This is one of the oldest greens used in paints, Verdigris is french for “Green of Greece”. The color is easy to make and is best used in oil paints. The raw pigment has a bluish green color but if used in oil paints will dry in about a month to be a rich solid green color. Over the years they have tried to improve on the color but the results have been more deadly than anything.
How to make Verdigris:
WARNING pigment making of any kind can be dangerous to your health. Always use safety equipment such as gloves, eye wear and face mask. Do lots of research before you try anything. Know that any thing you do try is at your own risk.
Anciently Verdigris was made by suspended pieces of copper over a bath of vinegar in a chemically inert airtight container. Being careful not to let the copper touch the liquid vinegar. After some time of the copper corroding, open the container and scrape off the corroded copper for Verdigris.
Another method used to make Verdigris was to place sheets of copper in wine cellars or other places that had vinegar vapors for long periods of time, letting the vapors slowly corrode the metal. This corrosion was then scraped off and used as Verdigris.
A very sped up process in making Verdigris is to place copper into a bath of equal parts vinegar and Hydrogen peroxide. The copper will slowly dissolve into the liquid to make copper acetate. You will know you have copper acetate when the liquid has turned into a very rich blue color. This can then be boiled down into a solid crystallized copper acetate or let stand and slowly evaporate to leave behind larger crystallized copper acetate. Copper acetate is a form of Verdigris. Note that Verdigris made other ways will mostly be copper acetate but can also contain other impurities. Any containers you use to dissolve or boil copper acetate needs to be chemically inert. This means glass is best.
Once you have your corroded copper you need to grind it up into a powder. You can do this with a mortar and pestle, spice mill, coffee grinder or a ball mill.