DAMMAR

also spelled Damar, or Dammer, any of a variety of hard varnish resins obtained from coniferous trees characteristic of Southeast and East Asia, including Shorea species (especially S. wiesneri), several species of the family Dipterocarpaceae, and a few species of Burseraceae. The resin obtained from S. wiesneri oozes from the tree in a soft viscous state. It is highly aromatic but loses its odour as it hardens upon exposure to form a transparent, brittle, straw-coloured film. Dammar is readily soluble in alcohol. It is much-esteemed in Asia for incense burning and is also used in plasters, varnishes, and lacquers. Rapid-drying lacquers are formulated using dammar in combination with nitrocellulose. A solution of dammar in chloroform or xylene is used to preserve and mount thin biological sections for microscopic examination. With oil of turpentine, dammar forms a fine varnish that dries clear, smooth, and hard; it is a widely used picture varnish.