Calbe R09 Dilution compared to Rodinal

[b._poetz]

I have read conflicting information. Some say that Calbe R09 is MORE concentrated than

Rodinal, suggesting, for example, that 1:40 (R09) is the same---timewise---as Rodinal 1:50 or

that R09 1:75 is about the same as Rodinal 1:100. What's the scoop on diluting this soup?

How does one accurately convert from Rodinal developing times to R09 times? By the way,

has anyone actually observed any real differences between these two developers or is it more

legend than fact?

[ronald_moravec1]

R09 is more concentrated. I never worked out an exact ratio, but the 1:40 and 1:25 seem about equal.

 

They work the same as far as I can tell. Don`t panic when you open the bottle and find it looks like black ink. That is how it is supposed to be. After dilution, they are the same color.

[john_cook1]

I'll second Ronald's reply. Directions are accurate and the results virtually identical.

 

In addition, you might think about availability. B&H won't ship Rodinal - you have to drive to NYC and buy it in the store.

 

Also, Agfa has a reputation for suddenly pulling things off the market without warning. They have stabbed me in the back more than a few times since the 1960's.

 

J&C, my source for Calbe R09, will quickly ship the stuff to me. And they seem to be much more user friendly. Don't appear to think they are doing me a huge favor by selling me something and taking my money, like some German manufacturers I could name.

[b._poetz]

"...I never worked out an exact ratio, but the 1:40 and 1:25 seem about equal. "

 

Okay... but is there a ratio I can you to accurately and consistantly convert other dilutions? If I find

the perfect time for a Rodinal 1:100 dilution should I use 1:75 for the R09 and keep the same

time? I'm just quoting a number I've heard before, but without any idea of how one arrives at

1:75 for the 1:100 Rod. There must be some formula to convert. How do you do it?

[b._poetz]

One more thing... have either of you noticed a difference between the two developers? Do

you prefer the Calbe R09 or ....?

[ronald_moravec1]

They seem to differ by a factor of 1.6. 25=40 50=80 100=160.

 

therefor the ratios are 1:40, 1:80, and 1:160 for starters.

 

Whatever time you use for 1:50, now dilute 1:80 and try the same time. If you like rodinal at 1:100, use 1:160 Ro9 and try the same time.

 

I never did actually try this, but I liked Rodinal at 1:50, so I did my Efke 25 at 75:1 and was happy with the result.

[b._poetz]

If the concentration is really different, why then, does the Massive Developing Chart suggest

identical times for 1:100 dilutions of R09 and Rodinal (18 min.) for Efke 25 ???

[hil3]

I've used both. Haven't been able to find a mathematical correlation between the two and have tried. For instance, with TX at EI 200 and 20 deg, my time for R09 1:40 is 8m 30s; with Rodinal 1:50 it's 12m 00s; with Rodinal 1:25 it's 5m 30s. I haven't got results I liked at greater dilutions with either.

 

I lately prefer TX at EI400 with R09 1:40 20deg 11m. I use a plastic JOBO 2-reel tank, pre-soak for 1 minute in distilled, agitate for the first 30 sec and for 5 sec every minute thereafter. I've standardized on this because 11 minutes seem reasonable - less time too hectic, more time too boring and EI400 works almost always for me. I try to err on the side of over-exposure, but TX is very forgiving, right?

 

Can't say I see a difference between Calbe and Rodinal. I like the look of the grain and I like how my negs scan, PS and print with this routine. I get very similar results with HC-110 dil H, but prefer R09.

 

I can say that with R09 at 1:40, I don't get grain clumping that I see with Rodinal at dilutions greater than 1:50.

[dean_williams]

B. Poetz , apr 18, 2005; 08:06 p.m. wrote:

"If the concentration is really different, why then, does the Massive Developing Chart suggest identical times for 1:100 dilutions of R09 and Rodinal (18 min.) for Efke 25 ???"

 

There's no way to know for sure "why", but except for the manufactures times listed on the Massive, most of the rest are just times that people wrote in to them, as suggestions. The Massive is a great reference, but it isn't absolute. Anyone who has actually used R09 and Rodinal will know that they are not the same. Try using both at 1+25 for the same time, with the same emulsion shot at the same EI and the difference will be obvious. The R09 is more concentrated.

[b._poetz]

Achtung! Damen und Herren:

 

Regarding the seemingly factual statement that R09 is more concentrated than Rodinal,

everything I have found published, including the ORWO film processing chart

http://www.digitaltruth.com/chart/old/orwo_old.html which compares R. and R09 suggest

otherwise.

 

Now, I am the first person to say that empirical testing is the ONLY real way to discover truth.

Even well meaning advice can be tremendously misleading when one considers variables such

as enlarger variations, paper, film, agitation and so on. Not to mention that we all find different

ideals in contrast. This last factor -- the subjective nature of judging ideal negatives can't be

underestimated. Still, sharing experience and knowledge is often helpful and interesting.

 

Also, in ORWO's own "Developer R09 - Directions for use" the suggested time for NP15 (IS0

25) is "approx. 9 min." @ 20 deg. C. in a 1:40 dilution. Now... here's where it gets interesting:

ORWO suggests a Multiplying Factor of 1.5 for 1:60, 2 for 1:80, 3 for 1:100, 4 for 150 and 6 for

1:200.

 

Based on their suggested 9 minutes at 1:40, using a 1:150 dilution would require 36 minutes!

Obviously, I plan to test this -- arghhh! -- in the darkroom, but I thought this was intersting

information considering the 20 minutes time that seems to accepted by most here in this thread.

Remember, using Ronald Moravec's theory of a 1.6 factor difference betoween R. and R09,

the 1:150 dilution would be close to the 1:100 Rodinal dilution.

 

So, any thoughts on this... ?

[hil3]

I'm interested in continuing this discussion, mostly because I kicked the idea around a couple of years ago. So is the idea to try and find a correlation between Rodinal and Calbe R09? And the main assumption is that R 1:25 equals R09 1:40? So the time for R x 1.6 = time for R09.

 

That assumtion holds for me. With TX@400, my times for R 1:25 and R09 1:40 are 5m30s and 8m30s respectively. That's a 1:1.55 ratio - close enough to 1:1.6. So with TX and my technique, R & R09 are identical, almost, at 1:40. From this (only) one data point, I could assume that I should be able to look up dilutions and times for TX/Rodinal in the Massive Development Chart and dilute R09 the same way and get almost identical results, no?

 

If this is true, then, my times for R 1:50 x 1.6 should be almost the same as for R09 1:80. This is where it falls apart. My time for R/50 is 12m20s; for R09/80 it is 17m. The ratio is now 1:1.38. This seems to indicate that as you dilute the solutions, R09 is more active than Rodinal.

 

Comments, more data?

[b._poetz]

Hil... EXACTLY my point! The correlation of 1.6 multiplying factor appears to work but falls

apart in other instances.

 

Yes, I agree that the 1:40/1:80 R09 = 1:25/1:50 R. seems to be the accepted correlation

based on popular opinion. But, this certainly is a far cry from anything approaching scientific.

 

What I find really irking is that Calbe's own formula for Dilution/Multiplying Factor doesn't jive at

all!

 

For example, the generally accepted (MDC, PhotImpex, J&C) time for Efke 100 in R09 1:40

is 13m. Now, if you use Calbe's Multiplying Factor or '3' for a 1:100 dilution, you get 39

minutes! More than TWICE the duration of the 19 minute time published. Yet, the 6 m. time for

ISO 25 when Factored by 3 for a 100 dilution gets you 18 min. -- precisely the time suggested

on these charts. It just doesn't make any sense. And these are Germans! How can there be

such a gap in logic?

 

This isn't just an academic discussion. We're talking about the practical use of a chemical

formulation. Access to hard facts should not be this difficult. Isn't there someone from CALBE

or FOMA or ANYWHERE who can provide realworld definitive data? After all, R and R09

have been around for many years.

 

?