Claims
- 1. A photosensitive element comprising on a support, at least one silver halide emulsion layer and a non-light sensitive hydrophilic colloid layer wherein the silver halide emulsion layer comprises a chalcogenic compound represented by formula (1): ##STR15## wherein: X represents Se or Te, forming a double bond with its neighboring C-atom,
- Nu represents a nucleophilic acidic group forming a heterolytic bond with its free electron pair,
- L represents a divalent linking group,
- AQB represents the necessary atoms to form a heterocyclic 5- or 6-membered ring, provided that when A is a Nitrogen-atom, B is an atom selected from the group consisting of NR.sup.1, O, S, Se and Te,
- R.sup.1 can represent a hydrogen atom, an alkyl group, an acyl group, an aryl group, an aralkyl group or a heteroaryl group.
- 2. A photosensitive element according to claim 1, wherein the nucleophilic group Nu has a pK.sub.a -value of 2.0 or more.
- 3. A photosensitive element according to claim 1, wherein said compound is a chalcogenic compound satisfying formula (2): ##STR16## wherein: X represents Se or Te, forming a double bond with its neighboring C-atom,
- Nu represents a nucleophilic acidic group forming a heterolytic bond with its free electron pair,
- L represents a divalent linking group,
- Y represents S, O, CR.sup.2 R.sup.3, Se or Te,
- R.sup.2 and R.sup.3 each independently represents a hydrogen atom, an alkyl group, an aryl group, an aralkyl group or a heteroaryl group, or R.sup.2 and R.sup.3 each independently represents the atoms which together with R.sup.4 or R.sup.5 are necessary to form a ring structure, or R.sup.2 and R.sup.3 each independently represents a hydrogen atom, an alkyl group, an aryl group, an aralkyl group or a heteroaryl group which combine to form a ring structure,
- R.sup.4 and R.sup.5 each independently represents a hydrogen atom, an alkyl group, an aryl group, an aralkyl group or a heteroaryl group, or R.sup.4 and R.sup.5 together represent the atoms necessary to form a ring structure.
- 4. A photosensitive element according to claim 3, wherein the nucleophilic group Nu has a pK.sub.a -value of 2.0 or more.
- 5. A photosensitive element of claim 1, wherein the said compound is a chalcogenic compound satisfying formula (3): ##STR17## wherein: Nu represents a nucleophilic acidic group forming a heterolytic bond with its free electron pair,
- L represents a divalent linking group,
- R.sup.6 represents a hydrogen atom, an alkyl group, an aryl group, an aralkyl group or a heteroaryl group, or one or R.sup.6 substituents together represent the atoms necessary to form a ring structure,
- n equals 0, 1, 2, 3 or 4.
- 6. A photosensitive element according to claim 5, wherein the nucleophilic group Nu has a pK.sub.a -value of 2.0 or more.
- 7. A photosensitive element according to claim 1, wherein at least one silver halide emulsion is chemically sensitized with a chalcogenic compound satisfying formula (1) in an amount of 10.sup.-8 to 10.sup.-3 mole based on one mole of silver halide.
- 8. A method for chemically sensitizing a silver halide emulsion characterized by the step of adding a sulphur sensitizer, a gold sensitizer or both a sulphur and a gold sensitizer, together with a chalcogenic compound as defined in claim 1.
- 9. A method according to claim 8, characterized by the step of adding a silver halide solvent to the chalcogenic compound.
- 10. A method according to claim 8, characterized by the step of adding a spectral sensitizer to the chalcogenic compound.
- 11. A method according to claim 8, wherein said step of chemically sensitizing a silver halide emulsion is performed in following conditions: a pAg-value in the range of from 6 to 11, a pH-value in the range of from 3 to 10 and a temperature in the range of 40 up to 95.degree. C.
- 12. A method according to claim 9, wherein the silver halide solvent is a thiocyanate salt.
- 13. A method according to claim 9, wherein the silver halide solvent is present in an amount of 10.sup.-6 to 10.sup.-1 mole per mole of silver halide.
- 14. A method according to claim 10, wherein the spectral sensitizer is a cyanine dye containing a benzoxazole, a benzthiazole or a benzimidazole nucleus.
Priority Claims (1)
Number |
Date |
Country |
Kind |
97202395 |
Aug 1997 |
EPX |
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Parent Case Info
This is a continuation in part application of Ser. No. 09/115,627, filed Jul. 14, 1998, abandoned.
Foreign Referenced Citations (1)
Number |
Date |
Country |
19635098 |
Mar 1998 |
DEX |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
115627 |
Jul 1998 |
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