THE UFFINGTON WHITE HORSE OF OXFORDSHIRE
Our ancestors have been using chalk to create images since prehistory. The earliest chalk drawings date back to the Paleolithic era, and are up to 40,000 years old. This representational, figurative art, found in caves around the world is the earliest evidence of human creativity and abstract thought.
As those of us old enough to remember the school blackboard and their teacher covered in chalk dust will know, chalk is a soft, white, material which lends itself to drawing and writing. It's a porous limestone formed from the remains of microscopic marine organisms which fell to the seabed over millions of years. As the gleaming White Cliffs of Dover proclaim, England is rich in chalk deposits, and the seam running through Wiltshire is part of a system of chalk downland stretching from the Dorset Downs in the west to Dover in the east. I found these particular pieces of chalk just a mile from my home in Wiltshire.
Drawings on the landscape, known as geoglyphs, also have a long history. Though many of the chalk 'white horses' to be seen in the south of England date back only two or three hundred years, the Uffington White Horse in Oxfordshire, with its strikingly bold, styalized lines, is dated to the Early Bronze Age, about 3000 years ago. In more recent times chalk, in its natural state, was a medium favoured by artists such as Rubens, Matisse and Picasso.
But chalk can also be made into a watercolour paint, with all the versatility that offers.
First you need to find your lump of chalk. Chalk looks much like its far harder cousin, limestone, so make sure it IS chalk by drawing a few test lines onto a receptive surface. You'll need a robust pot for breaking up the chalk, a hammer and a pair of goggles.
Break the chalk down in stages; first into smaller lumps ......
...... then into still smaller pieces ......
...... and finally into a crumble.
Next you'll need a pestle and mortar, or a similar arrangement, to further grind down the crumbled chalk. I added 3 teaspoons of chalk to the pestle and mortar.
Grind it well in the pestle and mortar until you have a fine powder of chalk. It's advisable to wear a mask when working with any powder.
For the next stage you need a hard flat surface to grind on, and a grinder with a flat base. I used a purpose made glass 'muller slab', with a roughly etched surface, and a glass 'muller' for grinding, but you could use a marble slab and a flat-bottomed glass or similar. The important thing is to have a good connection between the slab and the grinder.
Gum Arabic comes from the resin of certain acacia trees and is an essential 'binder' to help the paint adhere to a surface. I use my own home-made Gum Arabic but it's readily available from art suppliers. The addition of a few drops of honey further improves the texture of the paint, making it easier to lift, and helps to prevent it from cracking as it dries out. It is also a natural preservative.
Hollow out the centre of the chalk pile and start by adding 50% of Gum Arabic to chalk, so about 1 1/2 teaspoons. Add the honey later.
Using a palette knife begin to blend the chalk and the Gum Arabic together, adding more Gum Arabic if necessary to get a smooth, fluid mixture.
The purpose of 'mulling' is to make sure that the Gum Arabic 'binder' is attached to every surface of the chalk particles. Work the muller in small circles, regularly bringing the mixture back to the centre with the palette knife.
To begin with the grinding will sound gritty, but as you carry on mulling the sound will soften. It's important to carry on mulling for as long as it takes to achieve a good texture - this could be ten minutes, twenty or longer.
Add water, drop by drop, as necessary to keep the mixture flowing smoothly and add a few drops of honey at this stage. Test the mixture from time to time on a surface and add more Gum Arabic if necessary, until you feel you have a paint you can work with.
...... in little paint pans, filling them half way and allowing that to dry before filling to the top. Once dried out these will keep indefinitely.
PS Substituting the Gum Arabic for an oil, such as linseed or poppy oil, will give you an oil paint.
References:
britannica.com
ruralhistoria.com
geolsoc.org
wikipedia.org.
metmuseum.org
kremer-pigmente.com