Sunday, April 4, 2010


I don't normally use a green in my palette. In the past, I've made my greens by mixing yellow and blue together. So I thought it would be fun to make a new color, and try out some new preparation techniques at the same time.

The Old Masters would have had limited sources of green pigments. Bright greens would have been derived from copper. Malachite is a mineral form of basic copper carbonate. A cheaper synthetic copper green, known as verdigris, was widely used as well. This was made by tarnishing copper. A sheet of copper was placed inside a jar full of vinegar. The green that formed on the surface could be scraped off and ground into a pigment. Verdigris is considered inferior to the natural mineral, so I chose not to use it.

Malachite has a blueish-green color, very similar to the patina one finds on copper metal left outdoors.

Malachite is lightfast, but sensitive to the acids found in oil paint. This fact has lead many experts to not recommend its use. However, it's well preserved in many Old Master paintings, so there is reason to believe that some of these concerns may be misplaced. There is evidence that in more well-preserved pictures, copper pigments were coated with some kind of protein. This protein formed a protective barrier around the pigment particles that stabilized them. I came across a treatment along similar lines developed by the artist Michael Price, and decided to try it.

The basic technique is a process known as levigation. It takes advantage of the fact that larger particles are heavier and settle more quickly in water than smaller ones. You add water to the pigment, stir the mixture , and then pour off the contents. The larger particles settle quickly and are left behind, the finer go with the water. With this method, one can separate a pigment into a whole range of different particle sizes. In practice, its difficult to get a very precise separation.

By adding protein, we are able to make this method more effective. The source of our protein will be a solution of eggyolk and water.

The malachite is first crushed into a coarse powder in a mortar and pestle. This powder is washed in water several times, then allowed to dry. Malachite is moderately toxic, so I always wear gloves, a respirator, and work outside on calm days.

Crushed malachite being washed in water.

I prepared the water/egg mix.

I slowly added the mix into the malachite and stirred them together.

You can see desired effect as I tilt the bowl. The larger particles have settled to the bottom.

The liquid is then poured off into another bowl, leaving the sediment at the bottom.

The process is continued over and over again, creating more and more bowls full of finer and finer particles. They are left to dry.

After they had dried, I went back and reground the coarsest pigment again.

The malachite is ground on a marble slab with a muller. This was followed by more protein treatment. I ended up repeating the whole process over again three times.

I'm very satisfied with the final color. I feel it was worth all of the work in the end.

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