(Lost Animation Techniques used in The Secret of NIMH) Effects Supervisor Dorse Lanpher using “exeter” paper as a hold-back matte. It is a glossy black (true black) paper, the same size as the cel, with registration pegs on which we had xeroxed the line art image of the Great Owl and Nicodemus. The effects animators would, with an exacta-blade, remove the area within the eye lines for every drawing in the scene so that the eye “holes” were always in the correct position, then in a second pass on the film negative, shoot every frame with the matching “exeter” paper image without the original painted character nor the background, exposing light from beneath the glass platen at about 600%.
Then back the film up again to frame one and expose the backlit eyes a second time with just 60% and a lens blur of 40%, to spread the light in order to create a glow effect around the eyes. We did this same effect with the glowing flowers and other elements when Mrs. Brisby is making her way to the Rats den. Also, for the highlights on the amulet and its chain and for the finale with the sinking concrete block home and all of the fireworks of its resurrection.