(a) Slide cards. This a simple form of animation for
television. You can develop them to show such things as a line on a
graph, expose a waveshape, or progressively show lines of lettering. A
slide card usually has three layers. The top and bottom layers do not
move, but the center layer moves. The bottom layer has the information
displayed as the animation develops, and the center layer covers the
bottom layer. The top layer has the cutout from which the viewers see
the information, as the center layer moves to uncover the information on
the bottom layer.
For economical and practical reasons, the best use for television
animation is stepbystep development of specific graphics by the "pop
in" technique. For this technique, you shoot the incomplete graphic to
a specific point, make the required changes or additions, reshoot the
complete graphic, and edit the first shooting to the second. The
editing gives the viewer the impression the additional items in the
graphic just "poppedin" to the basic graphic. Television uses this
system successfully to develop 5 or 6segment graphics built up in
steps by "popin."
(b) Technamation principle. Another method to create limited
animations is technamation. This principle uses pressuresensitive
polarized materials and polarized light to create motion or a blinking
effect. For example, weather broadcasts use technamation graphics when
showing the movement of the wind or weather front on the weather map.
When a polarized light strikes a graphic with polarized materials, it
reflects an unpolarized light from all areas, except the area covered by
polarized materials, and enters the camera lens with no visual effect.
However, if you slowly rotate a transparent disk, the reflected (or
transmitted) light from the technamation material selectively goes from
matched polarization to cross polarization. At cross polarization, no
light enters the camera lens. Then gradually as the disk reaches the
position where polarization matches, more light enters the camera lens.
This principle gives the area covered with the technamation material a
blinking effect. The rest of the graphic does not blink because it does
not reflect polarized light. This effect is successful in cases where
action is repetitive. Whether you use this principle for a band motion,
circle expansion, flashing, etc., it cycles according to the rate you
turn the polarizing disk.
You can use either front or rear lighting for this principle. When
using rear lighting, you must cut the graphic in the areas containing
the technamation materials so light passes through.