensitive and one blue-sensitive silver halide emulsion layer optionally together with interlayers and protective layers.
Depending upon the type of the photographic material, these layers may be differently arranged. This is demonstrated with colour negative paper:
Colour photographic paper, which is usually substantially less photosensitive than a colour photographic film, conventionally has on the support, in the stated sequence, one blue-sensitive, yellow-coupling silver halide emulsion layer, one green-sensitive, magenta-coupling silver halide emulsion layer and one red-sensitive, cyan-coupling silver halide emulsion layer; the yellow filter layer may be omitted.
The substantial constituents of the photographic emulsion layers are the binder, silver halide grains and colour couplers.
Details
Draber Edgar
Ly Cuong
Missfeldt Michael
Teitscheid Heinz-Horst
Agfa N.V.
Chea Thorl
Connolly Dove Lodge & Hutz LLP
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