Physicochemical characterization and deterioration condition evaluation of three primary documents of Costa Rica's independence process

This research reports the results of the physicochemical characterization and deterioration condition evaluation of three nineteenth-century manuscripts, which are essential components of the Costa Rican documentary heritage. The documents were characterized by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), X-ray fluorescence (XRF), and multispectral photography. The documents' condition was thoroughly evaluated, and the results were transformed into an index to correlate their deterioration state with the document's composition; this was achieved by using correlation plots and heatmaps. The study revealed that the Independence Act of Costa Rica was the most deteriorated document among the three manuscripts from the year 1821. This was attributed to its acidic pH level, high zinc content, and greater exposure to light compared to the other two documents.