I need help with Tmax Developer and Jobo 2520 tank.

Hi to all. This is my first post in this Forum.

I have a CPP2 with lift and want to develop Tmax film with Tmax Developer at dilution 1:7. Doing this way I have to use

81,25 ml of Developer ( I think this is the Minimum required ) and 568,75 ml of water, wich gives me 650 ml of final solution.

My question is : can I use this quantity of final solution , 650 ml, with Jobo 2520 tank or is too much to use in rotary

processing ?




I think Jobo 2520 and 2521 have the same capacity. If I folow the instructions of the picture, Rotation 270/560 ml, I can't

use 650 ml.

Or do I have to use dilution 1:4 instead ?

Thanks a lot

Luis

560ml/8 = 70ml
Tmax Developer = 70ml
Water = 480ml

Thanks for your answer Sirius. But I believe that 80 ml is the minimum of Tmax developer required. May be I am wrong.

Luis

galupi20 said:

Thanks for your answer Sirius. But I believe that 80 ml is the minimum of Tmax developer required. May be I am wrong.

Luis

Click to expand...

If your statement on Kodak recommended min quantity is correct then you are right inasmuch as this is 10ml less than the minimum quantity but I'd be surprised if 10ml is the difference between success and disaster. Two options: the bold one is to try it at 70ml and see if you can detect a difference. The conservative one: maintain 80ml and accept that you will have a ratio of 1+6 so certainty is guaranteed but you will never know if 60ml produces an acceptable result
There is a third option which gets closer to "squaring the circle" The tank might hold more than 560ml. Measure the max quantity to the brim and use that. I doubt if the quantity is as much as 640ml but you will get nearer to the magic 1+7. I wouldn't worry about the extra amount to the rim affecting agitation as the top of a Jobo tank has quite a large area for the liquid to go to when inverting.

Of course using a lower amount of liquid as per rotary development is out of the question unless you want to be very daring and see the effect of 270ml at 1+7. This means less than half the Kodak recommended amount. Kodak couldn't be that wrong about the minimum quantity required, could it?

On the other hand these minimum quantities do seem to be a "movable feast" in that a lot of people believe that the minimum quantity of stock Perceptol is 250ml but others here seem to have had success with as little as 150ml. I myself have has success( at least by my standards) of 60ml of Perceptol. For the sake of honesty and accuracy I need to add here that Ilford's recommended minimum of 250ml is based on an interpretation of what Ilford instructions say rather than an actual instruction in so many words. I wrote to Ilford and it said that 70ml was the minimum based on a tank holding 280ml.

Why the last para you may ask when you question is about Tmax developer. Simply that what Kodak says is the minimum( I take it that there is an actual K instruction to the effect that 80ml is the minimum ) and what still works may be two different things.

pentaxuser

Dilution should be 1:4, so multiply your tank volume by 0.2 to see how much developer the tank will hold.

galupi20 said:

Hi to all. This is my first post in this Forum.

I have a CPP2 with lift and want to develop Tmax film with Tmax Developer at dilution 1:7. Doing this way I have to use

81,25 ml of Developer ( I think this is the Minimum required ) and 568,75 ml of water, wich gives me 650 ml of final solution.

My question is : can I use this quantity of final solution , 650 ml, with Jobo 2520 tank or is too much to use in rotary

processing ?


I think Jobo 2520 and 2521 have the same capacity. If I folow the instructions of the picture, Rotation 270/560 ml, I can't

use 650 ml.

Or do I have to use dilution 1:4 instead ?

Thanks a lot

Luis

Click to expand...

Not sure where you got the information regarding the minimum concentrate amount from. Kodak gives a capacity of 16 films that can be developed in one gallon (= roughly 4 films per one liter) of developer for the standard dilution 1+4 without extending development times. This translates to around 50ml of concentrate per roll. Remember this is already a very generous number, as more films could be processed if we extended development times on subsequent runs. But this is not relevant for us, as you want to use the developer one shot, correct?Now, using this assumed minimum amount of 50ml of concentrate in dilution 1+7 will give you 400ml of solution per roll, which is perfectly okay for your tank, me thinks (unless you want to develop two films together)?

At 1:4

Hi mnemosyne. I got the information here :



1 gallon = 3.785.41 cc / 48 = 78,85 cc of developer per roll of 120.

I am confuse now. What am I doing wrong ?

galupi20 said:

Hi mnemosyne. I got the information here :

1 gallon = 3.785.41 cc / 48 = 78,85 cc of developer per roll of 120.

I am confuse now. What am I doing wrong ?

Click to expand...

I'll let those wiser than I give you their interpretation of what this means in terms of minimum quantity of stock per film but I have a feeling that prophetically this is covered in my point in my earlier post about Perceptol where some users have interpreted the minimum stock quantity from how many films Ilford says that 1 litre of Perceptol is needed for 4 films i.e. 4 films =1 litre for one film needs 250ml. I do not think that you can necessarily conclude this. Yes in a 250ml tank using Perceptol or any developer for that matter it needs 250ml of stock to cover the film but not necessarily 250ml of stock as the minimum quantity for successful development. Ilford gives times for Perceptol 1+3 for 135 film which can be developed in a 250ml tank so on the basis of 250ml stock being the minimum required then you'd need a tank holding 1L if you wanted to develop a film at 1+3. I cannot believe this to be the case.

I hope this makes sense to you. In my opinion you need to find a sentence issued by Kodak which states the minimum quantity of stock needed for a 135 or 120 film. Both film types have roughly the same surface area

pentaxuser

Let me answer this differently, it is really a matter of when chemical leaks out of the tank. If you are using the magnet on the tank instead of the lift you can pour all the chemical in, cap the tank and run it, I do that with my CPE2 all the time. If you are using the lift place the empty tank on the lift, start the motor and pour in 650ml of water. If it doesn't leak you are good to go. On a more practical note, you would probably not see a difference running it at 70ml per roll vs 80ml, but I would test it to confirm myself.

galupi20 said:

Hi mnemosyne. I got the information here :

1 gallon = 3.785.41 cc / 48 = 78,85 cc of developer per roll of 120.

I am confuse now. What am I doing wrong ?

Click to expand...

I am 100% sure that "one gallon" refers to the amount of working solution at the standard dilution of 1+4 (Kodak speak "1:4"), not the amount of concentrate. One gallon is exactly the amount of working solution that you can prepare from one bottle of concentrate (757ml, as sold in the US). The bottle size sold in Europe is different (one liter), so this relationship might not be as obvious depending on where you live.

Thanks a lot mnenosyne. You made me see it clear.