8mm Forum: Maurizio's Excellent Explanation!

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Posted by Andrew Woodcock (Member # 3260) on August 06, 2015, 11:20 AM:

Having just read an old post on here that has come back to life due to John in Gretna, I have to thank Maurizio for his superb explanation on a matter I thought I understood, but clearly I didn't properly and my understanding of this design being speed related was totally incorrect I've learned.

Maurizio explains regarding the shutter design on Eumig 9 series and Bauer / Silma machines...

"I hate doing this, but if Andrew was referring to the Bauer/Silma projectors (Studioklasse and cheaper), their shutters are supposed to work in a totally different way: in fact regardless of the speed, the shutter's blade will have the same dimensions when the projector runs in forward. When in reverse, the additional blades, which in FWD mode remain hidden by the main blades, switch in position thus enlarging the main blades; that's to prevent ghosting on part of the screen in reverse, because that would happen with these machines, given the peculiar shutter cam, which provides a very fast claw arm movement; which is great in FWD mode but would lead to a certain degree of ghosting were it not for this feature. As a proof you can just watch the same footage in FWD mode at different speeds: the screen brightness will be the same. But in reverse there will be a slight decrease in brightness again at both speeds. Eumig 936, 938 and 940 copied the same concept. Eumigs Series 800, due to their claw being so tiny, give some ghosting in reverse on the lower side: they would have benefited of such a feature; still they're a good way to see with your eyes what I really mean, if you own a Eumig Series 800."

Thanks for explaining that one correctly Maurizio!

Your knowledge is highly valued by myself and no doubt many others here [Wink]

Posted by Maurizio Di Cintio (Member # 144) on August 07, 2015, 06:24 AM:

Hello, Andrew and thank you so much for your words. I find this forum very informative, too. Especially your posts. Best,
Maurizio

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