Over the past two decades, the Library of Congress has been at the forefront of the development of deacidification processes that can be applied en masse to large collections. In its search for an ideal mass deacidification process, the Library invented a

Over the past two decades, the Library of Congress has been at the forefront of the development of deacidification processes that can be applied en masse to large collections. In its search for an ideal mass deacidification process, the Library invented and further developed the diethyl zinc (DEZ) gaseous process and also brought about key improvements in solvent-based, liquid phase processes. In the conservation science community, gaseous processes have traditionally been deemed to have a significant edge over liquid phase, solvent-based processes, mainly because they preclude any possibility of adverse effects on inks, dyes and colored pigments in manuscripts, color plates and book covers due to bleeding or softening of inks.