jer@peora.UUCP (J. Eric Roskos) (10/09/85)
Recently a small accident while developing some VPL film has made me notice
something interesting about color negative film. Whatever the properties
of the image may be, the color of the color mask on the film seems to
be very sensitive to variations in processing.
The color mask is present, supposedly, in order to correct for the fact
that certain of the emulsions are sensitive to colors other than those which
they are supposed to be sensitive to (although I've never seen a convincing
explanation of exactly how this works, it is claimed that this is why
color negative film gives better color rendition than reversal film).
I'd noticed in the past that when developing with exhausted developer, the
color mask would turn out almost grey, rather than yellow/magenta.
However, when I accidentally used developer that was too warm by a few
degrees on VPL film, the color mask turned out an extreme magenta color, so
magenta that I had to use no magenta color correction, and adjust the
yellow and cyan to correct for it (and then the colors came out a little
strange). (The mask on VPL film usually is more magenta than on VPS and the
VR films).
Since that time, I've noticed that the color of the mask seems a very
sensitive indicator of correct developer temperature and development time.
VPL seems more sensitive to this than the other films, although the others
also show slight variations, particularly related to how many times the
developer has been reused. I don't know why this is, however.
--
Shyy-Anzr: J. Eric Roskos
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