GUMS
Contents
What is a Gum?Examples of Gums:
Works Cited
What is a Gum?
Gums are described as water-soluble, plant exudates made from polysaccharides. These materials have been used as adhesives and binders in watercolors, pastels and in some emulsions (The Organic Chemistry of Museum Objects).
Examples of Gums:
Gum Arabic – Also referred to as acacia gum, gum Arabic is harvested from plants found in the Middle East, Northern Africa and West Asia. It is water-soluble and has a variety of uses including printmaking, paint and ink formulation (i.e. watercolors), and cosmetics.
Gum Tragacanth – This water-soluble gum is obtained from plants native to the Middle East. Although not as common as gum Arabic, tragacanth is widely used in foods (gum paste), in the tanning industry, and is the primary binder used to make pastels.
Gum Elemi – Elemi is a plasticizing resin collected from trees in the Philippines and can be used to plasticize lacquers and shellac. It is soluble in aromatic hydrocarbons such as toluene and somewhat soluble in alcohol.
Gum Ammoniac – This gum is collected from the Dorema Ammoniacum tree native to Iran. It is generally dissolved in water and then strained to remove impurities. It has been used as a mordant for gilding and can be re-activated with heat and moisture long after it is applied.
Fruit Tree Gums – Gums obtained from cherry, almond, apricot, peach, and plum trees are said to possess similar properties, though cherry has been referenced more frequently in artist’s recipes. If these gums are allowed to harden they must be placed in water for a long period of time until they swell and turn into a gelled substance. Fruit gums have been referenced in ancient recipes and may have been used as additives to paints (especially for manuscript painting) and varnishes.
Works Cited
Mills, John S., Raymond White, “Carbohydrates: Sugars and Polysaccharides” in Organic Chemistry of Museum Objects, Reed Educational and Professional Publishing (1994): 76.