Posted: 2015-05-30 16:17
Recently I was commissioned to remove a detracting, acidic blemish which had pervaded an attractive 19th century Aquatint. After several staged treatments which included, preliminary media ' Spot ' tests, mechanical surface cleaning, a preliminary pre-wash, Calcium Hydroxide Deacidification, a dilute, 0.5% vw Calcium Hypochlorite solution 10 minute bleaching, 5 minute ' Anti-chlor ' immersion and a final resizing with SCMC (Sodium Carboxymethylcellulose) a satisfactory reduction of the stain was achieved.
The cause was traced to the hardboard backing used in the framing process. An intermediary lining of Acrylic Polyester Film was inserted between the reverse of the print and the hardboard after reframing to prevent any future migration.
The result post treatment.