n.a highly polished, semitransparent paperUNESCO 2001Glassine paper is a supercalendered, smooth, dense, transparent or semi-transparent paper manufacturer primarily from wood pulps, which have been beaten to secure a high degree of hydration of the stock. It is grease resistant, and has a high resistance to the passage of air and many essential oil vapors used as food flavoring and, when waxed, lacquered, or laminated, is practically impervious to the transmission of moisture vapors.Roberts 2007, 83Loose stamps and those stored in glassine envelopes should be transferred to archival stamp stock books or archival enclosures.Ritzenthaler 2010, 376Glassine: A dense, glazed, semi-transparent paper used for interleaving and to make enclosures, especially for storing photographic materials. Historically, the method of manufacture gave highly beaten fibers an acid surface treatment, although neutral pH glassine (made translucent with glycol) is currently available. Glassine is hygroscopic, dimensionally unstable, and thus unsuitable for preservation use. If it becomes damp or wet, it can adhere to other surfaces, including photographs or other materials it is enclosing.
Glassine is often used to make envelopes to store photographic negatives. However, it is inappropriate for archival use because it easily dissolves in water and absorbs moisture from the air.