Tonight I decided to take a close look at my Jobo reels and try and figure out why I have been unable to load a 120 film on them. I started by cutting a piece of 120 backing paper to length and used that as a substitute for film, and tried loading in room light.
On my first try the paper would only load about 2 wraps and would go no further. What had happened was there is a small piece of the plastic that has broken where the red tab snaps to allow for loading a 220 film or two 120 films. The edge of the film would drop out of it's track toward the centre of the reel due to it's natural curl and jam. My reels came with my processor which I bought used, and half of my reels were broken. I believe that any breakage condems the reel to scrap.
After finding an unbroken reel, I tried again to load it with paper. The paper would start, but once it was about half way on, it was getting more and more difficult to advance, and I started to hear (and see) the familiar crunching sound I have experienced before of film buckling and creasing. The paper was essentially stuck, and I was unable to move it any further.
After a close inspection, I found that the inner portion of the reel where the film goes is slightly too narrow for a 120, there was absolutely no edge to edge clearance. When a small amount of film is on the reel, there is enough wobble to allow the reel halves to move slightly to allow some clearance, but as more film is put on, this wobble disappears and the film is wedged in place.
Next, dug out my calipers and started measuring. I first measured the width of a piece of Ilford HP5 and it is 2.410". Then I measured the backing paper, and it was 2.460", or 0.050" wider than the film, as expected. Next I measured the inside track of the reel, and it came to 2.396", or 0.014" (0.36mm) narrower than the width of the film. This measurement confirms my experience of being unable to load a complete 120 onto the reel due to binding. In comparison, the film track width of a Paterson reel is 2.435", or 0.025" wider then the film. This probably explains why I have always been able to load a Paterson reel with ease, it's wider than the film; so there is some clearance for the film to move side to side.
My solution was it use a cut off wheel in my dremel tool and to slightly cut some material off of the locking pegs on the inside if the reel, to allow it to move outward slightly. This makes the track for the film wider, and I was able to load the paper entirely once I had made this modification. I eyeballed how much to take off, and it ended up widening the reel by about 0.020", so now the track is at least the width of the film. I was able to load the backing paper successfully in the dark. However, I find that it is still much easier to crease and/or buckle the film than loading a Paterson reel. In the second photo the cut mark is visible at the bottom of the centre portion.
So for the 120 position anyway, a Jobo 2500 reel requires modification to be successfully used. I have not measured the 35mm position, but I have had similar troubles loading 35mm in the past.
On my first try the paper would only load about 2 wraps and would go no further. What had happened was there is a small piece of the plastic that has broken where the red tab snaps to allow for loading a 220 film or two 120 films. The edge of the film would drop out of it's track toward the centre of the reel due to it's natural curl and jam. My reels came with my processor which I bought used, and half of my reels were broken. I believe that any breakage condems the reel to scrap.
After finding an unbroken reel, I tried again to load it with paper. The paper would start, but once it was about half way on, it was getting more and more difficult to advance, and I started to hear (and see) the familiar crunching sound I have experienced before of film buckling and creasing. The paper was essentially stuck, and I was unable to move it any further.
After a close inspection, I found that the inner portion of the reel where the film goes is slightly too narrow for a 120, there was absolutely no edge to edge clearance. When a small amount of film is on the reel, there is enough wobble to allow the reel halves to move slightly to allow some clearance, but as more film is put on, this wobble disappears and the film is wedged in place.
Next, dug out my calipers and started measuring. I first measured the width of a piece of Ilford HP5 and it is 2.410". Then I measured the backing paper, and it was 2.460", or 0.050" wider than the film, as expected. Next I measured the inside track of the reel, and it came to 2.396", or 0.014" (0.36mm) narrower than the width of the film. This measurement confirms my experience of being unable to load a complete 120 onto the reel due to binding. In comparison, the film track width of a Paterson reel is 2.435", or 0.025" wider then the film. This probably explains why I have always been able to load a Paterson reel with ease, it's wider than the film; so there is some clearance for the film to move side to side.
My solution was it use a cut off wheel in my dremel tool and to slightly cut some material off of the locking pegs on the inside if the reel, to allow it to move outward slightly. This makes the track for the film wider, and I was able to load the paper entirely once I had made this modification. I eyeballed how much to take off, and it ended up widening the reel by about 0.020", so now the track is at least the width of the film. I was able to load the backing paper successfully in the dark. However, I find that it is still much easier to crease and/or buckle the film than loading a Paterson reel. In the second photo the cut mark is visible at the bottom of the centre portion.
So for the 120 position anyway, a Jobo 2500 reel requires modification to be successfully used. I have not measured the 35mm position, but I have had similar troubles loading 35mm in the past.
