Thursday, July 6, 2017

V E R D I G R I S / Colour of the Month #5

We are celebrating Colour of the Month #5!
While living in London and traveling abroad, I have always been curious about the pale green colour seen on rooftops and domes of various churches and traditional buildings. It creates a beautiful contrast with the architecture and city landscape. 

Many historical green and blue pigments are copper based, including pigments like verdigris, azurite and malachite. Verdigris is a man-made pigment and has been manufactured using different recipes, whilst azurite and malachite are natural occurring copper ores. An alchemic process is used for making this fascinating colour by exposing copper to acetic acid.  


 ‘Green of Greece’

Source: copper
Chemical name: basic copper acetate
Colour range: pale green, bluish green, turquoise

The scarcity of natural copper minerals such as malachite and azurite, led to the development of new synthetic copper compounds in Antiquity as the technique of Verdigris. This green pigment is obtained through the application of acetic acid (vinegar) and other ingredients to copper plates, which then are scraped off and collected in a sealed container. It can also be obtained by exposing copper, brass or bronze to outside agents such as air, rain and seawater for long periods of time.

Discovered by the Greeks, meaning green of Greece, verdigris is a moderately transparent pigment with low stability; manufactured since Antiquity through the Middle Ages, Renaissance and Baroque. During the 17th century the main centre of Verdigris manufacturing was Montpellier in France and it was the most vibrant green available for painting until the 19th century, often mixed with lead white or lead-tin-yellow due to its transparency. Used as a colourant in illuminated manuscripts, book illustrations and maps by European painters from the Middle Ages through the 17th century. 

There are several different recipes for making this pigment that can be found in ancient manuscripts and traditionally it was prepared by exposing copper to the vapours of fermenting grape skins or in closed casks over vinegar. According to old recipes, verdigris was applied to paper with wine, water diluted vinegar and honey. There is a magical element in the process of manufacturing this pigment, the way blue crystals appear on the copper sheets and how it does the work for you; just let it happen.



For the process of manufacturing verdigris pigment, I used a copper metal sheet based on a traditional Greek recipe described by Theophilus, 'sprinkling common salt over sheets of copper brushed with honey and placed in vinegar'. The process is very easy but you have to wait several days for the first green crystals to appear on the metal sheet. 

Below you may find a mood-board with experiments of colour translated onto various surfaces.


Photos: Kkgas, Laura Daza