Isolation of fungal species from test samples and maps damaged by foxing, and correlation between these species and the environment

After initial tests carried out on 20 stained paper samples from different centuries, we have devised a non-destructive method for taking samples from foxed areas of ancient maps. The stains were examined in normal light (NL) and then with fluorescence; we then checked whether fungal colonies were not developing in areas that did not respond to electronic excitation. Samples were taken using gauze–cotton swabs from fluorescent areas only. We found that fungi did develop, in the areas of the paper samples that were not clearly visible (NL) but fluorescent, when they were placed inside humidity chambers. It was confirmed that there is a correlation between the thermo-hygrometric parameters and the place of preservation and a relationship between the environment and the fungal species. We found cellulosolithic fungi and bacteria. We recommend early identification of “discolouring” with fluorescent methods in order to arrange suitable thermo-hygrometric conditions for preventing development of the infection.