Aqueous deacidification - with calcium or with magnesium?

In order to check the validity of the arguments recently presented against aqueous deacidification using Mg(HCO3)(2) four old papers representing the types "brittle ground-wood", "quality groundwood", "chemical pulp" and "rag", and three types of laboratory handsheets (chemical pulp, cotton and unbleached linters, as used in the reporting institute for leafcasting together with deacidification) have been submitted to different aqueous treatments or production methods resp.: Ca(HCO3)(2) and Mg(HCO3)(2) solution, demineralized and tap water. Because in the previous reports contrary behaviour of relevant samples during dry and during moist accelerated ageing has been emphasized, the samples have been submitted to both methods of accelerated ageing and then checked for mechanical strength, colour change, pH, DP and mineral content. The evaluation of the widely diverse results is bringing about four main conclusions: there is no clear superiority of one aqueous deacidification method using earth alkaline carbonate conservation research should take into account the situation of practical conservation work and avoid overinterpreting chemical details an urgent need of conservation research would be a method of accelerated ageing imitating natural changes more closely than the methods usual at this time.