Thiosulfonate-sulfinate stabilizers for photosensitive emulsions

A negative silver halide photographic emulsion comprising (1) crystals of a compound selected from the group consisting of silver chloride and silver bromochloride, and (2) a composition comprising, in amounts effective for reducing photographic speed change upon storage, a compound of formula I:

• Z.sup.1 --X.sup.1 O.sub.2 --M.sup.1 (I)
• and a compound of formula II.
• Z.sup.2 --X.sup.2 O--M.sup.2 (II)
• wherein X.sup.1 is sulfur and X.sup.2 is selected from the group consisting of sulfur and selenium, M.sup.1 and M.sup.2 are independently selected from the group consisting of an alkali metal ion and ##STR5## wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are independently selected from the group consisting of hydrogen and an alkyl of 1-3 carbon atoms, and Z.sup.1 and Z.sup.2 are independently selected from the group consisting of an unsubstituted or substituted alkyl of 1 to 18 carbon atoms, an unsubstituted or substituted aryl group having 6 to 10 carbon atoms, an unsubstituted or substituted 5-membered or 6-membered heterocyclic group having one or two heteroatoms, and L, wherein L is a divalent linking group, wherein the compound of formula I is present in about 0.01 mmoles to about 10 mmoles per mole silver, and the compound of formula II is present at about 0.5 moles to about 20 moles per mole of the compound of formula I, provided that, if Z.sup.1 is L, the compound of formula I is a polymer and, if Z.sup.2 is L, the compound of formula II is a polymer, and provided further that, if the compound of formula I is a polymer, each polymeric unit comprising the moiety of formula --X.sup.1 O.sub.2 S-- is counted as a molecule of the compound of formula I and, if the compound of formula II is a polymer, each polymeric unit comprising the moiety of formula --X.sup.2 O.sub.2 -- is counted as a molecule of the compound of formula II.

A method for reducing speed change on aging in a photographic material, which comprises a negative photographic emulsion coated on a paper support, said emulsion comprising crystals of a compound selected from the group consisting of silver chloride and, silver bromochloride, said method comprising treating said emulsion with an amount effective for reducing fog growth upon storage of said photographic material of a compound of formula I:

• Z.sup.1 --X.sup.1 O.sub.2 --M.sup.1 (I)
• and a compound of formula II:
• Z.sup.2 --X.sup.2 O--M.sup.2 (II)
• wherein X.sup.1 is sulfur and X.sup.2 is selected from the group consisting of sulfur and selenium, M.sup.1 and M.sup.2 are independently selected from the group consisting of an alkali metal ion and ##STR7## wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are independently selected from the group consisting of hydrogen and an alkyl of 1-3 carbon atoms, and Z.sup.1 and Z.sup.2 are independently selected from the group consisting of an unsubstituted or substituted alkyl of 1 to 18 carbon atoms, an unsubstituted or substituted aryl group having 6 to 10 carbon atoms, an unsubstituted or substituted 5-membered or 6-membered heterocyclic group having one or two heteroatoms, and L, wherein L is a divalent linking group, provided that, if Z.sup.1 is L, the compound of formula I is a polymer and, if Z.sup.2 is L, the compound of formula II is a polymer