Deacidification of library materials

A method of deacidifiying books, imaged paper and other imaged material having a cellulose base comprising treating said material with suitable alkaline particles of a basic metal selected from the group consisting of oxides, hydroxides and salts having a predominant particle size between 0.01 and 0.9 micron and a surface area between 50 and 200 m.sup.2 /g BET, dispersed in a gas with deposition enhancement by aerosol impingement, filtering through the paper or electrostatic attraction or dispersed in a liquid, in an amount and for a time sufficient to pass into the interstices of said imaged material and increase the PH of the material and provide an alkaline buffer without impairing the image thereon, said liquid consisting essentially of an inert halogenated hydrocarbon and a surfactant.