Thanks to the XIV century treatise on painting by Cennino Cennini, we have a detailed account of how icons were produced at the time of Duccio di Buoninsegna; the process begins by carefully selecting antique wooden panels, which are then primed with a rabbit skin glue and a fine gesso in an operation called ‘imprimatura’.

The surface is polished to a mirror’s smoothness and Armenian bole (Armenian earth with fish glue) is applied to prepare a base for those areas to be covered with 23 karat gold leaf. The gilding is done by applying leaves of gold over the bole that has been wet with pure water. The gilded panel is then burnished with an agate stone, producing the effect of golden mirror.

 

The panel can be enriched with ornamentation in gold relief (worked in plaster) and with other designs and engravings where needed, such as in halos, flourishes and frames.

 

The painting is done with egg tempera, a highly refined method with great pictorial qualities.

The pigments and natural earths are emulsified with egg yolk, which confers resistance and brilliance.

The painting methods described by Cennini are followed in order to preserve the whole style and spirit of the original works.