 The most complex shots, where the live-action actors interacted with the stop-motion animation, were achieved via two different techniques, the Dunning process and the Williams process, in order to produce the effect of a travelling matte.The Dunning process, invented by cinematographer Carroll H. Dunning, employed the use of blue and yellow lights that were filtered and photographed into black-and-white film.Bi-packing of the camera was used for these types of effects.