Say what?
If this is a Rollex roll back (knob wind) it is obsolete. If it is a Super Rollex (lever wind) then what vitage? Some of these are so old there are no repair parts any longer.
Say what?
If this is a Rollex roll back (knob wind) it is obsolete. If it is a Super Rollex (lever wind) then what vitage? Some of these are so old there are no repair parts any longer.
Thanks for the confirmation, Bob.
I made a deal with the seller for a partial refund in the end.
I also tested with T-Max 400, running a test roll through and marking the frame lines in daylight, and it looks like it should work. Since some people said that Ilford films worked for them, I glanced through some technical data sheets to get some numbers on base thickness:
T-Max=4.7 mil
Ilford rollfilms=4.3 mil
Efke rollfilms=4 mil
Fuji transparency films=4 mil
New Tri-X and Kodak transparency films=3.9 mil
Old TX and TXP (what I used to test the back originally)=3.6 mil
Current Ilford data sheets for FP4+, HP5+ and 100 Delta (I can't get the 400 Delta .pdf to load at the moment) indicate 4 mil rollfilm bases, not 4.3 mil.
It's more ambiguous than that, actually. They say .110mm=4 mil (which it doesn't) on some sheets and ".110mm" on others. I suspect the .110 mm is the more accurate figure, since they cite it more often, and maybe they regard that nominally as "4 mil". Either that or there's a wider tolerance to these numbers than the figures might lead us to believe. 1 mil = 0.001 of an inch = 0.0254 mm.
Anyone with a micrometer calipers and a fixed roll of HP5+?
Actually doing the division for 35mm, rollfilm and sheets, it seems Ilford rounds off from a precise metric measurement to the nearest whole mil. Caliper measurement will have to wait until this evening when I can access some developed film and the instrument.
Just another thought. On my next roll through my holder I am going to try advancing the film about an inch or two past the arrow. This will make the roll thicker before the counter starts. Given that it tends to bunch the spacing there is plenty of space left at the end, even if the frames are no longer touching.
Larry, if that works, it would be a real solution. Alternately, I was thinking that instead of putting masking tape on the spools, it would be much easier and neater to put a couple of strips of masking tape across the backing paper at the beginning of the roll to get a little more bulk.
David, I sacrificed a roll of Velia to test it. I first ran the roll through with the start arrow set in the window/slot - you know what I am talking about. Marking the frames with a marker showed most were overlapped or touching. I then rewound the roll - I don't think this could mess it up because the counter works off the takeup spool. I then tried it with turning the takeup spool exactly one extra turn - I marked the silver wheel with a marker for this. I then marked the fames again and there was about 1 to 2mm between all frames and I had about an inch and half of extra film at the end of the roll. I think I would call this a very workable solution for my 6x9 back. I suspect it may work for your 6x6 as well. Maybe try 3/4 or 1/2 if you run out of film.
Not a bad result! Thanks for trying it out. I'll have to try shooting a roll of RMS (base thickness .098mm like Velvia--closer to 4 mil than Ilford--I have lots in the freezer) with an extra revolution or two past the arrow sometime soon and report back.
Something I haven't thought about is the thickness of the backing paper. There are quite a few revolutions wound onto the spool at the beginning and end of the roll, and I don't know whether that has gotten thinner over the years.
Another interesting thing I've observed is that other MF cameras I have of similar or older vintage like the Voigtlander Perkeo II (circa 1956) or Voigtlander Superb TLR (1933-38), managed to design a frame counter with a feeler wheel, so the thickness of the film doesn't matter.
OK, here's a measurement update.
My Mitutoyo digital caliper reads only to the nearest 0.01 mm. Therefore, when selecting 'inches' for display, it shows four digits after the decimal point but jumps in .0005 (0.5 mil) increments. Given that resolution limit, here are some readings just taken of the clear area of 120 films developed in Microdol-X (except where noted), fixed and washed:
100 Delta: 4.5 mil
FP4+ (PMK): 5.0 mil
Delta 400: 5.0 mil
100 TMX: 5.5 mil
Acros: 4.5 mil
I guess emulsion plus any gelatin back- and/or overcoat add to base thickness; data sheets only specify the base. In summary: these are not data for a scientific treatise, but hopefully an interesting anecdote anyway.
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