| 摘要 |
PURPOSE:To obtain reflectivity and recording sensitivity stabilized at prescribed values by previously aging an optical card under specified environmental conditions until the reflectivity and recording sensitivity attain the prescribed values, then subjecting the card to recording of information. CONSTITUTION:The gelatin of the film base of the medium formed by laminating the light reflection film of the surface layer for which a silver salt photosensitive material is used as a stock and the film base consisting of gelatin absorbs moisture and swells, then the silver particles of the surface layer are diffused into the film base when such medium is previously subjected to the aging under the specified conditions. Since this change is irreversible, the once diffused silver particles do not gather near the surface layer and are maintained in the stable state even if the optical card is thereafter dried. The reflectivity and recording sensitivity stabilized at the prescribed values are, therefore, obtd. when the optical card is subjected to recording of information after the card is subjected to the aging under the specified conditions. The aging is preferably executed under the conditions of 35-50 deg.C temp. and 85-90% relative humidity.
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