There seems to be no end to the list of things upon which artists have chosen to paint. Wooden panels and later, stretched canvases have become the norm, but before that, and in modern times, the choices artists have made as the holding surface for their paints have been rather mind-boggling. They range from the sublime to the ridiculous. Miniatures have been painted on surfaces as small as a pea and murals on surfaces as large as entire buildings. Starving artists have been known to paint on burlap, cardboard, window blinds and flat rocks. The wealthy have used gold and silver. I once painted on two layers of bed sheets gessoed together. One layer seemed too thin so while it was still wet I stretched a second over the first and re-gessoed it. Actually it was a pretty nice surface. I've even been known to nail burlap over the back of a picture frame and carefully gesso the front. Look Ma, no stretchers!
In 1520, the Florentine painter, Giovanni della Robbia, teamed up with the sculptor, Giovanni Francesco Bustici, to paint on clay. The sculptor crafted large, terra-cotta panels in sections much like a jigsaw puzzle. Once they were leathery, the back of each panel was carved out to lighten the weight, then they were allowed to air dry. When bone dry, they were carefully fired in a wood kiln. Once removed and cooled, they were turned over to the painter who applied special mineral pigments carefully chosen to withstand the intense heat of a second, glaze firing. The palette was limited--blue, yellow, purple, and green. Once the painting was done, a transparent glaze was applied over the work and it was refired. The results were often quite spectacular, low-relief paintings marrying the best efforts of the sculptor and the painter that, though fragile, could often withstand the ravages of time, fire, and water better than any other surface.
These two artists collaborated to create Christ and Mary Magdalene, a large work consisting of over 30 terra-cotta pieces mounted as an altarpiece. Conceived in two parts, the lower section is a highly detailed and sculpturally realistic confrontation between the two figures in the garden. It is unique because the figures and background were white and only the sky is actually painted; and because of the fact that it was done in a golden yellow. (Later works by the two artists were much more colourful presentations.) The upper part, a semicircular arch depicts God, holding a book, flanked by two putti. Earlier, around 1480-1520, another artist, Guido Mazzoni, sculpted and painted a free-standing group of terra-cotta figures for San Giovanni Battista, in Modena, Italy. His grouping of seven mourners around the dead body of Christ, which lies out on the ground before them, at first glance, looks like something from a modern-day wax museum. His Lamentation is a frozen moment from a medieval religious drama--striking in its realism, startling in its emotional impact.