According to Walter Murch, CLAYMATION was an integral part of his conception of the film from the beginning. The principal antagonist whom Dorothy must confront and defeat in this new adventure in the Nome King, an evil being who, in the company of his faithful nomes, moves through solid rock as if it were water. Murch had seen Will Vinton's THE LITTLE PRINCE at Marin County Film Festival several years earlier, and had always imagined that CLAYMATION was the ideal technique for bringing these rock creatures to life.
When Murch first visited the Vinton studio in Portland, Oregon, the script for RETURN TO OZ was in its first draft. The characteristics, powers, and design of the Nome King were hammered out in the discussion with CLAYMATION Director Will Vinton, Art Director Barry Bruce and other artists from Will Vinton Productions studio even as Walter Murch and co-writer Gil Dennis revised and polished the story.
One of the first issues to be addressed was the look of the clay itself. It was not difficult to match the color of the rock samples Murch sent, but getting a rock-like texture was more difficult. The addition of various materials from sand and walnut shells tried. Finally an aggregate of small black rocks was settled on. The addition of these rocks required many adjustments in the closely guarded and delicately balanced clay formula in order to get a consistency that could be easily moved for animation. To give the clay a burnish rock surface, small rocks were dipped in water and used to shape the clay as in was animated.
In the course of the film, as the Nome King captures and imprisons each of Dorothy's friends, he gradually becomes less rock-like and more human. Dorothy first encounters him on a rocky ledge where she and her companions have fallen after their flight from the castle of the Wicked Witch Mombi. At this stage the Nome King appears in the cliff wall with features barely distinguishable from the natural rock formations which fissure and rumble as he speaks. Later, in his Throne Room -- a cavernous chamber in the bowels of the mountain -- the Nome King becomes more and more human. His head emerges from the rock wall. The outlines of a body become visible. Hands and arms emerge. Eventually human eyes fill the rough-hewn sockets, and the rock surroundings his body begins to form into a robe of sorts.
At the dramatic climax of the film, Dorothy begins to gain the upper hand, freeing her friends from the Nome King's power, and the Nome King begins to regress and decay until he is finally reduced to an angry pile of rubble.
The OZ production required extensive matching of CLAYMATION with live-action photography. CLAYMATION Art Director, Barry Bruce went to London's EMI Studios during pre-production to work with Production Designer Norman Reynolds, to coordinate design of the sets with the design of the Nome King. During principal photography either CLAYMATION Director Will Vinton or CLAYMATION Producer David Altschul were there for any shot which related to the Nome King or nomes. They consulted with Walter Murch on live action background shots into which CLAYMATION Nome King and nomes would be composited.
They took extensive notes, snap shots and drawings that would enable them to match composition, lighting and texture. While Actor Nicol Williamson recorded his lines in England to be used in the clay sequences, reference film was simultaneously shot. This was referred to by the animators at Vinton's studio in Portland, as they matched the Nome King's lip and body movements to the actor's movements. The animators also used TV monitors to track movement. These were particularly important where movements were more rock-like than human. In scenes like Nome King on the ledge, or the spy sequences, the faces tend to stretch and fissure in very complicated ways.