1. A radiation-sensitive composition, comprising:
a radical initiator;
a radical polymerizable component; and
a radiation absorption compound,
wherein the radiation-sensitive composition shows two or more peaks of a radical generation amount in a radical generation amount-versus-time curve after exposure to image forming radiation.
2. The radiation-sensitive composition according to claim 1,
wherein a peak interval between a peak of the radical generation amount which is initially generated with respect to time after the exposure to the image forming radiation and at least one of peaks of the radical generation amount which are generated subsequent to the initially generated peak, among the peaks of the radical generation amount, is 40 ms or greater.
3. The radiation-sensitive composition according to claim 1 or 2,
wherein at least one of peaks of the radical generation amount which are generated subsequent to the initially generated peak with respect to the time after exposure to the image forming radiation, among the peaks of the radical generation amount, is a peak derived from a decomposition product of the radiation absorption compound.
4. The radiation-sensitive composition according to any one of claims 1 to 3,
wherein the radical initiator comprises an electron-donating radical initiator, and the radiation absorption compound comprises a compound which is decomposable to generate a radical due to exposure to the image forming radiation.
5. The radiation-sensitive composition according to any one of claims 1 to 3,
wherein the radical initiator comprises an electron-donating radical initiator and an electron-accepting radical initiator.
6. The radiation-sensitive composition according to claim 5,

wherein a difference between a highest occupied molecular orbital of the radiation absorption compound and a highest occupied molecular orbital of the electron-donating radical initiator is 0.61 eV or greater.
7. The radiation-sensitive composition according to claim 5 or 6,
wherein a difference between a lowest unoccupied molecular orbital of the electron-accepting radical initiator and a lowest unoccupied molecular orbital of the radiation absorption compound is 0.90 eV or less.
8. A planographic printing plate precursor, comprising:
a support; and
an image recording layer which comprises a radical initiator, a radical polymerizable component, and a radiation absorption compound, and wherein the image recording layer shows two or more peaks of a radical generation amount in a radical generation amount-versus-time curve after exposure to image forming radiation.
9. The planographic printing plate precursor according to claim 8, further comprising:
a protective layer on the image recording layer.
10. The planographic printing plate precursor according to claim 8 or 9,
wherein a peak interval between a peak of the radical generation amount which is initially generated with respect to time after the exposure to the image forming radiation and at least one of peaks of the radical generation amount which are generated subsequent to the initially generated peak, among the peaks of the radical generation amount, is 40 ms or greater.
11. The planographic printing plate precursor according to any one of claims 8 to 10,
wherein at least one of peaks of the radical generation amount which are generated subsequent to the initially generated peak with respect to the time after exposure to the image forming radiation, among the peaks of the radical generation amount, is a peak derived from a decomposition product of the radiation absorption compound.
12. The planographic printing plate precursor according to any one of claims 8 to 11,

wherein the radical initiator comprises an electron-donating radical initiator, and the radiation absorption compound comprises a compound which is decomposable to generate a radical due to exposure to the image forming radiation.
13. The planographic printing plate precursor according to any one of claims 8 to 11,
wherein the radical initiator comprises an electron-donating radical initiator and an electron-accepting radical initiator.
14. The planographic printing plate precursor according to claim 13,
wherein a difference between a highest occupied molecular orbital of the electron-donating radical initiator and a highest occupied molecular orbital of the radiation absorption compound is 0.61 eV or greater.
15. The planographic printing plate precursor according to claim 13 or 14,
wherein a difference between a lowest unoccupied molecular orbital of the electron-accepting radical initiator and a lowest unoccupied molecular orbital of the radiation absorption compound is 0.90 eV or less.
16. The planographic printing plate precursor according to any one of claims 8 to 15, further
comprising:
an interlayer between the support and the image recording layer.
17. The planographic printing plate precursor according to any one of claims 8 to 16,
wherein the radiation absorption compound comprises an infrared absorption compound.
18. The planographic printing plate precursor according to any one of claims 8 to 17,
wherein the image recording layer is removable by any one or both of dampening water and printing ink.
19. A plate-making method for a planographic printing plate, the method comprising:
subjecting the planographic printing plate precursor according to any one of claims 8

to 17 to image-wise light exposure; and
removing a non-image area of an image recording layer from the exposed planographic printing plate precursor in the presence of a developer having a pH of 2 to 14.
20. A plate-making method for a planographic printing plate, the method comprising:
subjecting the planographic printing plate precursor according to any one of claims 8
to 18 to image-wise light exposure; and
supplying any one or both of printing ink and dampening water on a printing press to
remove a non-image area of an image recording layer.