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I strongly feel that they are coming from the first roller after the payout. Unless the film stays perfectly on the roller, it will either ride up towards the tree and with the Christie AW3, it will cause the film to scrape against the holder during payout.

We just had our tech come and do pm at our theatre and locked down all rollers on the tree. This way they cannot swivel and cause rideups while paying out. Also, he timed the platters such that the prints are fairly tight and much more pleasing to move.

Be forewarned, timing like that makes it easier to toss a print!

I really like the idea of locking the framing knobs and thereby assigning responsibility for mis-frames to the offending operator. The only problem I have with this is how to correct for differences in studio printing. From what I've observed, there is no "standard" center of frame for the various studios. Some seem to print slightly (maybe 1/8 the distance between sprocket teeth) high and some slightly low. On my pitifully small screens, this can make quite the difference in appearance. Any suggestions?

The slight shift in vertical position at reel changes usually is an indication that the print was made by a lab using bi-directional panel printers. The height of the BH-1866 perforation on the duplicate negative is 0.073 inches, and on the KS-1870 perforation on the print film is 0.078 inches. So there is a 0.005 inch shift in the vertical position of the image between reels where the printer sprocket drove the film heads-to-tails, as opposed to tails-to-heads. If the scene has a really "tight" composition, or if your scope aperture is higher than the standard 0.690 inches (sometimes showing the framelines), this shift can be annoying.

Other shifts can occur due to variations in the setup for any optical printing or digital effects.

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John Pytlak, Senior Technical Specialist
Worldwide Technical Services, Professional Motion Imaging
Research Labs, Building 69, Room 7419
Eastman Kodak Company
Rochester, NY 14650-1922 USA
Tel: 716-477-5325 Fax: 716-722-7243

Watch those loop sizes! Short vertical scratches always appearing at the same place on the frame usually indicate a loop that was too small or too big, such that it "flapped" on a projector component that scratched the film. Don't forget that the size of the bottom loop also affects analog sound sync.

When the film is excessively curled, it can "pull-in" to the center of an undercut roller or guide bar. Excessive curl is usually due to very dry booth conditions. Keep the relative humidity between 50 and 60 percent RH if you can. Use an accurate digital humidity gauge (Radio Shack and Edmund Scientific sell fairly inexpensive ones) to measure RH.

A clip of a piece of film from the leader is also a good humidity gauge. After the film equilibrates a few minutes to the booth environment, let it hang free and observe the curl. The film should cup VERY SLIGHTLY toward the emulsion side ("positive curl"). Very dry conditions cause the emulsion to shrink, causing excessive positive curl. Very moist conditions cause the emulsion to expand, causing the film to be sticky and limp, and with a slight "negative curl". You can see this effect by breathing on the hanging film strip --- the moisture from your breath will actually change the curl. Drying the film with a hair dryer will cause the film to curl in the other direction.

As often mentioned on Film-Tech forum, horizontal or slightly diagonal scratches usually are caused when the film is not properly guided onto the platter, so a burr or rough spot on the platter surface rubs across the film as the platter rotates. Misthreaded film riding up onto a roller flange will also cause diagonal scratches.

Horizontal "cinch marks" are caused by flattening a dished or unevenly wound roll. Vertical "cinch marks" are often caused by pulling on the end of the film to tighten a loosely wound roll. Carefully rewind loose or uneven rolls to avoid cinching. Use an on-line film cleaner to keep the film clean and minimize cinching from abrasive particles being wound into the film roll.

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John Pytlak, Senior Technical Specialist
Worldwide Technical Services, Professional Motion Imaging
Research Labs, Building 69, Room 7419
Eastman Kodak Company
Rochester, NY 14650-1922 USA
Tel: 716-477-5325 Fax: 716-722-7243

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Although we installed platters over nine years ago, this one projector had its payout and takeup reels still attached, and rollers added to put the film straight through them. The takeup reel had a nice little metal roller on the bottom to feed it to the plastic roller, but alas the side of it had worn down so that it actually was in direct contact with half of the frame.

I do not know why these parts were left in tact but I removed them and installed the correct brackets and rollers in the right places. Absolutely no damaged prints since then.

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