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How to make a dummy roll for 120 film


edwinv

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Hi,

I am testing my caemra back on a bronica and seieng that my film counter is not working.

So i decide to run a dummy roll thorugh it.

But i do not want to waste a real roll as i think that i will have to run a dummy roll through the back a couple of times to verify if it works.

 

But how do i make a dummy roll ?

Do i only use the backing paper fomr an existing and process roll and wind it up on an empty spool or do i reuse the now useless emulsion layer to and put it back to its backing paper (because of the thickness) and rewind both to a spool and see if the counter gear processes correctly ? (ofcourse, once i tihnk it is all again, i'll put a real roll through for ultimate test but first i need to figure out where the issue with the back is)

 

So... how do i make that dummy roll ?

Thx,

edwin

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Then how does a frame counter know when frame 1 has been reached? Since only the backing paper is pulled through until close to frame 1.

You insert the backing paper between two rollers. Forward until the arrows point to the marked positions. Close the back. Forward the film until the two rollers feels the added thickness, and the winding is stopped at frame one. Brilliant when invented back in the mid 30's. No more red window.

I have no idea how this is implemented in other cameras.

Niels
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Oh, so 'Fandom' is now the authority on camera frame-counting mechanisms?

I have no idea how this is implemented in other cameras.

Most use a rubber friction roller or spiked roller pressing on the backing paper to actually meter the length of film/paper that's passed. There are exceptions like the Kiev60 that just use rotations of the take-up spool, but we know how reliable they are!

Edited by rodeo_joe|1
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Oh, so 'Fandom' is now the authority on camera frame-counting mechanisms?

 

Most use a rubber friction roller or spiked roller pressing on the backing paper to actually meter the length of film/paper that's passed. There are exceptions like the Kiev60 that just use rotations of the take-up spool, but we know how reliable they are!

 

And, as noted earlier, you line up arrows at the beginning, as it knows the distance from the arrows to frame 1.

 

So, I think backing paper alone would be fine. If it uses the arrows, no need to check the thickness.

-- glen

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There is plenty of new 120 film for low prices,

less than $5 for Fomapan 100.

 

There is plenty of expired film on eBay, some more, some less expensive.

 

There are also rolls of exposed film, of unknown age, some of which sell for more

than unused film.

-- glen

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