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Improvement can be made here, though it entails a fair amount of redesign to
get all sensitive filters into a cooler part of the optical system. A disconcerting
and particularly frustrating phenomenon occurs rarely when the coils of the
lamp filament contort and short out electrically when the lamp is turned on
causing large exposure changes and some color shift. This can be avoided by
applying voltage gradually when starting a lamp and never thereafter turning it
off during the course of a day’s operation. During periods between actual use,
the lamp would be operated at reduced voltage keeping the lamp hot and reducing
the thermal shock of starting with a cold filament. Printer #2 is set up this
way.
Another serious source of error between panels can originate
in the mattes used to effect scene to scene color changes. If different mattes
are used for each panel, differences in the wear or fading characteristics can
result in brightness and color differences between panels in the prints. The
errors can be eliminated or considerably reduced if only a single matte is used
for all three panels. To do this, however, requires that the negatives be
delivered from the camera without color differences or serious exposure
differences between the panels. The difficulty of matching and maintaining
separate mattes for each panel is so great that many minor and some serious
color errors have been allowed to remain in the picture so as to avoid this
complexity. The only good way to effect color changes between panels is to
utilize a completely automated additive light source rather than the
subtractive type source we use. The source should operate with steps of .02 density
units, accurate to about .005 density units.
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