"Earthen Rainbow: Working with Wild Clay Terra Sigillata at Midrange" is an article I wrote describing the experience of learning to notice clay, reconnecting with the land, and how it's inspired my studio practice. It's also a technical guide for other clay artists. I turned the article into a zine to share my experiments and explorations collecting and using wild clay to decorate my pottery and as a way to encourage others to dabble with free, local materials in an accessible way. I share process, recipes and insights, letting you into my studio practice. Lots of photos of clay samples, test tiles, as well as finished pieces utilizing this technique. The zine is available in print or digital (including a printer spread file so that you can print your own.)
To be clear, there are no proprietary secrets in the zine. You can find information on how to identify wild clay and recipes for terra sigillata all over the Internet. This was just a creative way for me to communicate my personal journey, observations and perspective to inspire and educate. 
Excerpt:
"Working with wild clay terra sigillata at midrange temperatures is a way to celebrate and honor the infinite variety [found in nature]. In its raw state, clay can appear in a range of colors – blue, gray, orange, pink, yellow, green – often indicating the presence of iron. When fired at low temperatures, these diverse hues tend to flatten into a common iron red or dark orange. However, firing to midrange temperatures (in my case, cone five) allows some clays to melt, vitrify, and develop unique characteristics, moving beyond that initial phase. While the most common result I’ve achieved is a dark, semi-gloss iron red, I’ve also been able to uncover an incredible variety of tones beyond that. Pushing the firing temperature into the high range would likely cause many of these clays to turn brown, potentially losing the subtle variations I’ve come to appreciate. I haven’t tested this yet, as I primarily work with midrange materials, but the results at cone five have been rich and rewarding, showcasing the depth and diversity of wild clay."
In "Earthen Rainbow," I explored the range of sheen and tone that different naturally occurring clays can produce. However, as I mentioned in the article, the most common result I get is some variation of iron red or a deep reddish-brown. I didn’t include this helpful image in the zine, so I’m sharing it here instead.
Many clays that appear yellow, gray, green, or pink in their raw state turn a similar reddish-brown when fired because of the presence of iron. Iron is a common element in natural clay, even if it's not obvious at first glance. During firing—especially in an oxidizing atmosphere, like in an electric kiln—the iron in the clay reacts with oxygen and transforms into iron oxide, which is essentially rust. This oxidation process gives the clay its warm, reddish-brown or terracotta color. The raw color of a clay body can be influenced by many factors, including organic material, mineral content, or how water has moved through the soil over time, but once the iron oxidizes in the kiln, it often becomes the dominant visual element.
Even among these similar results, I notice subtle variations in undertone and sheen. Some iron reds lean more orange, while others have a cooler, purplish cast. The finishes also vary—some appear satin, others more matte. These differences are more noticeable in person than on screen. Despite their similarities, I use them differently on my pots, pairing each one with glazes and terra sigillata that best complement its unique character.
The image below is of a terra sigillata that becomes a glossy, semi-translucent glaze at cone 5. It's a clay sample from Abiqui, New Mexico.
