How we made brown pigments from eucalyptus bark: a step by step guide

Hey everyone! Last week my fellow resident Myungah and I made brown color pigments from eucalyptus bark. The eucalyptus tree grows all around Messejana, where I currently participate in an artist residency program. Here is a step by step guide through the process, which is called "laking".

Feel free to let me know how you like it!

eucalyptus bark in pot

step 1

First, we placed the bark pieces in a pot. We used about half of the pot; then we filled it up with water until all the bark was covered in water. Then we let the mixture simmer for about an hour. I personally would say open all the windows in the kitchen or do this outside if you can, because I had the feeling that the steam of eucalyptus made me a little dizzy :D

step 2

Next, we strained the mixture using a sieve, collecting the liquid in different jars. We had prepared several glasses of liquid, because we were playing around with the pH value, which resulted in different shades of brown (see picture below). I personally like the rusty red brown :)

laking and filtering

step 3

In the next step, we added Alum and Soda Ash to the liquid. That process is calles "laking". What I usually do: I dissolve around 10-15 grams of Alum in warm water and mixed it with the color liquid. In the meantime, I dissolve 5-10 grams of soda ash in a glass of water. I use measurement spoons, because it makes the process easier than weighing each time. After allowing the liquid and Alum to sit for about ten minutes, we added the soda ash liquid to the solution. As a result the solution started to bubble and solidify. It was nice to observe this transformation through the transparent jar, which is why using a larger container is advantageous.

step 4

Now, it was time to be patient. We allowed the solution to rest before filtering it. That takes about an hour.

step 5

Once the laking process was complete, we prepared coffee filters to separate the paste from the liquid. This step can take some time since coffee filters work slowly. Typically, I wait for approximately an hour, adjusting the waiting time based on the number of filters use. As mentioned in step 2, we aimed for different browns and since I do only have one filter pod, we had to be a bit patient here :)

filtering through coffee pad

step 6

When the filters didn't contain any water anymore, we layed them out on paper towels. To speed up the drying process, I usually also spread the paste on the coffee filters. As mentioned in my previous guide, don't leave the pads out in the sun to dry. I know it dries way faster, but the color will fade significantly. Therefore, be patient and allow the paste to dry naturally, which usually takes a few days. I guess the exact amount of drying time depends on how much liquid is still left in the coffee pad.

brown pigment paste drying on coffee pads

step 7

Once the paste was dry, we carefully scraped it off the pad and transferred it to my mortar.

I do have basic mortar from an Asian wholesale store, which works well for this purpose. But it is kinda heavy, so I could not take it to Messejana. So I went to another wholesale store here and they had a fine and small mortar, that served very well. This will be my travel buddy from now on :) You can see it on the picture below.

In the last step, we filled glass tubes with the powdered pigment and marked them.

This was an experiment first, because I wasn't sure if eucalyptus would even turn into color pigments. Also I wasn't sure if it might be too oily for painting purposes, but it did well on paper as you can see in the picture below :)

Hope this guide helps all, who want to make their own pigments. I am in a trial and error phase myself, so if you have any remarks regarding the correctness of my process, let me know :)

much love,

esrin