Minimum amount of Rodinal

david_parmet1 · August 2, 2001

I know this question has been asked and answered before but I can't seem to find the answer.

What's the minimum amount of Rodinal necessary for roll film development? I'm diluting 1:75 and 1:100 for 120 film. My tank holds 500ml so that would leave me with either 7.5ml or 5ml of the juice. Is that enough? Should I use a larger tank?

thanks

david

pete_andrews · August 2, 2001

The Agfa recommendation is 18 films per 125ml of Rodinal concentrate,

which works out at just under 7ml per film. I presume they mean 36

exposure 35mm, which has the equivalent area to about one and a third

rolls of 120. So, just over 5ml per 120 film is within Agfa's spec.

I admit I've personally never used Rodinal with 120 film at those

high dilutions, though.

ed b. · August 2, 2001

I have used Rodinal at 1:100 and 1:75 in 500ml tanks for 120 film

with no apparent problems. I usually only use such high dilutions for

slow films.

john_stockdale · August 2, 2001

What happens if you have slightly insufficient developer? I suppose

development proceeds normally until exhaustion approaches, then what?

I recently tried to ascertain whether 250mL of normal PMK was really

adequate for a 36exp 35mm film, and I could not tell the difference

between it and using 500mL. I judged this by some zone_1 frames at a

range of speeds. Exactly the same, as far as a "proper proof" was

concerned. I have no access to a densitometer. I did not test for

heavily exposed frames. If those were the only ones affected, maybe

it would be useful rather than a problem to allow exhaustion.

pete_andrews · August 3, 2001

Hi John. "What happens if you have slightly insufficient

developer?" The maximum density is curtailed, and it's called

compensating development.

ted_kaufman · August 3, 2001

Insufficient developer quantity is not called compensation, it is

called exhaustion--thus, failure. More importantly, if developer is

used to exhaustion, there is no way to ensure consistent, repeatable

results.

As for using 250ml of PMK for one 35mm roll, Gordon Hutchings claims

in his book that this quantity is sufficient.

n_dhananjay3 · August 3, 2001

Actually, every compensating development technique I know relies on

controlled exhaustion as the mechanism. That is, you want the

developer to exhaust in the highlights but keep working in the

shadows. Its also a good idea to distinguish between using a

developer that is 'in a state of exhaustion' from using a

developer 'to exhaustion'. The former typically refers to using a

developer one-shot but the developer is compounded to be in a state

of exhaustion (a good example is POTA - it is in a state of

exhaustion from the moment it is compounded). The latter refers

typically to reusing a developer till it reaches exhaustion. The

latter is problematic for ensuring consistency because the

composition of the developer changes in addition to its getting

exhausted (repeated development adds bromide to the solution etc

which is likely to affect speed in addition to the maximum density

obtainable etc). OK, that's my pedantry fix for this morning. Cheers,

DJ.

dan_smith · August 3, 2001

This is what I received from the fine folks at Agfa when I asked this

a bit ago.

Subject: Response to Minimum amount of Rodinal needed per 8x10 film

unit?

Dear Dan,

in our technical data we mention that 500 ml concentrate of RODINAL

will last for 50 films (135-36). That means that you need 10 ml

concentrate to process 1 film. It does not matter what the dilution

is. Important is that you are using 10 ml concentrate. For example if

you are processing with a dilution of 1+50 than you need 10 ml

concentrate plus 500 ml water so that you will have in total 550 ml

solution to process your film. Why is it importatn to take 10 ml

because these 10 ml contain the amount of substances which will be

used to process your film correctly and with reproducible results. It

can be that you will get good results with less than 10 ml as

mentioned in one answer but to be sure we recommend 10 ml.

I hope this will answer your question.

If you have further questions please do not hesitate to contact me.

Kind regards

Wolfgang Holz

Product Manager

Marketing Chemicals

Agfa-Gevaert AG

john_stockdale · August 3, 2001

Ted: I know GH says 250mL is enough. I shouldn't have doubted him! I

was just responding to the suggestion in Anchell + Troop where they

suggested 500mL for developers in a category of developers at a

certain dilution rate.

Compensation: developer exhaustion (due to inadequate quantity) may

well be different to a dilute developer becoming exhausted in the

emulsion. I'm not sure what to expect.

Consistency + Repeatability: Good point. Strength of my favourite

developer (PMK) may well be a bit variable with age, chemical purity

etc.

mike_r1 · August 25, 2001

Im rather confused about this post :-

Dan posted it from Agfa,

"