Well, what do you know? I stand corrected!

As to camera damage, never saw it in 13 years of about 1 million feet of polyester a year through precision Oxberry and Mitchell camera movements in our optical printers and film recorder.

Only damage I ever saw as a direct result of polyester was a bent film processing rack on our continuous processing machine.

But, it never hurts to be safe, I guess...

I have seen camera damage as posted here and elsewhere.

Kodak follows the same guidelines as Ilford in film base use. The only place polyester is used is in space photography where weight and film length is of concern. Kodak coated on 2 mil (0.002") support or thinner to meet NASA specs.

PE

Kodak coated on 2 mil (0.002") support or thinner to meet NASA specs.

I bet that involved some challenges. Our printers complain if we quote a job on anything thinner than 0.004" polyester.


Steve.

I agree with you concerning the 35mm format : if it can't tear, you can damage camera. But in 120, what is the problem?

To avoid damage on motorized 120 backs?

Not just motorized backs. Some cameras (Pentacon 6, Mamiya 6, Bronica S and S2) are known for having film advance issues or potential for stripped gears.

I bet that involved some challenges. Our printers complain if we quote a job on anything thinner than 0.004" polyester.


Steve.

Steve;

Not really. The problem was adjusting the film backs to use the thin based film. It was supplied as motion picture and as 120 film both. One used in the capsule mo-pic cameras IIRC and on the ground, and the other was for the Hassie in orbit and on the moon. (oh, I forgot, the moon stuff was all faked. :D )

The ground motion picture was such high speed, they needed thin film to get more footage into a standard magazine. I've mentioned before that I saw it jam and spew the camera guts along with sprocket gears all over the test lab.

The high speed camera had a gear shift type of arrangement to get up to speed so as not to damage the equipment by a sudden jolt of full power. This is also true of high speed coating machines coating polyester. They ramp up to coating speed. This of course, wastes a lot of start up footage so you have to want to coat a lot of film to make a profit and overcome waste. Experiments are done at very low speed to eliminate this problem.

Also, you must remember that polyester cannot be coated on directly. It needs a corona discharge to pre-condition the film to accept the aqueous gelatin emulsion.

PE

So, the same emulsion can be coated either on acetate or on PET, without any difference?

Just about.

PE