Maria Martinez, a member of the Tewa-speaking pueblo of San Ildefonso, learned to work clay as a child. She collaborated with her husband Julian to produce ceramics: Martinez built and shaped the pots, and Julian painted the designs. In the 1910s, Maria and Julian developed the black-on-black style. Working with local red clay, Maria coiled her pots by hand; the decorations were painted with a refractory clay, which turns matte when fired. In order to blacken the red clay, the fire is smothered in horse manure and wood ash to remove all oxygen from the air and carbonize the pots. After Julian’s death, her daughter-in-law Santana took over the painting role.