PURPOSE: To allow development to prevent unevenness by processing a recording material, which is formed with latent images to be color developed by pressurizing, heating, transferring or the combination thereof on a base, under pressurization using gas or liquid or under heating, thereby substantially developing the material.
CONSTITUTION: The recording material, which is formed with latent images to be color developed by pressurizing, heating, transferring or the combination thereof on the base, is processed under the pressurization using the gas or liquid or under the heating, by which the material is substantially developed. One or more kinds of carbon dioxide, air, nitrogen, hydrocarbon halide, for example, paraffin fluoride, fluorocarbon deriv., and olefin, etc., are used as the gas of this case. More preferably, the air, nitrogen and carbon dioxide which are incombustible and exert substantially no adverse influence on the recording material are most adequate. The liquid is preferably ≥1 kinds of, for example, fluoroalkane, perfluoroalkane, olefin, paraffin, water, wax, etc., including compds. which are liquefied by pressurization. The development to prevent the unevenness is possible in this way.