Delta 100 at ISO 64

I shot a roll of Delta 100 at ISO 64 and want to process it in Rodinal 1+50. I cannot find any times for that ISO. I have read that the highlights blow out pretty easily with Delta 100 and Rodinal--anyone using this combination or have suggestions for the processing time? I don't know if there is a formula to calculate this, or should I just interpolate 2/3 between ISO 50 and 100 times?

Pieter12 said:

I shot a roll of Delta 100 at ISO 64 and want to process it in Rodinal 1+50. I cannot find any times for that ISO. I have read that the highlights blow out pretty easily with Delta 100 and Rodinal--anyone using this combination or have suggestions for the processing time? I don't know if there is a formula to calculate this, or should I just interpolate 2/3 between ISO 50 and 100 times?

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Sorry Pieter12, I would help you with some Times of Delta 100 at ISO 25 in Ilford perceptol but ISO64
in Rodinal ? I remember stand developing at 1:200 in Rodinal but not with Delta films....

It may have a reason of the lack of information with your special case.
Perhaps you should decide on a clip test,?

with regards

Without having a clue what is on your roll of film, try 9 min. @ 20C. Constant agitation for first 30 sec, 5 sec every minute. I'm going by memory, shooting this film in sheet film and developing in Rodinal 1+50 back in the 90's. I also developed it in 1+100 dilution, but cannot remember the time... I think it was around 14 or 15 minutes...

Did you expose at ISO 64 by error or did you have a reason (subject matter or lighting)?

Totally intentional.

If it was my call, I'd do 10 minutes @ 1+50 if the subject matter was in contrasty light and 11 minutes if in flat lighting. Wouldn't get too carried away with my agitation.

Thanks. I interpolated from the Massive Development chart and did 11:30. Lighting was all over the place, from foggy beach to midday sun. Negs look a bit too contrasty but I haven't proofed or printed anything yet. I am more interested in the beach shots anyway.

See. You should have used my suggested time.

Pulling the development doesn't do anything except lower the overall contrast of the negative;
changing the exposure only alters how much detail will be recorded from the the shadows of the scene.

Did you really need to reduce contrast while increasing shadow detail?

Ilford published a chart showing Delta 100 at EI 50 and at EI 100, a depending upon the dilution of Rodinal used, the time was adjusted...(assumes 68 degrees)
Rodinal 1+25: EIm50, 7 min; EI 100 9 min.
Rodinal 1+50: EI 50, 10 min, EI 100 14 min.

I would simply use EI 50 times, as what you metered may well be NOT all that precise (to correct 1/3 EV) but I suppose you could assume 11 min (and metered perfection! )

Pieter12 said:

I shot a roll of Delta 100 at ISO 64 and want to process it in Rodinal 1+50. I cannot find any times for that ISO. I have read that the highlights blow out pretty easily with Delta 100 and Rodinal--anyone using this combination or have suggestions for the processing time? I don't know if there is a formula to calculate this, or should I just interpolate 2/3 between ISO 50 and 100 times?

Click to expand...

what does the great dev chart recommend?

Just use the time for the box speed. Your shadows will ride 2/3 EV higher on the logE-D curve. They will be happier. As for you, either you won't notice, or you'll be happier as well. And have more time to devote to walking out with your camera.

RalphLambrecht said:

what does the great dev chart recommend?

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The chart just has times for ISO 50, 100, 125 and 200 for Rodinal 1+50, no 64 or 80 for any dilutions,

Pieter12 said:

The chart just has times for ISO 50, 100, 125 and 200 for Rodinal 1+50, no 64 or 80 for any dilutions,

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Hi Pieter12.....
so what is to do now ?
In general : Such charts are no federal law, I remember often to look at such recomandation and wonder. Realy Ilford PanF with 7:30 ??? For example. Sometimes I did not care about and got fine negatives - sometimes I had better listen to a manufacturers recomandation......
But I can't remember a single case with development (in bw...) were negatives came such bad AS I remember and proved from normal procedure out of the 70th with comercial labs.

Think about and just try to make own experience. You don't ridc your live from that I sugest?

What have you shot ? Ok perhaps your live is in danger when your film isn't superb 1070% - I can't
know.

Just "middle" the times from 50 and 100ISO. Just compare from other charts the advance of development (from duration) in higher delution (if you need 1+100 Rodinal).
Ok your Film is not listed there : What hapened with other Films at 1:100 in comparison to 1 :50.
In short : calculation is sometimes more exiting - some others whant to have facts ?¿ before to come on own thoughts.

Bon Chance

with regards

PS : ISO 64 is 1/3 stop more speed if we calculate 100% correct. The middle would also be fine from my point.

Forgetting to state : If you got temperature compensation chatrs for Rodinal it isn't highest math
(use a calculator) to come with different developer temperature from ISO 50 to ISO64 (0,8 degree C for example) from different dilution it seams to be more complicate.
But if you will use the time given for ISO 50 (and you shot your Film at E.I. 64. and want to be 100% correct (in concern of a chart) you may use dilution and add. some water.
For example Rodinal 1 + 64 instead of. 1 + 50 ? It isn't such easy because you then have "higher maths"
Higher maths to Trendland I should state....because of logarithm function!

But from my first thought I came back at last : What about a clip test Pieter12?

with regards

Best hint I also remember at this time....if your Film is finished (with that time x and Rodinal y delution) Start your own chart. You may feel your Film is fine for you at last - but for the next run you may Chance something to feel better with your highlights.

It looks like an oldschool method but real Gold is also oldschool isn,t it ? (Inkas used it before.....)

Don't forget to "note" Times and Delution every time up to now. Because that will be your Darkroom "Gold" for the future. And the day will come when you may "waste" published recomandation from the net (often there are mistakes from transcription)

with regards