A radiation image recorded in a stimulable phosphor sheet or plate is visualized by stimulating the phosphor with stimulating rays. Being stimulated by the stimulating rays, the phosphor emits detectable light. The emitted light is detected by a photodetector. The wavelength of the stimulating rays is selected within the range of 600 to 700 nm. The wavelength of the light detected by the photodetector is selected within the range of 300 to 500 nm.