OP
OP
Gavjenks
TPF Noob!
- Joined
- May 9, 2013
- Messages
- 2,976
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- 588
- Location
- Iowa City, IA
- Can others edit my Photos
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Update!
So i finally got some 4x5 in the mail to experiment with. Results so far from strips cut from a test sheet:
Wrapping the film around a 1/8" tube --> film kinks into distinct angled kinks
Wrapping the film around a 1/4" tube (bic pen) --> when unrolled, it curls so much that when placed on a flat surface, it curls around and back over (>180 degrees). Obvious film damage can be seen with the naked eye.
Wrapping the film around a 3/4" tube (highlighter) --> when unrolled, on a flat surface, both edges rise up about 10mm from the table surface. Not good for taking a flat photo even if held in place on both edges I'm guessing, probably damaging the film a little.
Wrapping the film around a 1 1/4" tube (dowel rod I have lying around - this was my planned roller diameter) --> when unrolled, on a flat surface, both edges rise up about 2.5mm from the table surface. Looks quite possible to flatten without much difficulty. Certainly if using an air pressure system, and probably with edge guides. I doubt the film is significantly damaged, but before making a camera, I will take some shots with pre-rolled film in a simple pinhole setup and develop them to look for stress lines or anything like that (will post here about it).
Wrapping around a 1 5/8" PVC tube --> 1.5mm of rise on each side when unrolled.
Original rolls were for a minute or two. After an hour of being taped in place again, the 1 1/4" roll now rises 5mm when unrolled. And the 1 5/8" tube now rises to about 2.5mm.
I still have them back on the rolls now, and will check again tomorrow.
Connection:
Heat fusing was not so successful. However, I was simply using a homemade heated piece of angle metal heated in a stove, not anything like what I would actually use. Just wanted to see if it was trivially doable. It is not. Temperature needs to be much more exact (either nothing happens or it starts working but then bursts into flames for a fraction of a second then vaporizes over a range of about 50 degrees), so I need to ideally find a friend who has one of those bag sealers with even, controllable heat along the whole length, because I don't want to drop $100 on one just to find out it doesn't work. Might work just fine with the correct tool. If so, I think I could get actually MORE usable film space than with a traditional holder, since it only needs to be fused on two ends, not the long ends. (4x4.75 or so instead of 3.75x4.75 or whatever)
Unexpectedly, stapling actually works pretty well, lol!! As long as the staple runs perpendicular to the direction of rolling (which I could do in a jig using this Cool Tools ? Mini Booklet Stapler ). It only distorts about 1/4" of film around the staple in either direction, so 4"x4" of the film would be unaffected, possibly 4.25" x 4" if I can get precision lining up (this represents 15% of film surface lost, versus about 8% lost in a traditional film holder). The piece of polyester it is attached to seems to effectively stop any scratching of other sheets of film top or bottom, at least to the naked eye. I will also test this with a couple test sheets in a pinhole box before building anything serious of course. There may be microscopic scratching, or it may locally increase the radius of curvature of the sheet above it too much. One problem here is that i can't make it so that exactly 1 or 1.5 turns or whatever always = one shot. I have to make it an odd amount, like 1.37 turns, so that staples dont all line up on top of one another and make the roll wonky shaped. But that's not so bad if the top of the roller is marked off with hash marks and there's an indicator on the top of the camera so you can do 1.37 turns without thinking.
Also considering thread, if I can come up with a way of doing it in a jig in the dark easily.
Blerh... really hoping the heat method works with the right tool, though, cause these other ideas are pretty hackish. Might come up with something elegant though. Back to drawing board.
So i finally got some 4x5 in the mail to experiment with. Results so far from strips cut from a test sheet:
Wrapping the film around a 1/8" tube --> film kinks into distinct angled kinks
Wrapping the film around a 1/4" tube (bic pen) --> when unrolled, it curls so much that when placed on a flat surface, it curls around and back over (>180 degrees). Obvious film damage can be seen with the naked eye.
Wrapping the film around a 3/4" tube (highlighter) --> when unrolled, on a flat surface, both edges rise up about 10mm from the table surface. Not good for taking a flat photo even if held in place on both edges I'm guessing, probably damaging the film a little.
Wrapping the film around a 1 1/4" tube (dowel rod I have lying around - this was my planned roller diameter) --> when unrolled, on a flat surface, both edges rise up about 2.5mm from the table surface. Looks quite possible to flatten without much difficulty. Certainly if using an air pressure system, and probably with edge guides. I doubt the film is significantly damaged, but before making a camera, I will take some shots with pre-rolled film in a simple pinhole setup and develop them to look for stress lines or anything like that (will post here about it).
Wrapping around a 1 5/8" PVC tube --> 1.5mm of rise on each side when unrolled.
Original rolls were for a minute or two. After an hour of being taped in place again, the 1 1/4" roll now rises 5mm when unrolled. And the 1 5/8" tube now rises to about 2.5mm.
I still have them back on the rolls now, and will check again tomorrow.
Connection:
Heat fusing was not so successful. However, I was simply using a homemade heated piece of angle metal heated in a stove, not anything like what I would actually use. Just wanted to see if it was trivially doable. It is not. Temperature needs to be much more exact (either nothing happens or it starts working but then bursts into flames for a fraction of a second then vaporizes over a range of about 50 degrees), so I need to ideally find a friend who has one of those bag sealers with even, controllable heat along the whole length, because I don't want to drop $100 on one just to find out it doesn't work. Might work just fine with the correct tool. If so, I think I could get actually MORE usable film space than with a traditional holder, since it only needs to be fused on two ends, not the long ends. (4x4.75 or so instead of 3.75x4.75 or whatever)
Unexpectedly, stapling actually works pretty well, lol!! As long as the staple runs perpendicular to the direction of rolling (which I could do in a jig using this Cool Tools ? Mini Booklet Stapler ). It only distorts about 1/4" of film around the staple in either direction, so 4"x4" of the film would be unaffected, possibly 4.25" x 4" if I can get precision lining up (this represents 15% of film surface lost, versus about 8% lost in a traditional film holder). The piece of polyester it is attached to seems to effectively stop any scratching of other sheets of film top or bottom, at least to the naked eye. I will also test this with a couple test sheets in a pinhole box before building anything serious of course. There may be microscopic scratching, or it may locally increase the radius of curvature of the sheet above it too much. One problem here is that i can't make it so that exactly 1 or 1.5 turns or whatever always = one shot. I have to make it an odd amount, like 1.37 turns, so that staples dont all line up on top of one another and make the roll wonky shaped. But that's not so bad if the top of the roller is marked off with hash marks and there's an indicator on the top of the camera so you can do 1.37 turns without thinking.
Also considering thread, if I can come up with a way of doing it in a jig in the dark easily.
Blerh... really hoping the heat method works with the right tool, though, cause these other ideas are pretty hackish. Might come up with something elegant though. Back to drawing board.
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