A printer failure which is disconcerting and often difficult to trouble shoot is a flash in the matchline at a scene change. Usually the matchline starts dark and a very short period of time later it corrects itself. This is usually caused by a solenoid releasing too slowly. It is difficult at times to note this in checking the printer operation since the time involved is so short. As the condition progresses and the flash becomes longer it is easier to locate the faulty solenoid. If lubrication with a dry lubricant such as molybdenum disulfide or Molycote (a liquid lubricant must never be used) does not correct the trouble, the plunger should be checked for burrs, otherwise the solenoid should be replaced.

    The feather step schedule should be checked with the microscope occasionally and corrections accurate to at least scale division should be made. Due to the symmetry of operation the sum of the readings for steps 1 and 6, 2 and 5, 3 and 4 should be a constant to insure proper blending for all feather schedules.

    It should be noted that for the six focus steps there are only three feather schedules available, so that each feather schedule must handle two focus steps. It should be noted that it is impossible to locate any feather schedule so that it does not give trouble (show the camera vignette) for some camera focus positions. (Fig.9). In fact some of the final feather schedules do not even look like they are best compromise positions when compared to the overlap schedules for final camera alignment. These changes become necessary when a schedule based on the data was tried out and it was found that too many of the scenes showed camera vignette for various reasons. As a result, the final schedule was gradually adjusted to improve the bulk of the scenes as much as possible while harming the remaining scenes as little as possible.


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