Roll filmback Q?-what about those...for? : LUSENET : Large format photography : One Thread

Just curious! This is actually applicable to RFBs of any format including those on some old 35mms. There are regularly knocked concave dots on the pressure plate of RFBs. I wonder what they are made for? Why not being made into a glossy surface? Is this something to do with film flatness? I would appreciate your knowledge on this. Thanks!


-- Dongyun Hao (, December 12, 2000


I think the purpose is to provide small air pockets between the pressure-plate and the film. This reduces friction by lessening the contact area and preventing a partial vacuum forming under the film.

-- Pete Andrews (, December 12, 2000.

According to the folks in Florida, these are known as "dimpled chads" and are there to create confusion. Glad to be able to clear this up for you.


-- Doug Paramore (, December 12, 2000.

Those of us in Florida need to count all those dimpled chads. Please inspect the pressure plates of all of your cameras. If you find those dimpled chads, please mail the cameras to me for counting.

Thanks for your help in ensuring a quick resolution.

John Brevard County, Florida

-- John H. Henderson (, December 12, 2000.

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