A new technique for the removal of red fungal stains on traditional Chinese painting on silk

The orange-red to reddish purple fungal stains on paintings and textiles are recalcitrant to be alleviated even by using oxidative methods that are corrosive to most organic materials. A novel approach of alternate applications of sodium borohydride solution with dilute acids were tested and successfully practiced on the removal of the red fungal stains on a severely disfigured traditional Chinese painting on silk. The new approach was compared with the conventional oxidative method of potassium permanganate-oxalic acid solution in terms of their effectiveness and the safety of the silk fabrics. 1% and 0.5% of sodium borohydride ethanol solution alternated respectively with dilute acetic acid and sulfuric acid were effective for the removal of the reddish fungal stains on an authentic traditional Chinese painting on silk as well as the silk fabric samples. The loss of tensile strength of the silk fabric samples induced by the new approach was much milder than did the conventional oxidative method of potassium permanganate-oxalic acid.