Retreatment of a Print Damaged by Excessive Sodium Borohydride Bleaching

Abstract

Abstract An etching that was visibly damaged as a result of previous bleaching with a 5.6 % aqueous sodium borohydride solution underwent retreatment involving washing to stabilize the embrittled paper and to remove potentially present bleaching residues. During a final immersion in a dilute calcium hydrogen carbonate solution administered for deacidification, an unexpected and severe blistering occurred that is explained as a recurrence of previous bleaching-related blistering. The blisters were laid down. The treatment concluded with a consolidation of the bleach-damaged paper surface using a 0.5 % gelatine solution applied by misting.