Rodinal...Am I nuts?
Guys, it has been years since I used Rodinal. Mike W. Was very kind to send me a couple of big bottles so I did some testing with Ultrafine (rumored to be fp4) and I got some weird results. So my questions it this, does Rodinal become more active as it gets a little bit more oxidized? I made 500 ml of 1:25 developer and did testing developing times at 14, 11, 7, 3 minutes...well, the 14 and 11 minute are almost identical, with the 7 and 3 not far behind....what gives?
Did you mix 25 parts Rodinal to 1 part water AGAIN? So that's why you wanted the big bottles.
I have used Rodinal quite a lot (and I have way more than just 2 big bottles at home<g>). I can say that I have never seen it change activity as it gets older. I am using stuff that must be 5+ years old and it hasn't changed that I know of.
You're in a good position to verify this, though. One bottle I sent you was old and the other was bought new at the store just a few days before I shipped it. So, why don't you try a little from each bottle and let us know, eh? I know the store and they turn over inventory fast so it didn't sit there for more than a month at the most. Do you see much difference in the stock color - I'd expect the older one to be quite a bit darker than the newer one.
I would expect a noticible difference even between the 14 and 11 minute negatives. If you checkout my gallery, you'll see the boulder in the stream. That is EFKE 100 in 1:50 Rodinal for 13 minutes. I 'placed' the shadow in the boulder at a little above Zone III and the hot spots on the rock fell like on Zone X. I had not done dev. time tests (shame on me) so I just took published numbers for this combo. It seemed to work out ok - but the negative is very contrasty. It is giving AZO Gr 2 a tough time so far.
But I don't consider these densities abnormal. I know that I was using old Rodinal and if I cut the time back to even 11 minutes, the densities would certainly have dropped.
So, I can't account for what you're seeing. If it's due to the age of the developer, that would have to be one heck of a lot of more activity to account for what you're seeing.
Oh, in case you're wondering, I did NOT mix in any chemical into the Rodinal that I shipped - that's a dirty trick that even I would not do!
Take care and keep me posted. I can always send more......Hey this isn't just a ploy to get 'fresh' Rodinal out of me is it?
The difference between 11 and 14 minutes may be less than 10% in contrast index. It is a logarithmic function, of the same shape as the voltage on a capacitor being charged through a resistor from 0 to a constant supply potential: a rapid initial rise with a gradual decrease in charge rate.
Well yeah, but the diference between 14 and 7 is much greater, yet I got the same densities....same with the one at 3 min....the 3 min was only a bit lower...Essentially what my data is telling me is that this developer is only good for "normal" developement without being able to do expansion or contraction. Obviously this does not make sense....
Originally Posted by gainer
Mike, I meant once mixed with water, I did not mean to imply that the concentrate was bad. What I did was develop one step wedge, go out have a cig, check APUG, etc. Come back and do the other step wedge, overall the 1+25 solution sat about 1 hour while I was doing all the step wedges. All 4 negatives resulted in about the same densities...weird!
I have to do 1+25 for pt/pd, if I could get away with 1+50 I would but dont want to spend 30 minutes developing a sheet..
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That is very weird. I have always used the working solution immediately after mixing it. I have never let it stand for an hour like that. So, I can't really say for sure. But I can't imagine that would have any effect. Afterall, print developer stays in trays for longer than that and development times don't have to drastically change. Rodinal can be used for developing prints (so I hear) - I wonder what happens to it after it's been in the tray for a few hours?
Did you re-do the test and mix the working solution fresh each time? Also, if you only mixed 500ml and you developed a step wedge(s), are you sure you had the correct ratio of developer to sq. in. of film? Perhaps there was too little Rodinal in the working solution so that no matter what time was used, densities would come out about the same?
I know there is a minimum amount of concentrate required for a given sq. inches of film, but I don't know it off the top of my head.
Also, the poop sheet with my Rodinal says:
"Once diluted for use, Rodinal will only keep for a short time. Therefore, it is recommended that it is only mixed immediately prior to use. The working solution is discarded after one development cycle."
Did you re-use the working solution? If so, you can't do that with Rodinal. Also, apparently sitting around for an hour would violoate the rule to use immediately.
So, I'd say use it like everyone else. Mix it right before use (like 1 minute before use or less) and then discard it. That should give you consistent results.
Thanks Mike, I never reuse developer, to me that is just asking for trouble. So I used it one shot.
The BTZS tube cap holds about 80 ml, which should be enough for 1 4x5 sheet, which is the size I use for testing. If the problem was exhaustion I should see a difference between the 7 min and the 14 minute, yet, they are the same....
The only thing I can think of is the developer getting some extra humpf as it sits, so I will do as you say and mix immediately before use...we will see what happens.
I'm another who uses the working solution immediately after mixing it, so have not experienced the effects your finding. I wouldn't have expected any difference if used within and few hours so look forward to hearing the results of your tests on this one.
What I do find though is that once the concentrate has been openned and it's going through the brown colour changes it seems to improve.
Jorge, as you know I also use Rodinal, 1 shot and 1:100 stand or semi stand. I will send you the negative we have been discussing and let you get an impression from it if you want. Send me a PM and I will try to post it this week. Just for additional info, when doing roll film, I have made up 1L of developer (dil. 1+100) and used only part of it for one roll, then after about an 45-60 min started the next roll, have not noticed any difference, but that does not mean much - doubt I am as aware of my negs as you are.
The curve I described has a time constant. In electronics, it is RC or 1/RC. A developer has a similar constant. The maximum contrast index used to be called "Gamma infinity" and was a theoretical asymptote of the curve of contrast index vs time of development. The maximum contrast of HP5+ in Rodinal is about 0.65, which is approached quite rapidly in the 1+25 dilution, and never reached in the 1+50 dilution.