I've just gotten myself a 220 film back today to try and shoot 35mm in my RB67 Pro for those sick panoramas. Who needs an XPAN when you've got medium format? You even get to expose the area around the sprocket holes for maximum emulsion usage. Now that's 35mm! My motivation behind getting a 220 back is twofold: one, I can use (almost) the entirety of a 36 exposure roll as the counter goes up to 20 instead of 10. If using a 24 exposure roll I think you can use the entirety of it on a regular 120 back with no problems in the counter. The other reason is that the pressure plate on 220 backs is better suited for the thickness of 135 film. I don't actually know how big of a difference this makes and honestly I don't care all that much about tack sharpness (and also the film is going to bend anyway), so if I were only shooting 24 exp rolls I'd not have bothered until I had seen the results; I would have preferred to avoid having to shell out for another back if I don't strictly need it.
I thought I'd try to document my process a bit, because there's not as much information about the minutiae of doing this online as I thought there was (at least not stuff that I was able to find). There's plenty about the fact that people do do it, but the processes that I found were either not very detailed or kind of wasteful like dragging the emulsion all the way to the take up spool on the other side! I know there are also custom made 35mm backs in existence but honestly this doesn't appeal to me as it feels like a waste of perfectly good existing backs; why reduce the number of formats you can shoot down to just one?
I would have liked to have posted this thread after I had some results, but unfortunately while I was testing, I wasn't able to get the film counter to advance with 35mm inserted, even though it worked perfectly fine with 120 backing paper. I'm not sure what the root cause of this is, because the film is advancing as expected (I watched it with the dark slide removed), and the plastic adapter thingies I'm using to attach the canister are able to rotate just as a 120 spool would.
To be honest I am no longer sure how the film counter is engaged at all. When I was playing around with my 120 back I was under the impression that both spools needed to be spinning and that this little lever at the top needs to be engaged—normally it's pushed down by the outer cassette door when it's locked shut—but clearly these three conditions aren't sufficient. If anybody knows how I might get the frame counter working, that would be great information to have as I have a mild suspicion that the gears turn differently when winding without the frame counter. Ideally I'd not want to have big spacing and waste emulsion, or accidentally overlapped exposures... This is the one hitch I have yet to overcome but it's one of the major benefits that a 220 back is supposed to have! Maybe there's not enough torque or something?
That aside, here's my process for making use of as much emulsion as possible. I measured a distance of about 46 cm from the start of the 120 backing paper to the edge of the first frame with a piece of masking tape that I attached with the dark slide off. This is where I want my 135 to start to be exposed. I cut off an extra 3 cm from there, down to 43 cm of paper leader just to add a little bit of extra wiggle room for the tape attaching the paper leader to the film leader, otherwise there's a risk that part of the frame will have tape in it. To attach the paper leader to the film leader I cut off the top and bottom of the backing paper away up to the arrow. I had to measure this so that it was centred and the same width as the film, because in earlier testing I found that the paper leader would like to wiggle around and become misaligned going into the cartridge. I cut all the way up to the arrow where I tapered it off and kept the full width of the backing paper, to make it easy to get the right length in the can and the right length on the take up spool. Then I loaded it up and cranked the winding lever four times, which I found to theoretically be the right number by respooling a developed roll I didn't care about and using it as a sacrificial roll.
Now as for unloading, you need a dark bag with this method. The unloading process is particularly annoying for me, because I haven't got access to a changing bag at the moment (my partner has one but is currently off with it in the US). Instead I took a normal backpack into the little cubby under the stairs and used that as a makeshift darkroom (with the bag as extra protection against any light that might have sept under the doors; I don't know if this will have offered enough protection, but some of the light seals on the back I'm using look like they might be rotting, so if there are leaks I won't know their provenance with certainty) and then rewound the film back into the can by hand.
Some improvements for my next roll: I reckon cutting the paper leader to 43 cm will include frame X0 or 00 or something like that on the emulsion, so for my next attempt I might cut the paper leader even shorter down to 40 cm. That feels like a lot of wasted emulsion if 43cm is enough, so I want to see the developed negatives before I run my next roll. Also, I plan to actually cut a little bit further than the arrow, to account for the half turn (okay, it's more like 160°, which is something like 2.8 cm) that the canister has to take to be seated properly in the back, and next time I'm going to secure the film to the paper leader using regular clear tape, which I think is thinner. For this first attempt I was just using masking tape because it's super quick and easy to work with, but you can really feel when it's passing through the flocking.
I need to make a mask for focusing screen. So far I've measured a distance of 12 mm on either side of a strip film in the... exposure area (I swear it has a name but it escapes me at this moment)? Anyway, making for a total height of 59 mm within expectations, so the film takes up 59.3% of the exposed area and 40.7% without sprocket holes. These percentages might be important because it seems the ground glass (65 mm actual size by 55 mm guide lines) isn't 1:1 with the film area (67 mm long axis by 59 mm short axis; the one that matters), but I'm not sure if what you see on the focusing screen is exactly what will be in frame. Either the focusing screen is cutting stuff off or it's slightly resizing what you see (or both). I could make one out of paper but it seems awfully annoying to have to take the viewfinder off to change orientation or to switch back to MF, so I haven't made it yet. I want to build something a bit more sturdy and unobtrusive. I think I'll pick up a sheet of acetate and just write on it with a small texta and that should do the trick for a quick and easy job.
Anyway my apologies if this has gotten a bit rambly. I tried to keep my writing as focused as I could but sometimes it's hard for me to actually tell whether or not something I've said is a tangent. I will post more to this thread as I make further progress on this stuff, and hopefully with some scans soon. When I get this worked out more I think I'll also take some step by step photos or maybe even record a video guide. Cheers
I thought I'd try to document my process a bit, because there's not as much information about the minutiae of doing this online as I thought there was (at least not stuff that I was able to find). There's plenty about the fact that people do do it, but the processes that I found were either not very detailed or kind of wasteful like dragging the emulsion all the way to the take up spool on the other side! I know there are also custom made 35mm backs in existence but honestly this doesn't appeal to me as it feels like a waste of perfectly good existing backs; why reduce the number of formats you can shoot down to just one?
I would have liked to have posted this thread after I had some results, but unfortunately while I was testing, I wasn't able to get the film counter to advance with 35mm inserted, even though it worked perfectly fine with 120 backing paper. I'm not sure what the root cause of this is, because the film is advancing as expected (I watched it with the dark slide removed), and the plastic adapter thingies I'm using to attach the canister are able to rotate just as a 120 spool would.
To be honest I am no longer sure how the film counter is engaged at all. When I was playing around with my 120 back I was under the impression that both spools needed to be spinning and that this little lever at the top needs to be engaged—normally it's pushed down by the outer cassette door when it's locked shut—but clearly these three conditions aren't sufficient. If anybody knows how I might get the frame counter working, that would be great information to have as I have a mild suspicion that the gears turn differently when winding without the frame counter. Ideally I'd not want to have big spacing and waste emulsion, or accidentally overlapped exposures... This is the one hitch I have yet to overcome but it's one of the major benefits that a 220 back is supposed to have! Maybe there's not enough torque or something?
That aside, here's my process for making use of as much emulsion as possible. I measured a distance of about 46 cm from the start of the 120 backing paper to the edge of the first frame with a piece of masking tape that I attached with the dark slide off. This is where I want my 135 to start to be exposed. I cut off an extra 3 cm from there, down to 43 cm of paper leader just to add a little bit of extra wiggle room for the tape attaching the paper leader to the film leader, otherwise there's a risk that part of the frame will have tape in it. To attach the paper leader to the film leader I cut off the top and bottom of the backing paper away up to the arrow. I had to measure this so that it was centred and the same width as the film, because in earlier testing I found that the paper leader would like to wiggle around and become misaligned going into the cartridge. I cut all the way up to the arrow where I tapered it off and kept the full width of the backing paper, to make it easy to get the right length in the can and the right length on the take up spool. Then I loaded it up and cranked the winding lever four times, which I found to theoretically be the right number by respooling a developed roll I didn't care about and using it as a sacrificial roll.
Now as for unloading, you need a dark bag with this method. The unloading process is particularly annoying for me, because I haven't got access to a changing bag at the moment (my partner has one but is currently off with it in the US). Instead I took a normal backpack into the little cubby under the stairs and used that as a makeshift darkroom (with the bag as extra protection against any light that might have sept under the doors; I don't know if this will have offered enough protection, but some of the light seals on the back I'm using look like they might be rotting, so if there are leaks I won't know their provenance with certainty) and then rewound the film back into the can by hand.
Some improvements for my next roll: I reckon cutting the paper leader to 43 cm will include frame X0 or 00 or something like that on the emulsion, so for my next attempt I might cut the paper leader even shorter down to 40 cm. That feels like a lot of wasted emulsion if 43cm is enough, so I want to see the developed negatives before I run my next roll. Also, I plan to actually cut a little bit further than the arrow, to account for the half turn (okay, it's more like 160°, which is something like 2.8 cm) that the canister has to take to be seated properly in the back, and next time I'm going to secure the film to the paper leader using regular clear tape, which I think is thinner. For this first attempt I was just using masking tape because it's super quick and easy to work with, but you can really feel when it's passing through the flocking.
I need to make a mask for focusing screen. So far I've measured a distance of 12 mm on either side of a strip film in the... exposure area (I swear it has a name but it escapes me at this moment)? Anyway, making for a total height of 59 mm within expectations, so the film takes up 59.3% of the exposed area and 40.7% without sprocket holes. These percentages might be important because it seems the ground glass (65 mm actual size by 55 mm guide lines) isn't 1:1 with the film area (67 mm long axis by 59 mm short axis; the one that matters), but I'm not sure if what you see on the focusing screen is exactly what will be in frame. Either the focusing screen is cutting stuff off or it's slightly resizing what you see (or both). I could make one out of paper but it seems awfully annoying to have to take the viewfinder off to change orientation or to switch back to MF, so I haven't made it yet. I want to build something a bit more sturdy and unobtrusive. I think I'll pick up a sheet of acetate and just write on it with a small texta and that should do the trick for a quick and easy job.
Anyway my apologies if this has gotten a bit rambly. I tried to keep my writing as focused as I could but sometimes it's hard for me to actually tell whether or not something I've said is a tangent. I will post more to this thread as I make further progress on this stuff, and hopefully with some scans soon. When I get this worked out more I think I'll also take some step by step photos or maybe even record a video guide. Cheers
I think you could also use the sprocket holes for deliberate artistic effect although I don't think I've seen too much of this. I don't know how I'd do it myself.
16mm film (Kodak TriX/ D76 1+1 12')+ RZ67 50mm lens