Choosing between energy-dispersive or wavelength-dispersive SEM spectroscopy methods for elemental distribution in deacidified paper

Abstract This study compares the performance of SEM–EDS and SEM-WDS techniques for assessing the distribution of alkaline components in paper cross-sections following deacidification. The suitability and limitations of both methods were evaluated using model paper samples treated with either aqueous sodium bicarbonate or a suspension of MgO. Detection and interpretation limits were defined based on cross-sectional profiles obtained from the bicarbonate-treated paper.SEM–EDS produced false signals that may lead to overestimation of alkaline presence, whereas SEM-WDS provided more accurate and spatially resolved elemental distribution data. SEM-WDS was applied to paper samples deacidified with a commercial MgO dispersion to assess the Bookkeeper process’s effectiveness. The resulting elemental maps were compared with micro-pH (μpH) distribution profiles across the same cross-sections. The combined approach enabled direct correlation of alkali distribution with local neutralization effects. Results confirmed significant inhomogeneity of the Bookkeeper, highlighting the need for more precise evaluation tools in conservation practice.