Lamination

From DictionGloss

Lamination is a now obsolete but once popular method of strengthening fragile documents by placing them between two sheets of cellulose acetate film and then between two sheets of thin transparent tissue paper and then pressing the whole package together while introducing heat. The heat causes the layers of material to bond to the original document. This was a standard practice in libraries and archives between 1930-50. It can be reversed by immersing the document in repeated solvent baths to loosen the layers. Acetone is an effective solvent for this purpose.