Plant Pigments – Experimenting and Searching for Green

Generally I don’t use the plant pigments because they’re fugitive, meaning they fade over time. Sometimes they completely disappear.

However, I’ve found two sources that actually intensify with exposure to light (full sunshine) and so I am experimenting with extracting the pigments from them.

The Sources of my Plant Pigments

Sassafras makes a nice yellow and orange, whereas Black Gum makes tan and green.

The differences in the colors produced from one plant are due to a few different things.

First, the time of year matters. If I gather leaves early in the season, sassafras gives me yellow. If I gather the autumn leaves, I get the orange. These two colors are sheer in nature but can become quite bright with UV exposure.

If I make lake pigments by adding an alum solution and following with calcium carbonate to flocculate and collect the precipitating pigment, I get yellow from the autumn leaves of sassafras and a very nice green from the black gum.

Maybe other shades will result from using other solutions in this lake process. I’m only beginning the experimentation. Then I’ll also test the finished paints from this way of getting the colors to make sure that they, also, are light fast and UV safe to use in a painting I don’t want to fade.

Many organic and even metallic inorganic will also oxidize and turn brown. This has been a big problem with any plant pigments I’ve used too, except the sassafras. I’m still testing the green from the black gum to see if it’ll turn brown.

How to Test the Color Stability

I test by leaving half of my test strip outside so that it gets full sunlight exposure and open air for 4 weeks. At the end of the 4 weeks I compare the other half of the strip that has remained inside in the dark to the one that hung outside.

A little bit of change is tolerable, but too much indicates that the painting won’t look the same after a decade or two. Watercolors are fragile colors to begin with and I always frame mine, and recommend buyers to frame theirs, under conservation glass to protect it from UV light, even indoors.

Precipitated Plant Pigments

Here’s what the filter cakes from my lake experiment looks like. I’ll write up a full post about what I did and how it looked throughout the process later.

Plant pigments obtained from precipitating with alum and calcium carbonate.
The yellow lump is from the autumn leaves of sassafras and the green one is from the autumn red leaves of black gum.

Where to find my Paints

I sell my collections at Etsy and through my online shop at Wild Ozark, the main website. Eventually I’ll have raw pigments to sell, too, for those who want to make their own paints of any sort from Wild Ozark colors!

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