Roll Film AGITATION - Thornton's Two Bath

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Shawn Dougherty

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Thanks Gerald!

...development is essentially diffusion controlled. Therefore the user only needs to provide fresh developer to the surface of the film. One or two inversions is sufficient. Any additional agitation will cause problems.

Can you elaborate at all on what effect additional agitation would have, and what kind of problems might occur?

Thanks again for your time and insights with this.

-----------------------

Just to be clear, I can understand why a minimum amount of agitation in Bath B would be preferable but I am still unclear about any negatives additional agitation would have in Bath A (being basically a standard developer).
 
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ed1k

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Intense agitation in bath B will wash out solution A which is not what you want. I dare to suggest to stick to agitation technique you use and only vary time in bath A. And yes, temperature does affect contrast a lot, so I do adjust my time in bath A according to temperature. Better practice would be to stick to constant temperature as well. Time in bath B is not critical; technically you should give enough time for shadows to be developed and in some time developer will be washed out of emulsion. I usually leave my film for 10 minutes in bath B. However, I should mention that I always use fresh bath B (in my case it is cheap solution of borax 10 g/l). Contaminated with solution A bath B will produce different results and you can, in fact, overdevelop.
 
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Shawn Dougherty

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ed1k and Michael,
Yes, as I said, I can understand the reasons to minimize agitation in Bath B.

But, as you both say, Bath A is seeming like the place (in Thornton's Two Bath NOT Diafine) where one could really use agitation and time to control the highlights. My limited testing has certainly suggested this.
 

Gerald C Koch

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Too vigorous agitation can result in loss of film speed and shadow detail. For developers like Thornton's excessive agitation can result in surge marks. When baths are reused they become more prone to foaming. The bubbles formed can cause uneven development. Agitation should always be gentle.
 
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Shawn Dougherty

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Gerald,
I think I've got you. You are saying I should be careful of the intensity of agitation in Bath A (Thornton's Two Bath) not that agitation shouldn't be used as a tool, again, in Bath A.
Shawn
 

grahamp

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As an aside, it does work in continuous agitation systems, with the provision that you will possibly speed the dilution of Bath A into Bath B and lose some edge/compensation effect. But that is down to the diffusion rates in the emulsion. I have used a Jobo with 5+5 min at 21C with Delta 100 and 400 at one stop below box speed. I think the biggest issue with the Thornton developer is that it may be too flexible!
 
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Shawn Dougherty

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As an aside, it does work in continuous agitation systems, with the provision that you will possibly speed the dilution of Bath A into Bath B and lose some edge/compensation effect. But that is down to the diffusion rates in the emulsion. I have used a Jobo with 5+5 min at 21C with Delta 100 and 400 at one stop below box speed. I think the biggest issue with the Thornton developer is that it may be too flexible!

I've run across a number of threads where others state they are using Thornton's (or other two bath developers) in a Jobo or BTZS style tubes. I would love the see some curves comparing different agitation methods, including continuous.
 

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ed1k and Michael,
Yes, as I said, I can understand the reasons to minimize agitation in Bath B.

But, as you both say, Bath A is seeming like the place (in Thornton's Two Bath NOT Diafine) where one could really use agitation and time to control the highlights. My limited testing has certainly suggested this.

Hi Shawn,

not really sure what you are getting at here. Thornton's two-bath controls the highlights (i.e. they are never over-blown).

Varying agitation in both Bath A and Bath B may have some effect on mid-tones but the highlights remain controlled.

The image that is currently on my Homepage had a brightness range of more than 10 stops. The bottom right-hand side was metered and placed on Zone III and the film was developed normally in Barry Thornton's Two-Bath developer. The image prints fairly straight with good shadow detail and a trace of tone in the white walls in sunlight. The only dodging required was to slightly lighten the mid-grey area within the wall in shadow at the bottom right of the image.

I would suggest that you pick an agitation regime that you like (despite other posts, I never have any problems with one inversion every 30 seconds) and stick to that and concentrate on finding which development time suits your work.

Bests,

David
www.dsallen.de
 
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Shawn Dougherty

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It would then follow I'd use development time in bath A as a primary control of contrast, rather than varying agitation frequency.

That's my two cents at least. To me, with a general purpose, non-compensating developer, once you have an agitation scheme that produces consistent, even development, I wouldn't mess with it in an attempt to control contrast. Development time is always the easiest, least risky variable to change in any process.

Thanks for that, Michael. I have found changing the time by one minute makes a noticeable difference and my results have been perfectly even thus far. So, I shall steer future testing in the direction of adjustments in time.
 
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Shawn Dougherty

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Hi Shawn,

not really sure what you are getting at here. Thornton's two-bath controls the highlights (i.e. they are never over-blown).

Varying agitation in both Bath A and Bath B may have some effect on mid-tones but the highlights remain controlled.

www.dsallen.de

David,
Bath A is basically just a normal D23 type developer. Normal time and temperature changes affect the highlights like any other developer. The short amount of time in A is the primary control over the highlights. In Bath B exhaustion causes the highlights to pretty much stay where they are while the shadows continue to fill in. It's more of an after bath developer. It is not a true Two Bath Developer.


I would suggest that you pick an agitation regime that you like (despite other posts, I never have any problems with one inversion every 30 seconds) and stick to that and concentrate on finding which development time suits your work.

Bests,

David
www.dsallen.de

I agree, David. Thank you for all the contributions to this thread!
 

akitak9821

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Well in my observation it doesn't really matter what reel you're using as long as you're agitating at least 30 seconds in the first minute and 10 seconds out of every other minute.

My results consist of no film spots.. sooo take that any way you want :D
 

subsole

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Barry Thornton quote:

"The film is ’developed’ in Bath A with agitation every half or full minute -it’s not critical. Actually little development takes place. Mostly the film is becoming saturated with the developing solution. However, some development does take place and agitation is important to prevent streaking. The solution is then poured off and saved. Drain the tank well but don’t rinse or use a stop bath. Then pour in Bath B, and after a quick rap of the tank on a hard surface to dislodge any airbells, let the tank stand still with no agitation for three minutes or so when all development has ceased. Note, though, that while no agitation is ideal, and usually works well for unsprocketed roll film (120/220), there can be streamers from 35mm sprocket holes. This seems to vary with different kinds of tanks, different films, and the local water characteristics. Do your own experiments to determine the minimum agitation you can achieve without streaking before committing a crucial film to the process. Perhaps try one minute intervals to start with."

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I'm using Kindermann stainless steel tanks with 120 and 35mm film.
I don't agitate Bath B,never had any kind of streaking.

Cheers
Wolfgang
 
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Shawn Dougherty

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Thank you, Wolfgang.

As I said, I have all of Thornton's material and am not having any problems with streaking. Just running test and looking for others' experiences using agitation and time to alter negative contrast.

I've had excellent results with this developer thus far, everything I've developed has been well within the range of printable, which is quite impressive to me in the first place. Just trying to get things really dialed in at this point.
 

baachitraka

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May be it sounds silly. Just wondering, how much of Bath A and Bath B is used for one roll of 120 film?

Firstly, I do not use metal tanks - so this should be taken into consideration - but have exclusively used Barry Thornton's two-bath developer with 120 Delta 400 film for many many years.

The processing sequence that works for me (using Paterson plastic tanks) is as follows:

00:00 pre-soak with constant agitation
01:45 drain pre-soak out of the tank
02:00 Pour Bath A in and invert 4 times in the first 30 seconds followed by a sharp tap on the bottom of the tank to dislodge any possible air bubbles. Then one gentle inversion every 30 seconds always followed by a sharp tap on the bottom of the tank to dislodge any possible air bubbles.
06:45 Pour Bath A out of tank into a jug.
07:00 Pour Bath B in and invert 4 times in the first 30 seconds followed by a sharp tap on the bottom of the tank to dislodge any possible air bubbles. Then one gentle inversion every 30 seconds always followed by a sharp tap on the bottom of the tank to dislodge any possible air bubbles.
11:45 Pour Bath B out of tank into a jug.
12:00 Pour in water stop bath and agitate constantly
12:45 Pour water stop bath out into the drain.
13:00 Pour in fix and agitate constantly
15:00 Remove films from tank and place into a large jug of water and leave until all of the pink dye is removed from the film then return the film to the fix for a further 2 minutes.
Finally, wash using the Ilford method.

A note on mixing the chemicals and use
  • I mix up 1 litre of Bath A (my tank is the 1 litre version that can accommodate up to 4 films) and store in a 1 litre dark brown glass bottle. This one litre is sufficient for 24 films (but note the following point about Bath B).
  • I mix up two litres of Bath B at the normal 12g of Sodium Metaborate (which are stored in two 1 litre dark brown glass bottles) and use each bottle of Bath B for 12 films and then discard.
  • I mix up one litre of Bath B at the N+ dilution of 20g of Sodium Metaborate (which is stored in a 1 litre dark brown glass bottles) and use rarely when needed.

A note on the N-, N and N+ dilutions
  • 99% of all my photographs are developed with the N version of Bath B. I have never had any negative where I felt that it should have been developed using the N- version of Bath B.
  • The N+ version of Bath B is useful but not in the sense of a strict +1 stop expansion (which can be much better achieved by selenium toning the negative). If I photograph something that has dark shadows and bright highlights but also a significant part of the scene is relatively lacking in mid-tone separation then I use the N+ version of Bath B. This has a significant effect on expanding the mid-tones of a scene that was lacking such a mid-tone separation.

Having just quickly looked through the 100 odd images on my website, there are 6 photographs where I used the N+ Bath B and all of the rest were developed using the normal Bath B.

Best of luck finding your own best way of using Thornton's two-bath developer - it is a great, reliable and cheap developer.

Bests,

David
www.dsallen.de
 

mrred

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I just fill it up. It is not like it get's diluted or thrown out.
 

Black Dog

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Likewise-it's a very cheap and reliable developer IME.
 

baachitraka

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I just placed an order for the chemicals. Hope I can spend some time during holidays.
 

David Allen

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The amount of developer you use is simply determined by how much developer is required to cover the film in the tank or tray that you are using.

For example, I use Paterson plastic developing tanks. These require 300ml to cover one reel of 35mm film, 600ml to cover two reels of 35mm film, 900ml to cover three reels of 35mm film, 500ml to cover one reel of medium format film and 1000ml to cover two reels of medium format film. The reason I have written 'reels' is that, with medium format film, you can load two medium format films into each reel.

Apart from having enough developer to cover the film, the only other consideration is exhaustion of Bath B (1L will easily be sufficient for 16 films).

What I always do is process 4 rolls of medium format film loaded in to two reels in a 1L Paterson tank using 1L of Bath A followed by 1L of Bath B.

Bests,

David.
www.dsallen.de
 

baachitraka

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Thank you very much. Hope things will go find with RPX 400.
 

baachitraka

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I am very happy with RPX 400 + BTTB. Prints beautifully on Adox Vario Classic. I gave 4:45mins + pouring time. Grain is different compare to Rodinal but I like the smoother tones esp., negatives from Rolleicord.

Prints were made with Grade 2 filter.
 
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