Need more help getting even lomo tank processing.

[slashmaster]

I processed another black and white negative 100 ft roll in 3 sections. When I play them they are all very consistent on the left side of the screen but not so consistent on the right. This is very noticeable in the sky. Trying to figure out what I did wrong. I put them on the lomo tank reel directly from the camera takeup reel emulsion side out. That means the soundtrack side must have been up (even though it was double perf) and the normal sprocket side down right? I was using 1.5 liter bottles of developer and fixer almost full, maybe I poured the developer in too slowly but it splashed so some of the film developed longer as it filled up? Maybe I should fill the tank in the dark first then dip in the lomo reel? I tipped the tank toward its hose as I drained it back into its bottle. Was this a bad move?

[aj]

It is a 10 meter LOMO?

By the description I would say you have a agitation procedure which gives uneven up en down processing. The spiral groove is only at the bottom side. Don't you get marks around the perforation?

Development time shouldn't be too short. The shorter the more influence filling and draining have.

Starting with a filled tank is a good idea.

I always put a drop of wetting agent in the developer and poured it in through the hose using a funnel. Takes only some 10 seconds for 600ml in a 15 meter LOMO with one deck of super-8. The spiral agitates itself when pouring in. After that rotate the spiral once per minute (on 10 min of development). Also rock the hub while rotating. This will stir the low and top layer of the fluid.

[Angus]

I haven't used my 10m Lomo tank for a while, maybe 6 years, but I do not recall having uneven results. My only advice would be to choose chemicals that require at least 10 minutes developing time (dilute if necessary) as any time taken filling and emptying the tank will be less significant.

It is possible to get very good results even with the older Lomo tanks, I've done B&W reversal and E6 with results almost as good as the professionals.

[carllooper]

It is apparently a well known effect when processing B&W neg in a Lomo.

It doesn't happen with colour or B&W reversal

B&W neg, it would seem, is particularly sensitive to the geometry of the Lomo spiral - in particular the radial arms. The variation in density of the result appears to correlate with the radial arms of the spiral. A technique requiring some experimentation to get right, is to loosen the top spiral (disc?) and gently alter it's orientation throughout the development process. You will want the perf edge of the film facing down because that edge can't be rotated with respect to the radial arms on the bottom spiral and the perf edge presents less of the image area to such.

C

[slashmaster]

Thanks for the replies guys!

AJ, Angus, this is a 15 meter tank. The reason I did it 1/3 at a time is because this reel had a bit over 100 ft. Now that it's processed and has a leader it barely fits on that reel. I did dilute the developer to 1/2 strength and processed about 12 minutes. Every 30 seconds I had been jiggling for a second, turning 90 degrees and jiggling another second. I only turned it clockwise. AJ I've never tried pouring the developer through a funnel through the hose. Do you also do that with the fix?

Carl, I didn't use the other spiral as the top but used the more open disc. Maybe it correlates to the arms on that? Since this affects black and white negative film most, does it affect tri-x processed as negative? So you're telling me to take the cover off in the dark while processing so I can loosen the knob and rotate the disc a few degrees a few times during processing?

[aj]

. AJ I've never tried pouring the developer through a funnel through the hose. Do you also do that with the fix?

I pour in and drain all baths and water through the hose. Use a big funnel with a big opening which just fits the hose. Keep the hose free of locks Hold the funnel up to let gravity help with pulling the fluid in. The same for draining but then hold the hose low. I keep the tank put as it is clumsy and too costly to let it break should it drop.

[carllooper]

Carl, I didn't use the other spiral as the top but used the more open disc. Maybe it correlates to the arms on that? Since this affects black and white negative film most, does it affect tri-x processed as negative? So you're telling me to take the cover off in the dark while processing so I can loosen the knob and rotate the disc a few degrees a few times during processing?

I haven't used this technique myself (haven't processed B&W neg) but this is the technique that those at our lab, who do process B&W neg, use. We had a workshop about it, looking at the effect when neg is processed 'normally' and the alternative technique (of which there may be others). And yes, the technique is as you've described. Not sure about reversal processed as neg. My understanding is that it's only B&W neg stock that has this issue. And yes, I meant to say the top "disc" rather than top "spiral" - the radial arms on such.

It's no doubt got something to do with the radial arms acting as a trap of sorts during agitation. The purpose of agitation is to redistribute the chemistry during development, and this should ideally be everywhere the same. From the effect I'm assuming chemistry for B&W neg is overly sensitive to a variation in surface tension between the chemistry and the plastic of the spiral - which I'm speculating introduces inconsistencies in the redistribution of the chemistry - resulting in the effect of a variation in density that correlates with the radial arms - a repeating pattern of variation increasing in rate towards the centre of the spiral, ie. as the arms converge on the centre.

The difference in density of the resulting film itself is really quite small, and would be completely irrelevant for individual frames, but it's the variation in such (between frames) which becomes visible in motion picture work, and can be a bit annoying.

From a philosophical point of view there is a position in experimental film theory, of a traditional materialist persuasion, in which individual frames can be considered as more 'real' than the duration/movement in which such frames are otherwise constituted, and so the variation in density between frames could be ignored or otherwise exploited to make more visible the material nature of film. Myself I take a different position, treating the relationship between frames (motion and duration) as more 'real' than any particular frame considered on it's own. I may very well be more of an anti-materialist in this way. But I'd probably argue for a different kind of materialism in which materials are understood in terms of a temporal (and magical) dimension, as much as a spatial one. In any case this alternative position could also support treatment of the density variation as an exploitable feature. Not that I would personally pursue that myself.

C

[Mmechanic]

Spirals in closely nesting tanks and pouring solutions in has always seemed meagre to me. As soon as you want reliably repeatable and uniform development you prepare larger baths. Keep that spiral in constant movement in cheap plastic troughs.

I only have perfect results with a JOBO hundred-foot reel in ten liter baths. I have no problems working in the dark. The troughs on tables, rubber gloves, a darkroom timer near the first three baths, my holy grail of labour.

Orwo-P.-F.-2-Verläufe, 23.jpg

[slashmaster]

Thanks AJ, I'm going to try the funnel method tonight if I can find an appropriate one before I process. Doesn't this leave inconsistencies at the part of the film where it comes in from the hose?


Thanks Carl, so you think the plastic itself causes problems? Wonder if one made of steel or aluminum would help. By the way, you have any films you made with your stepper driven bolex? If so how is the registration? Seems my bolex gets better registration at 8 fps than 24, was hoping going even slower with a stepper would bring even better registration but the buzzing of the motor seems to hurt it.

Thanks Mmechanic! So you're saying have a trough for each bath to dip the lomo spiral in? I did fill a container with water that I would dip the whole lomo tank in. Have you ever had problems with a little light from something you weren't expecting? Like maybe a plastic shower curtain that glows in the dark a little? Or duct tape giving off light when you peal it! I didn't even know duct tape gave off light when you pulled it off it's roll. I wonder if it did any damage to my film..

MAYBE I SHOULD TRY THIS FUNNEL METHOD AT MY GIRLFRIENDS HOUSE

[carllooper]

Thanks Carl, so you think the plastic itself causes problems? Wonder if one made of steel or aluminum would help. By the way, you have any films you made with your stepper driven bolex? If so how is the registration? Seems my bolex gets better registration at 8 fps than 24, was hoping going even slower with a stepper would bring even better registration but the buzzing of the motor seems to hurt it.

I don't know if it's to do with it being plastic. Perhaps it is?

I haven't had any registration issues with the Bolex but then I've only ever done slow speed turn over where the per frame exposure time is anything between quarter of a second to a number of seconds - in other words slower than 2 frames per second! I guess at this rate there couldn't be any registration issues as there would be next to no residual momentum in the film transport to produce such. Not that this was the reason for doing a slow turn over - it was to do with a not very bright light source, and otherwise preferring an aperture of around f/5.6 to f/8. But if the slow frame rate also helps registration that's a bonus.

A stepper can other wise fail to rotate if you're pulse rate is too high. And this might cause vibration. One has to test the stepper against the load it's trying to overcome - and this will be different for different rates at which it is otherwise being pulsed. For example, you can get a stepper up to very high speed if you increase the rate slowly up to that speed. But if you were to otherwise try and get it up to a certain speed quickly it can stall. If it's otherwise stalling/vibrating at a slow rate (where it's otherwise okay at a faster rate) it will be due to some design fault in the controller/software, where it's fighting itself for where it should be sitting.

If you are having registration issues with the Bolex, I'd just check the pressure plate is okay. Are the springs on the plate applying enough pressure? Is the pressure plate actually closed? When the film is pulled down by the claw the film should ideally come to a stop in the same position each time - and the pressure plate should stop it from doing otherwise - but at a fast rate the film might otherwise find itself landing in ever so slightly different locations on each pull down - normally it wouldn't matter but if doing effects work, for example involving double exposure, one might prefer even just the slightest difference in film positioning to be eliminated. Pin-registered cameras would have no reason for existing if there wasn't some sort of tiny difference in registration possible (on a conventional camera).

With the stepper motor I just get it do one complete cycle over a given interval, where the interval is a function of the desired exposure time and the shutter angle. Originally I had it open the shutter as fast as possible - and then stay put for a specified interval - and then close the shutter as fast as possible. But it was a lot simpler to just have it turn 360 degrees over a precomputed interval. Once the shutter reaches a closed position it then waits until the projector frame is advanced (itself stepper motor driven) before repeating the turn over.

There are films that have included work done on the printer but none that I know of that have been copied to video.

C

[doug]

If you are having registration issues with the Bolex, I'd just check the pressure plate is okay. Are the springs on the plate applying enough pressure? Is the pressure plate actually closed? When the film is pulled down by the claw the film should ideally come to a stop in the same position each time - and the pressure plate should stop it from doing otherwise - but at a fast rate the film might otherwise find itself landing in ever so slightly different locations on each pull down - normally it wouldn't matter but if doing effects work, for example involving double exposure, one might prefer even just the slightest difference in film positioning to be eliminated. Pin-registered cameras would have no reason for existing if there wasn't some sort of tiny difference in registration possible (on a conventional camera).



C

I'm no expert on Bolex, but in my experience the pressure plate doesn't appear to affect the registration by the claw, at least in a properly serviced camera. In fact sometimes I've run taken, known rock-steady, footage through the camera with a light behind the gate, just to check registration, ie. without pressure plate at all. I would think the plate is only there to keep the film flat during exposure.
But this is getting rather away from lomo tanks

[carllooper]

I'm no expert on Bolex, but in my experience the pressure plate doesn't appear to affect the registration by the claw, at least in a properly serviced camera. In fact sometimes I've run taken, known rock-steady, footage through the camera with a light behind the gate, just to check registration, ie. without pressure plate at all. I would think the plate is only there to keep the film flat during exposure.

Yes, I don't know what would otherwise cause registration issues. The pressure plate is certainly to keep the film flat, but in doing that job it would also help to stop the film from continuing to move after the claw has stopped/retracted, which the film would otherwise want to do (according to Newton's first law of motion). The way the film is looped also provides braking pressure on the lens side, although not as much as the pressure plate. The faster the film is transported the greater will be any such vagaries in positioning.

But we're talking about very tiny differences in positioning here - which can normally be completely ignored, as you wouldn't otherwise notice them at all. The only reason one might want to obtain more precise registration is when doing effects work, such as those involving double exposures, where the separate passes need to stay in register with each other. For even the slightest difference in positioning between the passes become noticeable. It's one of the reasons why pin-registered cameras were invented.

C

[aj]

Thanks AJ, I'm going to try the funnel method tonight if I can find an appropriate one before I process. Doesn't this leave inconsistencies at the part of the film where it comes in from the hose?

Any luck? The spiral starts rotating by itself when the fluid enters the tank. No single spot is exposed to the incoming jet of fluid.

The main trick is to let gravity cooperate Hold the hose/funnel high when filling and hold it low when draining. You can clearly hear the suctionforce from the fluid cascading down

I toss in 600ml for one deck of super-8 and use 3 times of 1 litre of water for the inbetween washes.

I know from my 35mm still processing that Paterson spirals are somewhat more prone to producing uneven development around the perforations. Never seen anything like that on Jobo spirals. What could possibly be the difference on such a simple concepts. Just don''t rotate that much. Only short periods at intervals.

[slashmaster]

Thanks Carl! I know this camera normally gets very good registration for a non pin registered camera, especially at 8 fps. I think I set the driver to 1/4 microstep so it really jitters at 1 fps or less. I think that was my mistake Going to try it at 1/32 for my next film. Already turned the amperage and voltage as low as it goes.

Thanks AJ! Was just about to try it. I had been slightly crushing the end of the bottle so there would not be so much air in it when I put the cap on. I popped out the dent and added more water because I thought maybe the level was not going high enough in the tank and now all the crust that was on the wall of the bottle floating around in the developer. Hmmmmmmm, should I filter it through a sponge? Are these little pieces of crust what causes all the little white spots on the film?

Thanks Doug, I'm pretty sure the pressure plate does make a difference. But mine seems good and I have 3 to choose from.

[slashmaster]

Just put it up to dry and it did not come out good It has a sticky substance all over it and the contrast is poor. I'm guessing because of the mess I made when all the flakes came off the wall of the bottle? The funnel had just a little bit of transmission fluid and oil residue on it. Was trying to clean it as best I could but never got it 100% clean. It wouldn't mess it up this bad would it? Probably not even a drop worth of transmission fluid?