ISPRS-Annals ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences ISPRS-Annals ISPRS Ann. Photogramm. Remote Sens. Spatial Inf. Sci. 2194-9050 Copernicus Publications Göttingen, Germany 10.5194/isprs-annals-XI-4-2026-421-2026 Research on Deacidification Treatment for Addressing the Acidification Crisis of Map Archives Li Ming 1 Hu Fen 2 Bai Ju 1 Feng Lifei 3 Yu Hao 1 Peng Yunlu 1 National Geomatics Center of China, Beijing 100830, China Land Satellite Remote Sensing Application Center, Ministry of Natural Resources of P.R. China, Beijing 100048, China Sichuan Ruili Heritage Preservation Technology Co., Ltd., Chengdu, Sichuan 610225, China 10 07 2026 XI-4-2026 421 426 Copyright: © 2026 Ming Li et al. 2026 This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/ This article is available from https://isprs-annals.copernicus.org/articles/XI-4-2026/421/2026/isprs-annals-XI-4-2026-421-2026.html The full text article is available as a PDF file from https://isprs-annals.copernicus.org/articles/XI-4-2026/421/2026/isprs-annals-XI-4-2026-421-2026.pdf

Map archives, serving as crucial cultural heritage documenting historical spatial information, face severe challenges in long-term preservation. To evaluate the feasibility of deacidification technology in the conservation of map archives, this study utilized 41 severely acidified early 20th-century map archives as samples. These were treated using a specific non-aqueous deacidification technology, and changes in pH value, color difference (ΔE), and inks stability before and after treatment were analyzed. The results indicate that after deacidification, the paper pH value significantly increased from an average of 4.48 to a range between 8.24 and 8.87. The color change was minimal, with an average color difference ΔE of only 1.62. This study verifies that the deacidification technology is suitable and effective for the deacidification treatment of acidified paper-based map archives, providing a safe and reliable method for preserving their cultural value.