Image formation method

A method of preparing a photothermographic material and subsequently forming an image thereon, comprising:

• applying at least one image-forming layer comprising a coating solution containing 50 weight % or more of an organic solvent based upon the total weight of solvent in the coating solution and at least one hydrophobic transparent binder,
• drying said coated solution to obtain a photothermographic material having an image-forming layer and a back layer, wherein at least one layer constituting the photothermographic material contains at least one high contrast agent selected from the group consisting of hydrazine derivatives, quaternary ammonium compounds, quatemary phosphonium compounds and at least one high contrast agent represented by the following formula (e):
• wherein Re1 represents an electron-withdrawing group, Re2 represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group, a halogen atom, an acyl group, a thioacyl group, an oxalyl group, an oxyoxalyl group, a thiooxalyl group, an oxamoyl group, an oxycarbonyl group, an —S-carbonyl group, a carbamoyl group, a thiocarbamoyl group, a sulfonyl group, a sulfinyl group, an oxysulfonyl group, a thiosulfonyl group, a sulfamoyl group, an oxysulfinyl group, a thiosulfinyl group, a sulfinamoyl group, a phosphoyl group, a nitro group, an imino group, an N-carbonylimino group, an N-sulfonylimino group, a dicyanoethylene group, an ammonium group, a sulfonium group, a phosphonium group, a pyrylium group or an immonium group, Re3 represents a halogen atom, a hydroxy group or a salt thereof, an alkoxy group, an aryloxy group, a heterocyclyloxy group, an acyloxy group, an alkenyloxy group, an alkynyloxy group, an alkoxycarbonyloxy group, an aminocarbonyloxy group, a mercapto group or a salt thereof, an alkylthio group, an arylthio group, a heterocyclylthio group, an alkenylthio group, an alkynylthio group, an acylthio group, an alkoxycarbonylthio group, an aminocarbonylthio group, an amino group, an alkylamino group, an arylamino group, an acylamino group, an oxycarbonylamino group, a ureido group or a sulfonamido group, and the trans-configuration between Re1 and Re3 is also included in the scope of the formula (e),
• exposing a photothermographic material with a light having a wavelength of 700-850 nm, and
• subjecting the exposed photothermographic material to development in a heat development apparatus provided with a preheating section, a heat development section and a gradual cooling section, wherein the heat development section is provided with heating members on the image-forming layer side and the back layer side and transportation rollers only on the image-forming layer side with respect to the photothermographic material to be transported in the apparatus.