8mm Forum: What causes warping?

This is topic What causes warping? in forum 16mm Forum at 8mm Forum.

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Posted by Brad Kimball (Member # 5) on April 16, 2018, 10:47 AM:

Does vinegar syndrome cause warping? Is it worth buying a film if the seller states the print is warped?

Posted by Bill Brandenstein (Member # 892) on April 17, 2018, 07:43 PM:

Warping occurs when the emulsion and base no longer have the exact same dimensions. VS is the usual cause, but any other cause of shrinkage is relevant. There are all kinds of warping. Some film rolls off the reel with a strong twist and projects fine. Sometimes it will look frumpy on the reel and will still project fine. Sometimes it looks flat on the reel and won't focus side-to-side, or is shifty in the gate.

Therefore, pay about 20% what you would for a good print of the same title, accept that it's a gamble, and proceed. I've handled a lot of vinegar over the past decade, and while it has a very limited and unpredictable life span (unless stored frozen), it's still film and thus is still fun to play with and watch.

Posted by Maurice Leakey (Member # 916) on April 19, 2018, 11:00 AM:

Older IB Technicolor tends to warp, probably something to do with the colour layers.

Posted by Gilbert Lambert (Member # 5403) on April 20, 2018, 12:57 AM:

I had a mint IB Technicolor 16mm print of the 10 Commandments, it was warped but no Vinegar Syndrome.

Posted by Maurice Leakey (Member # 916) on April 20, 2018, 02:34 AM:

Regarding the purchase of a warped film depends on the degree of warp. Most 16mm projectors will accept some degree of warp through the gate, however, the main problem will be the take-up spool onto which the film may hang down egg-shaped and unless it's a short film where you can use a large spool you're stymied.
One way to achieve a good take-up of a warped film is to twist the film over as it leaves the projector and before it enters the spool.

Posted by Mark Norton (Member # 165) on April 28, 2018, 09:06 AM:

Gate temperature?

I've run some tests:

Eiki NT1 gate temperature gets up to as much as 58 degrees centigrade,(measured at the exposed top back plate) leave a length of film in the top half of the gate & it soon warps.

By comparison Bell & Howell TQ3 only reaches 41 degrees centigrade.

Posted by Maurice Leakey (Member # 916) on April 29, 2018, 02:24 AM:

I don't think gate temperature could cause warping, after all, film does go though at 24/25 frames per second.
Warping is more likely to be caused by poor storage conditions.

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