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A transparent, colorless, water soluble fish glue. Isinglass was originally made from air bladders of the great Russian beluga sturgeon, Acipenser huso, found in the fresh waters of the Caspian and Black Seas. After restrictions were placed on Russian exports in 1939, other fish air bladders were used and isinglass became a generic term for glue derived from the swim bladder of various fish, e.g., North American isinglass is made from hake or cod. To prepare isinglass, the air bladders are removed from the fish, cleaned and air dried. The dried bladder is cut into thin translucent strips. These strips, which are nearly 80% collagen, are dissolved in hot water then diluted and cooled into flat disks. The very strong, water soluble adhesive can be used in low concentrations. Isinglass is used as a clarifying agent in the manufacture of fish glue. It is also used as a size for handmade paper and has been used in Russia as a paint medium. Sturgeon glue is rarely available outside of Russia.

Synonyms and Related Terms

ichtyocolle (Fr.); colla di pesce (It.); ichthycoll; ichthyocolla; sturgeon glue; Bombay purse; Brazilian lump; Penang pipe; Saliansky glue; East India shred; Russian isinglass


  • Isinglass is brittle at relative humidities below 50%.
  • Isinglass is degraded by UV light and bioorganisms

Physical and Chemical Properties

  • Soluble in water
  • pH = 6.0-7.5

Resources and Citations

  • S. Foskett, "An Investigation into the Properties of Isinglass", Scottish Society for Conservation & Restoration Journal, 5(4), Nov. 1994, p.11-14.
  • G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 423
  • R. J. Gettens, G.L. Stout, Painting Materials, A Short Encyclopaedia, Dover Publications, New York, 1966
  • Ralph Mayer, A Dictionary of Art Terms and Techniques, Harper and Row Publishers, New York, 1969 (also 1945 printing)
  • Matt Roberts, Don Etherington, Bookbinding and the Conservation of Books: a Dictionary of Descriptive Terminology, U.S. Government Printing Office, Washington DC, 1982
  • Dictionary of Building Preservation, Ward Bucher, ed., John Wiley & Sons, Inc., New York City, 1996
  • Book and Paper Group, Paper Conservation Catalog, AIC, 1984, 1989