How do I test the registration?
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- Created on Thursday, 27 September 2007 01:32
- Last Updated on Friday, 14 December 2012 20:15
- Written by Richard Garbutt, SOC
- Hits: 6689
Registration tests are tricky and have to be exact, so Richard Garbutt wrote this (with compositing in mind):
Once you've shot your clips, (which you've carefully labelled on the mags as well, so you don't confuse them) retire to the darkroom, rewind to the beginning (if you don't have darkroom rewinds, this is why keeping the clip to 50 feet or so will save you frustration) and relace each clip in the same mag it was shot in. Be sure you haven't rethreaded farther in than your marked frames.
Back in the light, dock your first mag back on the camera. Remove the lens, and use the inching knob to bring the first marked frame into the gate. If it doesn't line up with your first aperture marks, undock the mag, release the perf off its indexing pin, and move it so the aperture will line up. Replace the mag. Move the chart on a diagonal a distance roughly 1/3 the distance between your grid lines. Remove your ID tag from the chart - you only need to expose that info once.
Have the lab process it all. Now, view the ORIGINAL NEG on a projector with no masking aperture plates in its gate. Do NOT look at a print - this just adds the printer as a possible variable.
Without aperture plates in the projector, you should see the sprocket holes projected as well. Wander up to the screen and stare hard at them: they should not move, relative to the screen. If they do, there is a problem with steadiness in the projector movement. It's also a great time to squint at the upper and lower edges of the perfs to see that your camera is not putting any little nicks in them, which would indicate a worn camera pulldown claw.
If the perfs are nice and steady, then it's time to look at the grid. If you do not see the double-exposed grids moving with respect to the perfs or each other, shout Hallelujah, because that means your camera is fine. If the grids move with respect to each other, your camera is exhibiting weave, and needs servicing - possibly the movement (which is why it's good to check with more than one mag) or mag tension too tight. If both grids move in sync with respect to the screen, it's another clue the projector movement needs work.
This registration test is absolutely essential if you're hoping to do compositing work. And if you're going to do comp work, you should be using pin-registered camera gear.