From: Fred Camper (email suppressed)
Date: Tue Oct 30 2007 - 09:32:38 PDT
For most 8mm and 16mm projectors that I'm familiar with, the answer is
50 per cent.
What often varies is how many blades the shutter has, and hence how many
times during the viewing of a single frame the image goes to black. Two
and three bladed shutters are common for reduced flicker. The old Bolex
8mms that would do 5 fps had nine-bladed shutters, for relatively
flickerless 5 fps projection.
You can often determine this by viewing the shutter optically, or by
advancing it with an inching knob while looking into the gate.
For info on FrameWorks, contact Pip Chodorov at <email suppressed>.