An apparatus for producing viewable images is disclosed in accordance with the teachings of the present invention wherein a character pattern comprised of modulated radiant energy is transmitted onto a surface of superconducting material disposed in an external magnetic field. The external magnetic field is less than a critical field value such that the transmitted modulated radiant energy is effective to maintain certain portions of the surface of superconducting material in their respective normal states in accordance with the character pattern when the ambient temperature is decreased below a critical temperature value, whereby magnetic flux penetrates said certain portions. Upon decreasing the ambient temperature, the superconductivity of said superconducting material is obtained and the penetrated magnetic flux is trapped in said certain portions to form a magnetostatic latent image of the transmitted character pattern. The magnetostatic latent image is then developed to form a viewable image of the character pattern. Alternatively, the superconducting material initially admits of its superconducting state and the transmitted modulated radiant energy is effective to quench the superconductivity of certain portions thereof whereby magnetic flux penetrates said certain portions. The penetrated magnetic flux is trapped in said certain portions upon the restoration of the superconductivity thereof.
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