PROPHASE(OPCSDEFS) Optical Printer Control System PROPHASE(OPCSDEFS) NAME prophase - configure projector's phase adjustment for 1:1 shooting USAGE prophase [chan] [pulses] # sets number of pulses channel # will move before shooting 1:1 EXAMPLES prophase a 200 # half-stepper systems (400 ppr) prophase b 200 # prophase a 1000 # Centent microsteppers (2000 ppr) prophase b 1000 # prophase a 1600 # Lynx microsteppers (3200 ppr) prophase b 1600 # DESCRIPTION Sets the projector phase adjustment (in motor pulses). Phase adjustment occurs just before and just after 1:1 ratio shooting. This phase adjustment is necessary so the projector(s) and camera can run together, only exposing film when the projector images are seated. Almost without exception, the prophase command: 1) Is always set to be 1/2 the number of pulses for one motor revolution. This includes Vistavision movements. On a system where one switches back and forth between Vista / 35mm / 16mm, the prophase value does NOT change, even though the PPR(OPCSDEFS) value may change. 2) Is set ONLY for the projectors. A value of '0' should be set for all the other channels. (The prophase value is actually ignored by the other channels, so it doesn't really matter what the values are for non-projector channels, but '0' makes it easy to tell that the value is ignored by these channels.) BUGS None reported. SEE ALSO RAT(OPCS) - set the shooting ratio for the REP command REP(OPCS) - shoot current projector/camera shooting ratio PROPHASE(OPCSDEFS) - sets projector phase adjustment for 1:1 shooting MATH(DOCS) - math expressions (for use in frame specifications) SYNTAX(OPCS) - Online calculator and OPCS math expression syntax ORIGIN Gregory Ercolano, Los Feliz California 12/15/89