Replenishing D96 for 2 liter LOMO tank for 16 mm cine

Justas · Jan 28, 2020

Hello everyone,

I have a chemistry replenishing question.
Soon I will have to develop 4km of 16 mm film by hand using the LOMO 100 ft. 16 mm tank.
The tank uses 2l of chemical solution to make the development.
I will use Kodak D96 formula for the developer and I know that this developer is used in continuous machine process and it admits replenishment. The rate of replenishment is 625ml per 100ft of film, so basically it needs replenishment after every development. In the datasheets of Kodak the formulas for developer and replenisher is for 1 liter.
So the question is, if I use 2 liter stock solution to develop 100 ft. of film should I replenish it with 625ml of replenisher or double it to 1250ml since I am using double the amount of stock solution?
I mean if:
1l stock develops 100ft and replenishes with 625 ml
then
2l stock develops 100 ft and replenishes with 1250ml?

All this is to reduce waste and to get equal development in all the 4 kilometers of film.

Thanks in advance,
Justas

Kino · Jan 28, 2020

Develop 100 feet, discard 625ml of used developer and add 625ml replenisher to bring the total amount of developer to 2 Liters.

Repeat for each 100 feet; do not double-up.

The rate of replenishment is not dependent upon tank size; only film surface area developed.

Justas · Jan 28, 2020

Thanks!
That what I was thinking, and just asking to be sure. Of course, if i develop 100ft. and the replenisher formula is to compensate usage of chemicals of those 100ft. and not the total amount of the solution.

Kino · Jan 28, 2020

Justas said:
Thanks!
That what I was thinking, and just asking to be sure. Of course, if i develop 100ft. and the replenisher formula is to compensate usage of chemicals of those 100ft. and not the total amount of the solution.

Correct. Good luck!

Justas · Jan 28, 2020

And how much You think I can replenish the developer?

Kino · Jan 28, 2020

As long as you add the proper amount of replenishment, you can use it forever (with continuous use). If you have extended periods of time between development, start fresh.

Be sure to use the actual replenisher formula, not additional developer.

Justas · Jan 28, 2020

I would use these two formulas. D96 as stock and afterwards D96R as replenishment

Developer D96
Metol 1.5g
Na2SO3 75g
Hidroquinone 1.5g
Borax 4.5g
KBr 0.4g

Replenisher D96R
Metol 2g
Na2SO3 80g
Hidroquinone 2g
Borax 5g

Kino · Jan 28, 2020

Looks good.

I won't make too much of a point of it, but you will find that as the first reel developed in fresh developer is typically a bit more dense that the next when you use the replenishment system. The developer is "seasoned" as it is used and the complex byproducts of development are retained in the developer as it is being used, so the relative contrast/gamma will drop a bit.

Unless you are using control strips, you won't see this, but if you notice a considerable drop in contrast, you can boost the replenishment rate a bit to compensate.

Justas · Jan 28, 2020

Yes, it is true, the accumulation bromides in the developer does makes the difference. Also thinking that after certain amount of replenishment just mix a fresh stock solution and start from there again replenishing it...
Other thing that i was having doubts if that the film is poorly exposed and developed the replenishment also could over-replenish so next batch can be overdeveloped, does this make sense?
And no, I dont use test strips...;[

Kino · Jan 28, 2020

I would keep the replenishment uniform unless you are processing continuously and see a trend up or down.

Mr Bill · Jan 28, 2020

Kino said:
Develop 100 feet, discard 625ml of used developer and add 625ml replenisher to bring the total amount of developer to 2 Liters.

I'm sure that kino knows this, but a slight correction: since the film starts out dry but leaves the tank wet, this means that a small amount of developer is missing from the tank. If you follow Kino's directions exactly, you will gradually have less and less developer in your tank. So when you remove the 625 mL of used developer don't discard it right away. Add the replenisher, but then top the tank off (back to 2 liters) with the used developer.

What you are trying to do is to get all of the replenisher into the tank, but at the same time making sure that everything you discard is the used developer.

Kino · Jan 28, 2020

Mr Bill said:
I'm sure that kino knows this, but a slight correction: since the film starts out dry but leaves the tank wet, this means that a small amount of developer is missing from the tank. If you follow Kino's directions exactly, you will gradually have less and less developer in your tank. So when you remove the 625 mL of used developer don't discard it right away. Add the replenisher, but then top the tank off (back to 2 liters) with the used developer.

What you are trying to do is to get all of the replenisher into the tank, but at the same time making sure that everything you discard is the used developer.

Very true, Mr. Bill! Thanks for catching that!

We use continuous processing machines with 500 gallon tanks, so the replenisher displaces the existing developer and it overflows to waste. We don't have to worry about making up the volume!

Mr Bill · Jan 28, 2020

Kino said:
Very true, Mr. Bill! Thanks for catching that

Certainly! (Others also have done such work)

Kino · Jan 28, 2020

Mr Bill said:
Certainly! (Others also have done such work)

For sure, for sure...

Mr Bill · Jan 28, 2020

Justas said:
Soon I will have to develop 4km of 16 mm film by hand using the LOMO 100 ft. 16 mm tank.

That sounds like a lot of handwork. If I have this right, that's gonna be about 130 100-foot rolls through your tank.

Kino is right, that in principle you can run a replenished system "forever." But... the normal way to do this sort of thing is in a processing machine that has circulation pumps and filters. Without filtration you might end up with sludging and just a buildup of general crap in your system. Given that you will replace about 1/3 of your tank solution each run (~625 mL in a 2 liter tank) this may be enough to take care of things, especially if you can drain the excess from the bottom of the tank (this is where the sludge will tend to accumulate). I have no idea if this will become a problem; just pointing out the possibility.

Justas said:
Other thing that i was having doubts if that the film is poorly exposed and developed the replenishment also could over-replenish so next batch can be overdeveloped, does this make sense?

Yes, this can definitely happen. For example several rolls of low-key (mostly dark) work will barely stress the developer, whereas high-key needs more replenishment. If all of the work is the same "unusual type" the developer "activity" will shift to a different equilibrium over the course of several, perhaps as many as a half-dozen, cycles. This may or may not be a problem, depending on how far off things go, and how critical the results are. It might be worth making your own reference test strips, even just for visual evaluation.

Is this film already shot, or is it being exposed according to your process results?

phillykitty · Jul 1, 2023

Justas,
I was wondering how you came up with the 625ml/100' for the D96 replenisher? In the Kodak Data Sheet is says to calcuate the replenisher for 16mm negative at 40% of the rate listed for 35mm which is 1200/ml per 100'. Also wondering how your project turned out. Thanks.

Radost · Aug 3, 2023

phillykitty said:
Justas,
I was wondering how you came up with the 625ml/100' for the D96 replenisher? In the Kodak Data Sheet is says to calcuate the replenisher for 16mm negative at 40% of the rate listed for 35mm which is 1200/ml per 100'. Also wondering how your project turned out. Thanks.

Did you find out the replenishment amount?

Replenishing D96 for 2 liter LOMO tank for 16 mm cine

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