How to make pigment from azurite and malachite (part 2)

This blogpost is the second part of two from one of my handouts “How to make pigment and paint from azurite and malachite” made for my class on how to make pigments held at Cudgel Wars in Aarnimetsä AS LIII. Part 1 can be found here.

 

How to make pigment and paint from azurite and malachite

written by Silwa af Swaneholm

About the stones
The two cousins azurite and malachite are pigments that were often found on the medieval palette and used in manuscripts. They are both copper ore stones and while azurite is blue the malachite is green. According to Thompson malachite is a changed form of azurite and contains “a higher proportion of combined water” (The materials and techniques of medieval painting. p.161).

Azurite can be blue but also comes in shades that are more greenish, that probably means that the shades with more green has more malachite in them. Malachite can have many shades from blue-green to green-blue and I guess that depends on the amount of azurite remaining in the malachite. You can buy azurite stones which you can clearly see have pieces of malachite in it. I prefer to buy azurite clusters that seem to have very little malachite in them and then malachite stones in various shades of green.

Malachite

Cennini says that malachite is a half natural color produced artificially and that it is formed from azurite. He recommend to buy the pigment ready-made. He also says that one should work up the pigment with a light touch because if you grind it too much it will become gray. After moulding it should be worked and rinsed in water. He recommend stirring it in water and then rest for 1-3 hours before pouring of the water. If you do this the pigment will become more beautiful.

Malachite where not often called by name in the paint makers books, Cennini called it verde azzurro, “blue green”, when referred to it passes as blue green, mountain green and sometimes as gold solder since malachite was in the antique era and in the middle ages used for soldering gold.

“Malachite has a green color that does not fade over time or when exposed to light. Those properties, along with its ability to be easily ground to a powder, made malachite a preferred pigment and coloring agent for thousands of years.” https://geology.com/minerals/malachite.shtml

So as for azurite the malachite must be ground fine, but not too much because of the pigment turning gray. Both of the stones requires according to Cennini cleaning before making paint of it but in two different methods. I have made malachite paint without cleaning the malachite with a satisfying result.

Materials needed

  • Malachite

  • Safety mask and gloves

  • Mortar and pestle

  • Slab and muller

  • Jars to rinse the pigment in (if you want to)

  • Flat spatula

  • Distilled water or rain water

  • Gum arabic

  • Honey or unrefined sugar.

  • Shells

  • Start with beating and crushing the stone/stones in a mortar. Hold the mortar so that your hand covers as much of the opening as possible while you still should be able to beat the stones with the pestle. This way you avoid having small pieces of stone and dust everywhere. When the first crushing is done you should start grinding the pieces into a powder. Please remember that too much grinding can make this pigment fade and become grayish so don’t grind the stones too fine since you are going to grind it on the slab in the next step.

  • Put your powder on the slab and then grind your dry powder with the muller. If you want to you can after grinding it choose to put the pigment in a jar.

  • If you want to clean the piment you can start this process by following this step. I do not clean malachite and if you prefer not to just skip it! To clean the pigment, put it in water and stir and then let it sit for 1-3 hours before pouring off the water. Repeat this 1-2 times and your pigment will according to Cennini get a more beautiful colour.

  • If you cleaned your pigment put it back on the slab, if not just add a small amount of water to the pigment and grind until all pigment is wet, if it’s to dry add som more water.

  • Start adding some powdered gum arabic and a drop of honey (or unrefined sugar) and work it up with the wet pigment. I sometimes prepare a mix of water, gum arabic and sugar that have had time to dissolve before I make paint. Without gum arabic and honey the grinding sound should be kind of creaky because of the size of the pigments.Since you don’t want to grind the malachite to much you add the binders before the creaky sound kind of disappear.When the sound change your paint is done. Do a small paint test to see if you used enough binder so that the pigment is stuck when the paint has dried.

    If the pigment falls off, add more gum. If the paint cracks you added too much gum and need to add more pigment. If you don’t have more pigment you need to clean the pigment again. If you want your paint more shiny add more honey or sugar. Beware of not adding too much of the honey since this will make the paint sticky even when it has dried!

  • Use a spatula to put the paint in a shell or glass jar. You can start using it right away or let it dry and use it like a watercolour

References

The materials and techniques of medieval painting. D. Thompson. 1956, Dover publications, New york

The craftsman’s handbook, “Il libro dell’arte” Cennino d’Andrea Cennini, translated by D. Thompson. 1960/1933, Dover publications, New york

Link:
https://geology.com/minerals/malachite.shtml

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