Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Silver compound sensitizer containing
Reexamination Certificate
2000-09-27
2002-09-17
Chea, Thorl (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Silver compound sensitizer containing
C430S556000, C430S567000, C430S583000
Reexamination Certificate
active
06451521
ABSTRACT:
The invention relates to a photosensitive color photographic silver halide material which contains, in at least one layer, at least one spectrally sensitized silver halide emulsion containing at least 95 mol-% AgCl, preferably at least 98.5 mol-% AgCl, and has improved low-density stability in the unexposed state (lower storage fog).
It is known that AgCl emulsions frequently have a high fog which is produced by reduction of silver ions to metallic silver during the precipitation. To avoid this, oxidizing agents such as Hg salts, permanganates, peroxides and persulfates are added. Said oxidizing agents frequently have a negative effect on the photographic properties, particularly on the sensitivity.
It is furthermore known that silver halide emulsions having a high chloride content exhibit a density increase in the region of the threshold gradation during storage, regardless of the spectral sensitivity. The heat stability of spectrally sensitized, in particular blue-sensitized, silver chloride emulsions is also unsatisfactory in the region of low densities.
The object of the invention was to avoid these disadvantageous effects.
It was found that the addition of salts of indium, of yttrium, of lanthanum and of the rare earths cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium, referred to below as earth-metal salts, to one of the solutions of the emulsion mixture for producing a photosensitive silver halide emulsion having a high chloride content results in an unexpected improvement in the fog in the fresh state and in the stability of the photographic properties during storage in the unexposed state, whereas the low densities (emulsion fog and threshold gradation) are essentially kept stable at elevated temperature.
Disadvantageous alterations in the photographic properties of the emulsions are not associated with the addition, according to the invention, of the earth-metal salts.
The addition of rare-earth-metal salts to silver halide emulsions has hitherto been disclosed (U.S. Pat. No. 3,178,289) only in connection with the improvement of the point quality in photographic emulsions containing at least 7.5 mol-% AgBr which are subjected to a lith development.
The doping of a silver halide emulsion whose grains have at least 4 shells, of which at least one shell, but not all the shells, are doped with indium or lanthanum and the like or another shell, but not all the shells are doped with iodine, results, in black/white materials, in a stabilization of the photographic properties (DE 37 23 419).
The invention consequently relates to a color photographic silver halide material having a base and at least one photosensitive silver halide emulsion layer which is applied thereto and whose silver halide comprises at least 95 mol-%, preferably at least of 98.5%, of AgCl, characterized in that the silver halide emulsion contains 10
−7
to 10
−3
mol of at least one metal selected from indium, yttrium, lanthanum and the lanthanides per mol of silver halide.
The silver halide crystals are preferably prismatic, cubic or tabular. They are, in particular, blue-sensitized.
The silver halide crystals according to the invention are prepared in that the silver halide precipitation is performed in the presence of soluble salts of metals of the lanthanide group, of indium or of yttrium or are redissolved with fine-grain silver halide crystals doped with the said metals.
According to the invention, the soluble simple or complex salts, including the halides, sulfates and nitrates of the bivalent, trivalent or tetravalent metals, in particular, are used as soluble earth metal salts.
The amount of halide of the silver halides required to make up to 100 mol-% is preferably AgBr.
The color photographic silver halide material is, in particular, a print material.
Preferably the following metal salts are used: Pr, Eu, Ce and In.
The emulsions according to the invention are ripened in the normal manner, stabilized, chemically and spectrally sensitized and mixed with the usual emulsion additives.
Suitable as ripening agents are, for example, thiosulfate, thiourea, open-chain and cyclic thioamides, thiocarbamates, xanthogenates, selenoureas, open-chain or cyclic selenoamides, heterocyclic, in particular heteroaromatic selenols, phosphane selenides, selenium sulfates, selenium phosphates, selenium phosphonates, selenium phosphoramides.
Preferred blue-sensitizers correspond to the formula (I)
wherein
R
11
to R
13
and R
16
to R
18
represent H, alkyl, alkoxy, halogen, 2-thienyl, 3-thienyl, 1-pyrrolyl, 2-pyrrolyl, phenyl, 1-indolyl, 2-furanyl, 3-furanyl or carbazolyl,
R
14
and R
15
represent alkyl, sulfoalkyl, carboxyalkyl, —(CH
2
)
n
SO
2
N
&thgr;
—COR
19
, —(CH
2
)
n
SO
2
N
&thgr;
SO
2
R
19
, —(CH
2
)
n
CON
&thgr;
SO
2
R
19
or —(CH
2
)
n
CON
&thgr;
COR
19
,
X
11
and X
12
represent O, S, Se, or NR
20
,
M represents a counterion,
n represents an integer from 2 to 4 and
R
19
and R
20
represent C
1
-C
4
-alkyl or
R
11
and R
12
or R
12
and R
13
, R
16
and R
17
or R
17
and R
18
represent the remaining members of a fused benzene or naphthalene ring.
Particularly preferred blue-sensitizers correspond to the formula (II)
wherein
R
21
and R
23
represent hydrogen
R
22
represents halogen, in particular chlorine or fluorine, 2-thienyl, 3-thienyl, 1-pyrrolyl, 2-furanyl, 1-indolyl or phenyl or
R
21
and R
22
taken together or R
22
and R
23
taken together represent the remaining members of a fused benzene or naphthalene ring,
R
24
represents hydrogen,
R
25
represents halogen, in particular chlorine or fluorine, phenyl, 2-thienyl, 3-thienyl, 1-pyrrolyl, 2-furanyl, 1-indolyl or
R
24
and R
25
taken together represent the remaining members of a fused benzene or naphthalene ring,
X
21
represents S or O,
M represents a counterion, in particular triethylamrnonium, and
l and m represent an integer from 2 to 4.
The blue-sensitized silver halide emulsion contains, in particular, a stabilizer selected from the 1-phenyl-5-mercaptotetrazoles.
The blue-sensitized silver halide emulsion layer normally contains at least one yellow-coupler, preferably a biequivalent yellow-coupler.
Preferred as two-equivalent yellow-couplers are acetanilides, in particular pivaloyl-acetanilides and malonanilides whose labile groups are linked via O or N with the coupler molecule and which are substituted in the ortho-position of the anilide part by chlorine, alkoxy or aryloxy.
Particularly preferred two-equivalent yellow couplers correspond to the formula (III):
wherein
R
31
represents alkyl, preferably containing 1 to 4 C atoms, in particular methyl,
R
32
represents alkyl, preferably containing 1 to 4 C atoms, in particular methyl,
R
33
represents a hydrogen atom or alkyl, preferably containing 1 to 4 C atoms, in particular methyl, or
R
32
and R
33
taken together represent the remaining members of a cyclopropyl radical,
R
34
represents chlorine or alkoxy,
R
35
represents —NHCO—R
37
, —SO
2
NH—R
37
, —NHSO
2
—R
37
, —COOR
37
, Cl, Br or alkoxy,
R
36
represents a hydrogen or chlorine atom,
R
37
represents a substituent, in particular a ballast group and
Q represents the remaining members of a substituted imidazole, imidazolidinedione, oxazolidinedione or triazolidinedione ring,
wherein the alkyl groups may be further substituted.
Suitable yellow couplers are
Suitable compounds of the formula (II) are the following, in which 1 and m=3 and triethylammonium is counterion:
X
3
R
21
R
22
R
23
R
24
R
25
II-1
S
H
2-thienyl
H
H
Cl
II-2
S
H
3-thienyl
H
H
Cl
II-3
S
H
1-pyrrolyl
H
H
Cl
II-4
S
H
2-furyl
H
H
F
II-5
S
H
1-indolyl
H
H
Cl
II-6
S
H
benzo
H
Cl
II-7
S
H
Cl
H
H
Cl
II-8
S
H
1,2-naphtho
H
Cl
II-9
O
H
2,3-naphtho
H
Cl
II-10
O
1,2-naphtho
H
benzo
II-11
S
H
Cl
H
H
phenyl
II-12
S
H
benzo
benzo
II-13
O
H
benzo
1,2-naphtho
II-14
S
H
2-thienyl
H
H
2-thienyl
II-15
S
H
3-thienyl
H
H
3-thienyl
II-16
S
H
1-pyrrolyl
H
H
1-pyrrolyl
II-17
S
H
1-indolyl
H
H
1-indolyl
II-18
S
H
Cl
H
benzo
Examples of color photographic silver
Berthaller Peter
Borst Hans-Ulrich
Feigl Matthias
Agfa-Gevaert
Chea Thorl
Connolly Bove & Lodge & Hutz LLP
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