HISTORICAL MATERIALS/TECHNIQUES

COPALS

Contents

What is a Copal?

“A copal is a hard, natural resin obtained directly from tropical trees, but also found as fossil remains. These resins are very hard, almost completely insoluble and have a high melting temperature. Their very low solubility makes them irreversible in cleaning operations, as confirmed by a few cases where their use as a paint varnish was identified” (Chemistry for Restoration 175).

Examples of Copals:

Manila Copal – Soluble in ethanol, this copal resin originates from the Agathis alba tree in Indonesia and the Philippines. As it is collected directly from the tree, it is not a fossilized resin. Manila has been used in spirit varnishes and as an additive to varnish/paint recipes.

Pontianak – Collected from the Agathis trees in India, this copal resin is similar to Manila as it can be used as a spirit varnish (dissolved in ethanol). Pontianak does exist in fossilized/semi-fossilized form and would require further processing for it to be soluble in oils or turpentine.

Madagascar – Madagascar is one of the many copals originating from East Africa and for a time was prized for its high degree of hardness. The former can be collected from the ground as a fossil or semi-fossilized resin and originally comes from the Hymenoea verrucosa tree. It has been used primarily as a varnish although may have been used as an additive in varnish/paint recipes.

Congo – This fossil resin is one of many copals harvested in West Africa. Like Madagascar copal, it is valued for its hardness and originates from the tree Copaifera guibourthiana. It has been used primarily as a varnish although may have been used as an additive in varnish/paint recipes.

Kauri Copal – Originating out of New Zealand from the Agathis australis tree, this high quality fossilized resin is becoming more difficult to find. After it has been processed (run), it becomes increasingly soluble in turpentine solvents. Kauri has been mostly used as a varnish or varnish additive (especially with oil varnishes). It has a reputation of producing some of the finest varnishes that are very resistant to blooming in environments with high humidity. (Not Pictured)​

Works Cited

Matteini, Mauro, Rocco Mazzeo and Arcangelo Moles, “Varnishes, Adhesives, Consolidants, Fillers” in Chemistry for Restoration: Painting and Restoration Materials, Nardini Editore. Florence Italy (2016): 175.