WE CLAIM:
1. A curable composition for a lithographic printing plate comprising:
a salt compound having
a) an organic anion in which, in Hansen solubility parameter, 5d is 16 or more, 5p is 16 or more and 32 or less, and 5H is 60% or less of 5p; and
b) a counter cation.
2. The curable composition for a lithographic printing plate according to claim 1,
wherein the organic anion is an organic anion having an aromatic ring or a hetero ring in a molecule.
3. The curable composition for a lithographic printing plate according to claim 1,
wherein the organic anion is (A) an organic anion having a sulfonamide anion structure that bonds to a ring or a sulfonimide anion structure that bonds to a ring.
4. The curable composition for a lithographic printing plate according to claim 2,
wherein the organic anion is an organic anion represented by Formula (V),

in Formula (V), Cy1 and Cy2 may be identical to or different from each other and each represent a ring structure formed with all of a boron atom, an oxygen atom, and Y, Y’s each independently represent -O- or -NR5-, and R5 represents a hydrogen atom, an alkyl carbonyl group, an aryl carbonyl group, an alkyl sulfonyl group, an aryl sulfonyl group, an alkoxycarbonyl group, an aryl group, or a heteroaryl group; and
the ring structure represented by Cy1 is fused with an aromatic ring having at least one group selected from the group consisting of an alkylamide group, an alkenylamide group, an arylamide group, an alkylurea group, an arylurea group, a group having a sulfonamide structure, and a group having a sulfonimide structure, and the ring structure represented by Cy2 is fused with an aromatic ring having at least one group selected from the group consisting of an alkylamide group, an alkenylamide group, an arylamide group, an alkylurea group, an arylurea group, a group having a sulfonamide structure, and a group having a

sulfonimide structure.
5. The curable composition for a lithographic printing plate according to claim 4,
wherein the organic anion is an organic anion represented by Formula (VI),

in Formula (VI), R7 to R14 may be identical to or different from each other and each independently represent a hydrogen atom, an alkyl group, an alkylamide group, an alkenylamide group, an arylamide group, an alkylurea group, an arylurea group, a group having a sulfonamide structure, or a group having a sulfonimide structure;
at least one of R7, R8, R9, or R10 represents an alkylamide group, an alkenylamide group, an arylamide group, an alkylurea group, an arylurea group, a group having a sulfonamide structure, or a group having a sulfonimide structure, and
at least one of R11, R12, R13, or R14 represents an alkylamide group, an alkenylamide group, an arylamide group, an alkylurea group, an arylurea group, a group having a sulfonamide structure, or a group having a sulfonimide structure.
6. A curable composition for a lithographic printing plate comprising:
a salt compound having
(A) an organic anion having
a sulfonamide anion structure that bonds to a ring or a sulfonimide anion structure that bonds to a ring, and
(B) a counter cation.
7. The curable composition for a lithographic printing plate according to claim 6,
wherein the organic anion is represented by General Formula (I),

in General Formula (I), Cy represents an aryl group, a heteroaryl group, or an alicyclic group that may have an unsaturated bond; and
X represents an alkyl group, an aryl group, a heteroaryl group, SO2Ra, SORb, CORc, PO3Rd, PO(Re)(Rf), or H, Ra, Rb, Rc, Rd, Re, and Rf represent a group selected from the group consisting of an alkyl group, an alkoxy group, an aryl group, a heteroaryl group, and H, and Ra, Rb, Rc, Rd, Re, or Rf may bond to Cy to form a ring.
8. The curable composition for a lithographic printing plate according to claim 7,
wherein the organic anion is represented by General Formula (II),

in General Formula (II), Cy represents an aryl group, a heteroaryl group, or an alicyclic group that may have an unsaturated bond; and
Ra represents a group selected from the group consisting of an alkyl group, an alkoxy group, an aryl group, a heteroaryl group, and H, and Ra may bond to Cy to form a ring.
9. The curable composition for a lithographic printing plate according to claim 8,
wherein the organic anion is represented by General Formula (III) or (IV),

in General Formula (III), R1 to R10 each independently represent a hydrogen atom or a monovalent substituent, and
in General Formula (IV), R11 to R14 each independently represent a hydrogen atom or a monovalent substituent.
10. The curable composition for a lithographic printing plate according to any one of claims
1 to 9,
wherein the counter cation is a diaryliodonium cation or a triarylsulfonium cation.
11. The curable composition for a lithographic printing plate according to any one of claims
1 to 9,
wherein the counter cation is a counter cation in a cyanine-based colorant.
12. The curable composition for a lithographic printing plate according to any one of claims
1 to 9,
wherein the counter cation is an alkali metal ion, an alkali earth metal ion, or an organic cation having a positive charge present on a nitrogen atom.
13. The curable composition for a lithographic printing plate according to any one of claims
1 to 10 and 12, further comprising:
an infrared absorber.
14. The curable composition for a lithographic printing plate according to claim 13,
wherein the infrared absorber is a cyanine-based colorant.
15. The curable composition for a lithographic printing plate according to any one of claims

1 to 14, further comprising:
a polymerizable compound.
16. The curable composition for a lithographic printing plate according to any one of claims
1 to 15, further comprising:
an acid color-developing agent.
17. The curable composition for a lithographic printing plate according to any one of claims
1 to 16, further comprising:
a polymer particle.
18. The curable composition for a lithographic printing plate according to any one of claims
1 to 17, further comprising:
a binder polymer.
19. A lithographic printing plate precursor comprising:
an image-recording layer containing the curable composition for a lithographic printing plate according to any one of claims 1 to 18 on a support.
20. The lithographic printing plate precursor according to claim 19, further comprising:
a protective layer on the image-recording layer.
21. A method for producing a lithographic printing plate comprising:
a step of image-exposing the lithographic printing plate precursor according to claim 19 or 20; and
a step of removing a non-exposed portion of the image-recording layer on a printer using at least one selected from the group consisting of printing ink and dampening water.
22. A method for producing a lithographic printing plate comprising:
a step of image-exposing the lithographic printing plate precursor according to claim 19 or 20; and
a step of removing a non-exposed portion of the image-recording layer using a developer having pH of 2 to 11.

23. A compound, comprising:
an organic anion which is represented by General Formula (III) or (IV); and a counter cation which is a diaryliodonium cation or a triarylsulfonium cation,

in General Formula (III), R1 to R10 each independently represent a hydrogen atom or a monovalent substituent, and
in General Formula (IV), R11 to R14 each independently represent a hydrogen atom or a monovalent substituent.
24. A compound, comprising:
an organic anion which is represented by General Formula (III) or (IV); and a counter cation which is a counter cation in a cyanine colorant,

in General Formula (III), R1 to R10 each independently represent a hydrogen atom or a monovalent substituent, and
in General Formula (IV), R11 to R14 each independently represent a hydrogen atom or a monovalent substituent.