Once we have found a source of pigment, whether it be from soil, clay or rock, we must then process it to extract the pigment and make it suitable for the next stage. We start first by scrubbing the rock to remove any impurities like moss or sand.
The rock must be smashed with a hammer, and fragments of the rock can shoot off and cause injury so it is recommended that eye protection is worn at this stage. Place the rock onto a tea towel on top of a durable plastic like a chopping board, preferably outside on the ground and then cover the rock with the other half of the tea towel and using a large hammer, very carefully smash the rock into powder, collecting all the dust. The tea towel and chopping board will get ruined with lots of holes in them. Transfer the rock particles into a pestle and mortar to grind to a superfine powder. Whilst earth pigments are considered safe to work with and do not pose a threat to health, any powder that can be inhaled can be dangerous, therefore a mask should be worn when working with powders.
Professional paint makers will ensure that their pigment particles are ground to a specific size, as the finer the particles, the better quality the paint will be, however, this isn’t always practical for the home maker. It is possible to buy or make your own sieve with the required micron size, but it is not necessary.
I found that depending on my source material, I could struggle to get my particles finer than sand so on occasion I used a coffee grinder to help with the final step. Bear in mind a coffee/ spice grinder is not made for this task as the particles could be a lot harder and it could cause the grinder to stop working. Anything that is used for pigment making, including tea towels, chopping board, sieve, mortar and pestle, grinder etc should not be used for food. Once the particles are as fine as we can get, we move onto levigating or washing the pigment.
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