There is a report from the research that the aged deteriorated paper would generate organic acids. Photographic enclosure that is made of paper, and an experiment was conducted to confirm the possibility of influence on photographic image in accordance with deterioration of the enclosure for long preservation and to specify the type and amount of the organic acid generated from accelerated aging of enclosure. The organic acid detected by the experiment was extremely small amount (several ppm), and a significant increase in organic acid due to the deterioration of paper could not be identified. At least the organic acid generated from the enclosure would not be the main factor for deterioration of the photographic image.