35mm Film on 120 Spool

This adapts 35mm film for use in 120 medium format cameras. By using this, you get full exposure of the film strip, sprocket holes and all.


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10/23/14 - Added matching takeup spool http://www.youmagine.com/designs/120-takeup-spool-for-35mm-film

10/7/14 - Added a combined STL

7/6/14 - I've added a PDF Read Me guide to using the adapter

6/16/14 - updated files to improve fit and reduce friction. May be loose on some commercial canisters but will now fit CineStill film and possibly Kalt. Print using 50% infill.

Tested and working. This adapts 35mm film canisters to work as a 120 format spool, and allows shooting 35mm film in any 120 medium format film camera. The 35mm film is centered on the 120 spool. Using this adapter allows using films that are not available in 120 format, and the entire 35mm film is exposed, resulting in images out to the edges, sprocket holes and all, resulting in a unique effect.

See http://www.youmagine.com/designs/120-takeup-spool-for-35mm-film for the matching takeup spool.

Do not force adapters on. Make sure the splines are aligned and if tight, trim/sand or wiggle on carefully. The splines may need to be trimmed to fit Kalt bulk loading canisters and some others.

The hole for viewing the film number (usually a red window) on the camera must be taped over with black gaffer's tape or some suitable opaque tape to avoid back side exposure of the film. You will need to wind blindly about 1-1/2 turns at the beginning and taper down to 1-1/4 turn at the end. Most medium format cameras have no rewind, so you will need to unload the film in a darkroom or changing bag and manually rewind the 35mm film back into its canister. When processing, specify "process only" and "do not cut" and cut the film yourself.

These were designed for the Flyer 6x6 camera developed as a result of the Pinhole Printed Kickstarter project (pinholeprinted.com) but can be used in any 120 medium format camera.

The combined STL is printed as is. If using the individual parts, the bottom STL part is printed as is and the top STL part must first be rotated 180 degrees about X or Y to sit flat on the bed for printing. Now recommending 50% infill due to the small cross-section of the splines.

If you do not have a 3D printer or have it tied up with other things, check at http://www.pinholeprinted.com/order/35mm-film-to-120-spool-adapter/ for alternatives.

This is CC by SA 3.0 - this means anyone can freely print or even sell the adapters - but you must provide attribution if you do so. You can print a tag with this information:
35mm Film on 120 Spool by coconnor55Published May 2, 2014https://www.youmagine.com/designs/35mm-film-on-120-spoolCreative Commons - Attribution - Share Alike 

and display it if demonstrating your printer capabilities or distribute it with any copies you sell.



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01cd637351c1372b53532307dc2e11ab?default=blank&size=40boopidoo printed this ago
Carousel thumb 20140430 35mm 040714012
Printed on:
Prusa i3 MK3S
Printed in PLA and 15% infill. In Prusaslicer I added an infill modifier so that the more delicate cebter parts was printed solid.
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Mini screen shot 2013 09 30 at 16.40.44a.mediumClint commented ago


Most 120 cameras have a red window on the back for 120 film which shows the frame number printed on the paper backing of 120 rolls. Cameras that support 220 film don't have a red window since that would expose the film and use a film advance counter instead. Often there is a pinch roller that drives the film counter but since 35mm film is so much narrower than 120, it doesn't engage the pinch roller. That looks to be the case for the Mamiya 6 from what I can tell in photographs of the open back. You will just need to load the 35mm film with 3 turns on the takeup spool, mark the exposed portion with a marker, and count how many lever winds are necessary to advance past the exposed portion with at least 1/8" between frames, and remember it for future use. You will know when you reach the end of the 35mm film because you will feel the resistance to winding. Don't force it. At that point, you unload the camera in a changing bag or darkroom and wind the 35mm film all the way back in for processing (I don't know of a 120/220 camera that supports rewinding).

F7a57189a583f5f884e8f0424b5e411e?default=blank&size=40vflacher@gmail.com commented ago

Hello Clint,

I printed it today and it's looking very good ! Except that I can't figure out why the film counter does not advance when I try to load a 35mm film with it on a mamiya 6. Do you have any clue ?

Thank you for your help,


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Mini screen shot 2013 09 30 at 16.40.44a.mediumClint published this design ago