Method for revealing hidden watermarks

摘要

A method for temporarily revealing the presence of a watermark on cellulose-based materials. The method comprises applying one of a perfluorocarbon ard hydrofluorocarbon to at least a portion of the cellulose-based material. The method also provides applying a solution containing both perfluorocarbon and hydrofluorocarbon to the cellulose-based material to vary the rate of evaporation of the solution.