The phenomena that yellow ochre when heated converts to red ochre has been known since the Paleolithic, which not only makes it the first synthetic pigment but also the earliest form of pyrotechnology, using fire to alter the chemistry of a naturally occurring material. This heating transformation process was also used to increase painter’s palette including Caravaggio and Rembrandt.

Inspired by this traditional colour transformation technique of burning colour, Colombian designer Laura Daza created a series of stepheating experiments to characterise the thermally induced transitions. Various degrees of heat will produce a series of shades from yellow, red and reddish brown.

Burnt sienna explores this colour making technique by heating yellow ochre, which magically transforms into a series of reddish shades, and is translated onto contemporary objects such as textiles and vessels.