Single 35mm Roll in Two Rolls Paterson - Full Cap. Developer or Half Cap. Developer

[Mustafa Umut Sarac]

Our course instructor directed an attendee to half capacity - 300ml- use of developer in 2 rolls 600 ml capacity paterson for develop single roll. I did not like the idea to mix half full tank with lots of air inside. What do you say?

 

[koraks]

It's fine. The roll needs to be submerged, that's all, so ensure the reel is slid all the way to the end of the center column so the film sits at the bottom of the tank.

If you put that tank on a roller base so it sits horizontally and it rotates all the time, you could use even less. But you have to start taking into account the minimum amount of developer (concentrate) for a roll of film as stated by the manufacturer.

In short, your instructor is right.

 

[loccdor]

The Patersons have instructions on the bottom.

 

[Truzi]

You may also want to put an empty reel at the top. That way the reel with film won't slide up and down.

There is a risk the reel would stick on the middle of the center column and not be fully covered with the developer.

 

[Alan Townsend]

Our course instructor directed an attendee to half capacity - 300ml- use of developer in 2 rolls 600 ml capacity paterson for develop single roll. I did not like the idea to mix half full tank with lots of air inside. What do you say?

I use an old Beseler plastic tank that is similar to the Patterson, and always have gotten uneven developing along the top edge when using only one 35mm roll in a two roll tank using 360 ml developer with a spacer or without a spacer to keep the single reel from moving up on inversion. So I always waited until I had two rolls to develop. Bad practice.

Now, I use 480 ml developer for single reel, and do the figure 8 agitation method without any inversions, and that uneven upper edge of the film development has gone away. This is what I would suggest is to use more developer and avoid tank inversions. Those plastic reels have wedge shaped channels that likely cause turbulence from tank inversions. Using more developer is always good when using diluted developer to avoid developer exhaustion and getting more even results.

Frankly, using more like 360 ml developer with figure 8 agitation may be adequate for less diluted developers. Some experimenting with this may be best.

 

[MattKing]

FWIW, there are a lot of small differences between the now very old Beseler tanks and reels and the somewhat more modern Paterson Super Systme IV tanks and reels. I have no doubt there at least some differences in things like fluid flows.
I used to use one roll in a two roll tank reasonably frequently - with either an empty reel on top or a rubber band holding the single reel at the bottom - and got good results. It probably is a good idea to use an extra 50ml of liquid, just to be extra sure.

 

[Augustus Caesar]

Our course instructor directed an attendee to half capacity - 300ml- use of developer in 2 rolls 600 ml capacity paterson for develop single roll. I did not like the idea to mix half full tank with lots of air inside. What do you say?

Fill the tank all the way. Every time. Otherwise, the developer will slosh around and cause streaks.

 

[koraks]

Otherwise, the developer will slosh around and cause streaks.

This is nonsense.

 

[RalphLambrecht]

It's fine. The roll needs to be submerged, that's all, so ensure the reel is slid all the way to the end of the center column so the film sits at the bottom of the tank.

If you put that tank on a roller base so it sits horizontally and it rotates all the time, you could use even less. But you have to start taking into account the minimum amount of developer (concentrate) for a roll of film as stated by the manufacturer.

In short, your instructor is right.

Koraks brought it to the point. no need for a full tank of developer.

 

[snusmumriken]

Fill the tank all the way. Every time. Otherwise, the developer will slosh around and cause streaks.

This is nonsense.

I’m not so sure. In general, my experience agrees that 300ml chemical for a single reel in a double tank works perfectly, with no streaking.

But if you ever do get streaking, this would be one of the possible causes to consider. Funnily enough, it happened to me yesterday. I was developing Delta 100 in Thornton's 2-bath developer, with minimal agitation in bath 2. I normally use films with thicker emulsions (FP4+, HP5+, Double-X) in exactly the same routine, and suffer no streaking. The only explanation I can think of is that if the emulsion is thin, chemical flow is extra critical.

PS - these streaks are not surface marks, nor visible in the negative to the naked eye either.

 

[miha]

If sloshing developer causes streaks, rotary processors like JOBO would not exist. They rely on continuous movement of the chemistry over the film. What actually matters is proper agitation, not filling the tank completely..

 

[snusmumriken]

If sloshing developer causes streaks, rotary processors like JOBO would not exist. They rely on continuous movement of the chemistry over the film. What actually matters is proper agitation, not filling the tank completely..

Yes, yes. Please let us not get into another debate about 'proper' agitation styles. I've already said that I was doing minimal agitation.

 

[koraks]

I was developing Delta 100 in Thornton's 2-bath developer, with minimal agitation in bath 2.

The agitation thing is a much more plausible cause for the uneven development than the volume. Also, with a 2-bath developer and/or minimal agitation schemes, the wetting of the film can play a part. It may help to pre-wet the film (if you didn't already do this). The problem here is likely not the volume, but other factors at work.

If sloshing developer causes streaks, rotary processors like JOBO would not exist.

Precisely.

 

[snusmumriken]

@koraks, @miha , I don't disagree with you, except I'd point out that rotary processors turn the tank smoothly on its side - which is rather different from inversion agitation which separates the 300ml of chemical from a lone film into the roof space, and then lets it flood back up from the bottom of the tank. That takes a second or two, which may or may not be critical in some circumstances - I don't know.

But I will drop the issue now because I want @Mustafa Umut Sarac to understand that as a general rule 300ml is plenty of chemical for one film in a Paterson tank.

 

[miha]

There’s still quite a lot of internal strom going on inside a Jobo tank . The example shows an Expert tank, but the same basic principle applies to the reel tanks as well.

 

[koraks]

which is rather different from inversion agitation which separates the 300ml of chemical from a lone film into the roof space, and then lets it flood back up from the bottom of the tank. That takes a second or two

It's really fast though; you can calculate based on Newtonian physics how long it takes for the water/developer to drop back onto the film, approximately. It's definitely not a second or two; not even a fraction of it. Honestly, the situation of a 600ml tank half full of developer really is not different from a 1-reel Paterson tank. Low-agitation schemes are risky, but that's always true. And there can be issues in some configurations (film + developer +agitation) with uneven wetting, but again, that's not strictly a volume issue.

But I will drop the issue now because I want @Mustafa Umut Sarac to understand that as a general rule 300ml is plenty of chemical for one film in a Paterson tank.

Yeah, sorry for pushing the matter a bit; I think we're on the same page and agree that there's the larger scheme of things which is as you describe in the bold bit above, and there's a multitude of marginal conditions under which things start to shift, but IMO those can generally be easily avoided. Your example with the 2-bath developer is a good/representative one in that sense.

 

[Adam W]

You may also want to put an empty reel at the top. That way the reel with film won't slide up and down.

There is a risk the reel would stick on the middle of the center column and not be fully covered with the developer.

This is what I do. I have a couple of old reels that are hard to load and I keep them just for this purpose.