rotation, rotary, tilting, inversing -agitations. Facts and Myths?

[Usagi]

Yes, again question that has haunted me a long time.

Usually with the normal developing tank you got the lid and the stick that should be used for rotating the reel (spiral) in during the agitation.

Most sources that I have read says that the stick should throw away immediately as it's do only harm to your firlms. The rotatin agitation with stick is bad. The film's speed at the outer edge of spiral/reel is faster than inner. So the the deeper the film is in the spiral, the less it develops.

1. Point for question: Is that really that straightforward? Have anyone done or access to test and results where two identical films are exposed with middle gray and another developed with using agitation and another with only using rotary stick.

Is there remarkable difference in the density of the film frames that has been on the outer area of the spiral?


2. question follows directly: If the result was what most would expect, the edge area of film was more dense. Then how could rotary film processer be so popular and famous of the even quality that they gave.

What is changed when compared to table top tank where film is rotated by rotary stick?
- outer edge has faster flow in the chemistry, same for both
- inner parts has slower flow... Again same for both
* In the rotary stick rotation, the reel/spiral is always under the chemistry. In the rotary processor, the film breaks the surface of chemical twice. First when rising up from the chemical and second time when diving to the chemical again.

The last point is the only difference I can Imagine.


3. The lifting method. This method has said to be best for roll films. It has to done in complete darkness and the lid of the tank is left open.
First dump developer to the tank, then lift reel(s) to the tank using special rod and then do agitation by lifting reels form the tank, rotating them something like 60 degrees and raise them again back to the tank.

Much more troublesome than more common shaking/inverting agitation but results should be really good. Or is it? Being bit sceptic here.



I know that there's lot of other members on the board that has done tons of tests but does anyone tested this? rotary agitation (jobo stylish), normal inversion agiation and then rotary agitation by using rotary stick/rod.

Which will gave the most even result and why? Is that repeadable?

The differences should be clear with 120 film if they exists. If there's no differences then at least some of the thousands 'hard to kill' myth that lies beneath the thin surface of the B&W developing world is busted.

 

[Anscojohn]

Hallo Jukka,

I was taught (almost 50 years ago) that when using the twirling stick, to gently move the film back and forth several times. I am sure that if one spins the reel like a croupier spins the wheel, the phenomenon you describe might take place. Be gentle.

Raising and lowering is something I do, but not with small tanks. I sometimes do this with a gallon tank of developer. I remember reading about the darkroom technique of one well-known photographer of a past generation who raised and lowered his film in 1/4 inch increments.
When I am souping a lot of film strung on rods, I just use a variation of the ASA method suggested for sheet film.
Most of the time, I just use invertable SS tanks. I invert gently, two or three times, so the reels click against the top of the tank with somewhat less a metallic sound than opening a can of soda.
And, no I have not done any stringent tests. One of these days I should get around to it, I guess.

 

[Diapositivo]

The film's speed at the outer edge of spiral/reel is faster than inner. So the the deeper the film is in the spiral, the less it develops.

Maybe the reason why results are good is simply that at the outer edge the speed is faster, but there also is "more film" to develop (the same quantity of chemistry is applied to a larger surface of film).

So the development, which depends from the relation (film surface / chemistry volume) is even.

Just my fast mumbling on the subject.

Cheers
Diapositivo

 

[DanielStone]

Use what YOU'RE comfortable with. Whether its with the twirly-stick, or inverting on your cycle(end over end), its up to you and YOUR needs.

personally, my method is to agitate continuously for the first 30s, then for 5s at 30s intervals. I do it like this:

1. Invert(end over end) 2x
2. twist tank 90deg(1/4 turn) 2x
3. tap against counter 2x

works for me, never a problem.

-Dan

 

[Usagi]

Maybe the reason why results are good is simply that at the outer edge the speed is faster, but there also is "more film" to develop (the same quantity of chemistry is applied to a larger surface of film).

So the development, which depends from the relation (film surface / chemistry volume) is even.

That could be one factor.

This is really interesting issue as I haven't never seen any real world tests, only hear or read 'rumours'.

If the continuous rotation system gives better result than using twirling stick then the reason would be nice to know.

Perhaps I should sacrifice some rolls of film and do test by myself.

One roll with continuous rotary, one with normal agitation pattern and one with twirling stick.

 

[Anscojohn]

I think a count of complaints and requests for help with rotary processors compared to the postings about development problems with hand tanks would indicate far more problems encountered with rotary processors. Of course, it may just be that more people use rotary tanks than not.

Back in ye oldene dayz I hand developed Anscohrome in a small Ansco tank with a twirling stick that included a thermometer. I never relied on the thermometer, but the Anscochrome seemed to turn out o.k. Ansco even made the reel with one clear plastic side so that the light from the reversal exposure to a photoflood would hit all the film better. I guess if they relied on a twirled hand-tank for a color process, it must have been o.k.

 

[WolfTales]

"The twirling stick" - for some reason it reminded me of the "apparatus" during the Olympics when they got the ribbons and batons going

 

[erikg]

I think a count of complaints and requests for help with rotary processors compared to the postings about development problems with hand tanks would indicate far more problems encountered with rotary processors. Of course, it may just be that more people use rotary tanks than not.

Interesting...my guess would be the opposite, but then I seem to notice more issues and troubles with stand development... rotary machines are great until a problem crops up and then it can be very vexing. With tanks it seems easier to isolate the cause of trouble if it is encountered. All of these methods has been shown to work, best to be consistent with what ever you do.

 

[Martin Aislabie]

I can only give you my experience and with no scientific measurements - but - I have never seen any differences between twirling the Paterson Stick and inverting a Paterson and/or Jobo Tank.

I also have not noticed any differences in film development between the inner and outer ends of rolls of film with either stick twirling or inversion

I have not tried lifting rolls of film loaded on spools out of the developer - I only do this for sheet film.

I don’t do so much roll film any more but when I did I would happily substitute twirling the Paterson stick for Tank Inversion. I would sometimes choose Stick Twirling on a Paterson Tank to minimise the exposure of my hands to Developer (which always seems to seep out of my Paterson Tanks) if I had lots of rolls of film to process.

Afterwards I could not tell which roll of film had been in a Jobo Tank, a Paterson Tank using inversion agitation or a Paterson Tank with twirling agitation.

Personally, I have always considered the horror stories of twirling agitation to be the stuff of photographic urban legends – so look forward to see the scientific “proof”

However, I doubt such well established old wives takes can be laid to rest very easily

Martin

 

[Anscojohn]

Martin,
The poster who suggested that the greater angular velocity of the outer parts of the reel might be compensated for by the lesser film area toward the core of the reel makes sense to me.
As I said, if doing color Anscochrome in an ansco tank with a twirler is not a problem, I cannot see b/w being a problem.
Regarding another poster's comments that it seemed there were more problems with stand development than anything else, I am not allowed to comment upon that. Sandy King won't let me....(VBG)

 

[Ed Sukach]

JOBO addressed this idea - that the film on the innermost area of the reel has a greater velocity during rotation, and there was a possiblity of uneven developmet.

After beating this to DEATH (and I mean THRASHING it..), and extensive statistical analyses of the results - *NO* difference between "inner" and "outer" developed film - with ANY film/ developer combination.

NADA!!!.

So .... moving on...

 

[Ronald Moravec]

The Patterson stwist stick is for the initial agitation only per their instructions.

Rotary processing works because the film is rolled thru the developer and then into air as the tanks are less than half full. Doing this in the other plane with a twist stick and with a full tank causes more spent developer to be replaced on the edges compared to the center. Then the edges get more density than the center where the used developer does not get replaced sufficiently. Slow rotation and depending on incomplete & even replacement is asking for trouble. Raising and twisting avoids incomplete replacement in the center.

Patterson tanks can be inverted with good replacement because there is lots of empty space in the lid.
Smaller tanks can be inverted 5/7 time or use a twist and invert twice. You can also use a two reel tank with film on the bottom only and half full. Invert twice and all the developer leaves the film and goes back down. Works perfectly. You can also roll the said tank for 1.5 revolutions and then upright to rest between cycles of agitation so the film is completely covered. Bill Pierce wrote this up in Modern Photography in 196x and it still works fine. Remember 8 oz developer in 16 oz tank but cover the film when at rest.

Remenber THERE IS NO SUCH THING AS SURGE MARKS OR FLOW MARKS. All marks are a result of insufficient or incomplete or NONRANDOM agitation so some parts of the film do not get replenished. This is most noticable if it happens in the first 60 sec but can happen anytime. FULL COMPLETE and RANDOM agitation is the key. Gentle schemes only try to get even incomplete replenishment and you have little chance of getting it right.

The other principle is the wet dry edge must start and proceed RAPIDLY across the film without backtracking
on the initial agitation.

That is why you should not pour developer into a stainless tank. Drop the loaded reel(s) into to full tank of developer. You can almost always "get away" doing it with a single reel tank, but not always.

Patterson tanks have a nice funnel system that fills bottom up without splashing on the film. The empty lid volumn allows really good inversion agitation and thus they are nearly fool proof. But have heard of people who do not use enough developer to cover the film. That leaves a low density streak along one edge. Nothing is perfect.

You can do any of these and get perfect results or invent your own as long as you follow the principles listed. Fast and even immersion. Vigorous and random agitation.

Photo paper is exactly the same.

 

[Maris]

Photographic image structure is surprisingly insensitive to agitation, or no agitation, during development. However the eye is acutely sensitive to even slight image artifacts and the influence of agitation can be demonstrated if one sets up an artificial condition, say laminar developer flow over a film surface.

Agitation will have no image structure effect if it is random or quasi-random. The key to a random flow pattern is turbulence. All successful agitation patterns, twirling, rotary, sloshing, inversion, in practice devolve into micro-turbulence down where the developer hits the film.

I take the agitation variable out of the development equation by doing constant random agitation for tray processing of sheet film.