Do rotary processors affect how the film looks in the end? (tonality, film speed / shadow detail, etc.)

[dcy]

It seems that you're taking one specific phrase from one previous post very literally despite having been explained that it's not how it works. It's really a matter of absorbing more information than just that single phrase.

If you take a typical film development tank and turn it over manually, the liquid flow patterns will be highly turbulent. There won't be unevenness due to laminar flow issues. It doesn't matter if the tank is also turned along a different axis; just tilting it 180 degrees will do the trick just fine. There's no way whatsoever that this will create laminar flow patterns across the film surface.

To highlight that point, here's the diagram from Kodak instructions --- I forget which product this is from; probably a Kodak-branded chemical made by PSI.

Here's a similar diagram from the C-41 kit:

Clearly, a simple inversion is perfectly sufficient. The fact that some of us are discussing more complex rotations doesn't mean that complexity is necessary.

 

[MattKing]

I feel like an idiot because I keep coming back to this and it looks like something that should be easy to understand but I'm not understanding. Let me write something that I think is *not* what you are saying, but the concrete example might help clarify my confusion:


(a) Hold the tank vertically. Left hand at the bottom, right hand on the lid.

(b) Grasp the bottom of the tank firmly with my left hand. Rotate the tank upside down, clockwise direction from my POV, allowing it to slide (rotate) across the palm of my right hand. The natural action of my wrist imparts both inversion and about 45 degrees of rotation.

(c) Left hand is now on top, right hand at the bottom. Loosen the grip of my left hand, and grips the lid (now at the bottom) firmly with my right hand. Rotate counter-clockwise to return the tank, and my arms, to their original vertical orientation. This time, the tank slides (rotates) across the palm of my left hand. The natural action of my wrist, combined with the hand switch, imparts an additional 45 degrees of rotation. So while the tank is right-side-up again, it has now rotated 90 degrees along its major axis.


I feel that at this point I've described steps (1) - (3) in your post. At step (4) I get lost. At the end of my step (c) my left hand is at the bottom, right hand on top, and I cannot impart a further counter clockwise rotation because my arms just don't bend that way. Perhaps I am supposed to switch hands? --- Hold the bottom of the tank with my right hand and the top with my left?

You hold the tank between your palms. Your fingers just steady it. All the motion comes from your arms and wrists.
And the solution inside tumbles through the reel(s) and film(s). All the rotation does is break up any flow patterns in the tumbling liquid.

 

[MattKing]

To highlight that point, here's the diagram from Kodak instructions --- I forget which product this is from; probably a Kodak-branded chemical made by PSI.

View attachment 407160

Here's a similar diagram from the C-41 kit:
View attachment 407161

Clearly, a simple inversion is perfectly sufficient. The fact that some of us are discussing more complex rotations doesn't mean that complexity is necessary.

Note that the illustrated tank is a small one, easily grasped in one hand.
I usually use a 1 litre Paterson tank, which is a bit harder to agitate with a single hand. Sometimes I'll use an even larger tank.
The two hand method works for a range of sizes, and allows you to be consistent in the amount of chaos you add to the process - and yes I notice the irony of that observation.

 

[MattKing]

For clarity, there are two things you are attempting to accomplish:
1) you want to be sure that the development and other steps of the process are not uneven; and
2) you want to be sure that the results of the development and other steps of the process are consistent from roll to roll.
I find that the two hand method is good for ensuring both, because it is fairly easy to apply repeatably.
Repeatability is the strong suit of rotary processors - that is why I use it for most of my film development workflow.

 

[mshchem]

 

[Bill Burk]

I feel like an idiot because I keep coming back to this and it looks like something that should be easy to understand but I'm not understanding. Let me write something that I think is *not* what you are saying, but the concrete example might help clarify my confusion:


(a) Hold the tank vertically. Left hand at the bottom, right hand on the lid.

(b) Grasp the bottom of the tank firmly with my left hand. Rotate the tank upside down, clockwise direction from my POV, allowing it to slide (rotate) across the palm of my right hand. The natural action of my wrist imparts both inversion and about 45 degrees of rotation.

(c) Left hand is now on top, right hand at the bottom. Loosen the grip of my left hand, and grips the lid (now at the bottom) firmly with my right hand. Rotate counter-clockwise to return the tank, and my arms, to their original vertical orientation. This time, the tank slides (rotates) across the palm of my left hand. The natural action of my wrist, combined with the hand switch, imparts an additional 45 degrees of rotation. So while the tank is right-side-up again, it has now rotated 90 degrees along its major axis.


I feel that at this point I've described steps (1) - (3) in your post. At step (4) I get lost. At the end of my step (c) my left hand is at the bottom, right hand on top, and I cannot impart a further counter clockwise rotation because my arms just don't bend that way. Perhaps I am supposed to switch hands? --- Hold the bottom of the tank with my right hand and the top with my left?

In his example you look like you’re driving, turning right, then left.

My technique is one hand, holding the tank with index finger securing the lid on.
I’ll do three full right and left actions (whish whoosh, whish whoosh, whish whoosh), on the fourth I rotate right, then come back to vertical and hit the butcher block hard. Whish, whomp whomp whomp. Then return to the bath.

 

[dcy]

Note that the illustrated tank is a small one, easily grasped in one hand.
I usually use a 1 litre Paterson tank, which is a bit harder to agitate with a single hand.

Yeah. I use a 2-reel Patterson tank that wouldn't be comfortable to agitate with one hand.

You hold the tank between your palms. Your fingers just steady it. All the motion comes from your arms and wrists.

In his example you look like you’re driving, turning right, then left.

So... in Matt's method the tank is not sliding across the palm. Right? I think I was confused by Matt saying that the method imparts both rotation and inversion. I took it to mean that the tank is spinning along its axis at the same time that it is being inverted, somewhat similar to the device in the video that @mshchem just shared.


Do I understand correctly that Matt's method is just doing 180 degree inversions? Similar to the Kodak diagram I posted, except with two hands? ... i.e. My hands could be glued to the tank, just like my hands could be glued to the steering wheel of my car.

My technique is one hand, holding the tank with index finger securing the lid on.
I’ll do three full right and left actions (whish whoosh, whish whoosh, whish whoosh), on the fourth I rotate right, then come back to vertical and hit the butcher block hard. Whish, whomp whomp whomp. Then return to the bath.

By "action" do you mean "rotate 180 degrees"?

 

[Vaughn]

Somewhere along the line I learned a toss-it-over-your-shoulder method for SS tanks. I use tanks that hold two120 SS reels. Holding the tank with both hands, a finger or two over the cap, I just sort of quickly toss it over a shoulder without letting go (so far) -- twice over each shoulder every 30 seconds. I suppose the idea is to shoot the developer nicely though the reels of film. I can hear the reels slide up and down in the tank. Then a thump on the heel of my hand to dislodge bubbles (saves the counter surfaces).

Works fine. Good upper body exercise, too.

I do find that with 120 film on SS reels in SS tanks, I do need more than the usually suggested agitation during fixing. YMMD

 

[MattKing]

Do I understand correctly that Matt's method is just doing 180 degree inversions? Similar to the Kodak diagram I posted, except with two hands? ... i.e. My hands could be glued to the tank, just like my hands could be glued to the steering wheel of my car.

Try it with an empty tank or something of similar shape and size. You will see that in addition to inverting the tank the movement of your arms and wrists will end up rotating the tank as well. Otherwise bones will break!

 

[Paul Howell]

I have small one SS reel tanks up to 8 SS tank and a 3 reel Patterson. I can invert the smaller SS tanks up to 4 reel and the 2 reel Patterson with one hand. I use deep tanks with film hangers for sheet film which takes 2 hands to raise the hangers up and out for agitation. I use a Unicolor film drum when using MCM 100 which has a very long development time and when developing more than 2 rolls of 35mm or 1 roll of 120.