120 film in 220 backs

Discussion in 'Medium Format' started by vernon_jenewein, Feb 12, 2016.

  1. I am using 120 film in 220 backs for my Bronica. I have read and been told that you can do this with 120 film
    (use in either 120 or 220 backs but the 220 film needs the 220 back or it won't get flat enough. It is just a
    little tighter rolling in a 220 back for me.

    Has anyone else done this?

    I would think that you would also get a flatter film that way as the specs are tighter for 220 than they are for
    120 film on the pressure plate.

  2. 120 film has backing paper the full length of the film. 220 has blackout paper at the lead and trail but no paper along the film length. The film base is 3.5 mil to 4 mil thick depending on manufacturer. Backing paper is 6 mil thick.
    120 film in a 220 back may be too tight to advance properly. If the back will accept either set to 120 for 120 film.
    If the 120 film winds correctly in your 220 back then you will have to wind on from frames 11 to 20 before loading the next roll.
    Good luck.
  3. Would there be any issue with scratching the emulsion if the film is very tight against the rails?
  4. Probably varies by back and its condition.
  5. david_henderson

    david_henderson www.photography001.com

    You can use 120 film with a Bronica 220 back- or more particularly with a 220 insert since the shell of the 120 and 220 backs are the same. No discernible difference in picture quality. Be aware of the following
    In my experience winding the 120 roll gets tighter and tighter as you progress through the roll and the bulk of the roll-see Mr Monday's post above- gets bigger. For me this stiffness was enough to make me wonder whether I may damage something in the winding area.
    A 120 back on a SQ series camera counts to 12 and won't let you take more pictures on that roll. The 220 back/insert counts to 24 and so will allow you to happily take pictures after you run out of film. You can of course keep a close eye on the counter, but I think its very likely that you would at some point take "pictures" with no film.
    So in short, possible but not ideal/as good. Better to have a 120 back or insert if you can find one. I considered this as something I did when I had to, not something I'd want to do as a matter of course.
  6. The lack of good quality (unless you pay through the nose) of 120 backs on eBay may be a relationship to the lesser quantity of 220 films. Thanks, Mr Henderson and Mr. Monday for the insights.

    Yes, you could run out film (more than likely) after 12 exposures with 120 film and take pictures on nothing. Good news it won't cost you anything for printing those. Bad news, you will never get a chance to re-take those pictures you "thought" you had taken as a general rule. Light and subject are fleeting moments in time. There were no second takes with Zapruder and JFK filming...

    On Mr. Monday's comment above about whether there might be scratches, I don't think the back would have so much to do with it, as there is paper against the pressure plate in the 220 back. I think it would come from how well the rails and etc were on the body of the camera for any chance of scratching.

    Since I only have 120 film, then I must be diligent in paying attention to the counter. Taking off the back and finish winding the film after the count of 12 so that it can be exchanged.
  7. Find a 120 back and get it serviced. 220 backs are a dime a dozen because very little film is made in that size. With what film costs today it doesn't make sense to fool around with it.
  8. At frame 12 there is still film at the film plane, at frame 13 the trail edge of the film is still at the edge of the take up roller on the insert so its probably best to advance to frame 15 before opening the back. Also the extra thickness of the film + backing paper could cause spacing errors so you may only get 10 1/2 or 11 frames per roll, geared film advance, or 13 frames due to overlapping with a clutch film advance.
  9. I have some 220. my saGULL 203 HAs a wind lever s possibly I can use 220.
    I just wonder id the film is too long to fit a developing reel.
  10. No, Walter, look here: http://www.bhphotovideo.com/c/search?atclk=Category_Developing+%26+Processing+Supplies&sts=ma&ci=761&N=4294204213&Ntt=220+darkroom+reel
    I think I have one of these in my darkroom supplies out in the shed. http://www.bhphotovideo.com/c/product/40287-REG/Paterson_PTP119_Auto_Load_Adjustable_Reel.html/prm/alsVwDtl
  11. My regular tanks are FR specials they are small and hold 1617 oz
    i WILL SEE..
  12. There is no spacing errors because Bronica uses a "gear" system. If anything you might get an extra exposure, but don't count on it.

    I took apart both a 220 and 120 insert, specifically, the pressure plate. I measured both the pressure plate, the screw with the plastic spacer, etc. Depth of the amount that the plates recess when pressed, etc. I could not find enough difference , < 0.001" in any measurements using a digital caliper. Baffles me that there would be more issues with 120 (with it's paper backing) used in a 220 film insert over the 120 insert.

  13. The only difference between a 120 insert and a 220 insert will be the the distance the pressure plate is from the guide rails if any exists at all. The thicker material of 120, film + backing paper, may result in more film being pulled through per wind. It will depend on the gearing. It may make a .1mm to .5mm difference in film spacing with the narrower measurement at the beginning of the roll. The more film+backing paper on the take up spool the more film+backing paper will be pulled across the pressure plate as the take up spool increases in diameter as the film is advanced.
    120 film backs on cameras, Mamiya RB67, Graflex Graphic Roll Film Holders, (the ones I'm familiar with) started having spacing problems when the film thickness was reduced by 1 mil due to newer materials. The cure is to increase the take up roller diameter by .010 inch. I have never had the pleasure/dishonor to work on a Bronica.
    Some if not all Fuji films are .5mil thinner than other brands. Some cameras will have overlapping/frame edges touching with Fuji films while correct spacing will be obtained with other brands of film.
    I do not know what problems if any you will encounter if any at all. The only way you will find out is to run some film through the holder. I frequently run the backing paper from a processed roll through the holder marking the film gate edges of each frame as it goes through the assembled holder then look at the marks once complete and the paper is unrolled. Actual film spacing will be .1mm to .3mm wider than the backing paper only.
  14. Take up spool size should not be a factor. Wouldn't matter if the roll ended up the size of a full roll or toilet paper. The gears determine how much advances from one frame to the next, not clutch or anything else. The camera body winds the next frame and does so by precise number of movement of teeth.

    How, exactly, does the camera "know" that there is film in the magazine? An empty insert does not advance film numbers, nor does it cause the body to be ready for the next picture. There is no apparent means of the film insert to know when film is in there and to signal to the camera that there is film in the holder that I could see.

  15. How, exactly, does the camera "know" that there is film in the magazine?​
    Basically there is a cam that is a part of the gearing or the teeth of one gear are spaced differently so that the take up is turned a specific amount based on the counter position. A lock release lever for frame advance indicates a cam system. A 4 mil film will build up at a specific rate so the spaces in a cam system or the gear teeth spacing is calculated accordingly. Running a thicker material will cause the take up to increase in diameter faster than a thinner material therefore pulling more off the supply spool.
    Repeat, I do not know what you will experience with your roll holder. I am stating known possibilities.
    If you put a clock face on a take up spool and mark its position at frame one and advance slowly enough to count the turns and fractions of a turn you will find that the take up spool turns a different amount for each frame. The supply is spring tension dampened so that it does not spin freely and unroll film needlessly but other wise unrolls when pulled.
  16. There are two sets of rails. The outer set is where the pressure plate comes to rest. This leaves a gap between the pressure plate and the inner set of rails which is just slightly bigger than the film thickness to allow the film to pass freely.

    This gap is larger for 120 than 220 by the thickness of the backing paper.

    To make a 220 back suitable for 120, shim the outer rails to leave a bit more gap for the film plus backing paper using pieces of tape.
    Despite its name, the pressure plate should not put any pressure on the film.
  17. Almost sounded plausible, Steve. However, at lunch I carefully looked over my backs. I only have 1 ea 120 insert and it was on an older style back. I took out the dark slide from the "shell" of the backs. I then put the 120 insert in a newer style back and the 220 in an older style back. Both without dark slides. I can easily fit a 0.006" feeler gauge between the rail and the pressure plate on the 120 insert and quite a bit more snug on the 220 insert. Both without dark slides, of course.

    If that were the case, about the body rails, then moving 120 inserts into other body "shells" that have/had 220 inserts into them would be the same issue with tight film winding. But what is interesting, is without the dark slide that pressure plate looks like it is resting on the inner rails, not outer rails as I only saw one rail it was touching (both sides). When I get home I'll take off the plate and check again.
  18. There must be a time limit to edit, or else I'd go back and edit and say that Steve Smith stands corrected. I was wrong. I measured the plate at 2.660" wide, and the outer rail is not near that distance from each other. I was wrong. The plate does rest on the outside rails. But, if that is the case when why would a 120 insert work in any back and work better for advancing film? Granted, that the 120 will have the right and proper number of frames for doing the right count of picture, but if the rails are the key point, then even though the picture count would be right then the film would still advance a lot harder in the wrong shell.

    I'll try the pieces of tape concept and also do some more measuring to find the real 120 back I took this insert out of.

    The feeler gauge is still baffling. I would think I could use that feeler gauge to find the single 120 "shell" that I have that came with the 120 insert.

    Did I mention Steve Smith is absolutely right!!

  19. The edit time is roughly 10 minutes from the time of the post. The edit must be completed in that 10 minute edit time.
  20. I followed Steve Smith's advice, or suggestion but did it a little different. I took the pressure plates off and added a very thin strip of our adhesive label material to just the out edge, probably no more than 0.020" wide, just so that it caught the edge and did it on both sides, JUST the surface facing the rails. re-assembled the pressure plate and put the insert back into the holder shell. Ran my 0.006" feeler gauge between the outer sides with the back and insert assembled (no dark slide) and the feeler gauge showed clearance now, just like on the 120 back. Loaded 120 film into the back and as advancing, the stress to get the film advanced was CONSIDERABLY less than it was before, and WAS LIKE HAVING 120 film in there. I did it to all my 220 backs that way.

    Now, when I looked at all the 220 pressure plates, compared to the 120 pressure plate I notice that the very edges of the 220 are milled just a few thousandth thinner than the 120. In fact the 120 pressure plate has no milling indication at all. Jimmy Koh of Koh Camera in NY was telling me this was the only difference, besides the counter mechanism, and he was right.!! It is all in the pressure plate and how it rests on those outer rails. 220 has milled pressure plates to give the film without backing better flatness to the inner rail. 120 has no milling.
  21. Photo illustration of 120 vs 220 plates:
  22. 220 pressure plate. NOTE the slight milled edge to allow the plate to rest a little closer to the film with no paper backing.
  23. 220 plate with self stick label just on the very edge to allow more thickness, simulating the 120 plate. I put the label on and used a razor blade to trim the edge of the paper.
  24. 120 pressure plate is 0.063 overall whereas the 220 plate is 0.063 overall except the sides that meet the outer rails and then they are only 0.058" thick, at that small edge, to allow the film, with no backing paper, to rest flat on the inner rails.
  25. Vernon,
    Thanks to your first two photos - of the flat-edged 120 and milled-edge 220 plates - I just wanted to take the opportunity to point out that they basically also illustrate how the switchable 120/220 pressure plates in some cameras/backs work.
    A back insert for the Mamiya 645AF(D) line, for example, has a 180 degree rotating pressure plate. It has a pattern of flat and milled strips along the edges, but the patterns on the left and right sides are opposite. The outer guide rails inside the back itself are broken into a complementary pattern of several mm of rail, several mm of a gap, and so on. At the plate rotation for 120 film, the flat-edged strips of the plate sit on the strips of rail in the back. At the plate rotation for 220 film, the milled-edge strips of the plate sit on the strips of rail in the back, and the flat-edged strips of the plate drop into the gaps in the rail, so the whole plate sits further forward. It's a clever system.
  26. By the way, all these photos were taken with my Tracfone LG Ultimate 2 camera, and not on high resolution either. Not too bad for displaying on the web, huh? Auto focus as well. Always have some kind of camera with you I say.

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