Kentmere 400 pushed to 800 or 1600 with Rodinal

[loccdor]

Interesting. I think I've always used Rodinal immediately after mixing.

 

[koraks]

With Rodinal, it seems highly prone to aerial oxidation at working strength.

Okay, but if that's the issue at hand here, I think the example posted by @Milpool above says enough. Yes, rodinal oxidizes readily, but it'll work fine for 1 hour at least, even at 1+100. So it's not as extreme as you make this out to be. Other developers can be more problematic in this regard; esp. staining developers like 510 pyro.

 

[Lachlan Young]

Okay, but if that's the issue at hand here, I think the example posted by @Milpool above says enough. Yes, rodinal oxidizes readily, but it'll work fine for 1 hour at least, even at 1+100. So it's not as extreme as you make this out to be. Other developers can be more problematic in this regard; esp. staining developers like 510 pyro.

With some films, with enough solution volume - which does not equal all films. The test was also done to look into stand development - if you add enough agitation to resolve the major uneveness that @Milpool mentions, that will effectively aerate the developer too, unless you use nitrogen gas burst (I think some of the testing by others was done with regular agitation). A density/ time curve would demonstrate when diminishing returns rapidly set in, but would require much more extensive work.

I'd also add that the 30 min result is roughly equal to what Agfa (US) suggested would be the outcome of 20 mins with regular agitation, and that the average gradients and curve shapes tell a key story about something that can be achieved in much less time with Xtol and regular agitation (and the potential to land higher aim densities).

 

[koraks]

As to the agitation - sure, it would make a difference. The other points, I'm more skeptical about. There's not enough dissolved oxygen in any film to explain why rodinal at any sensible dilution would deplete after 30 minutes with one film but not another. The notion of curve shapes and gradients all nice and all, but not directly related to the question whether rodinal poops out after half an our.

I think @Milpool's test shows beyond any reasonable doubt that what you said earlier was exaggerated. There might (will) be diminishing returns, but that doesn't place them at firm zero after 30 minutes as you implied earlier.

 

[Raghu Kuvempunagar]

There might (will) be diminishing returns, but that doesn't place them at firm zero after 30 minutes as you implied earlier.

Just curious. Has Agfa (or now Adox) made any official statement on the expected life of Rodinal working solution after it has been mixed from the concentrate?

 

[koraks]

Not really, and I wouldn't expect them to because it's kind of a vague situation where activity is in a grey area and drops off rapidly. Here's what they say in the datasheet for Rodinal/Adonal (which actually is an Agfa datasheet they still use):

This leaves an open question what constitutes "a short time".

 

[loccdor]

510 pyro

I can say that I've been able to overdevelop a film with 510-pyro 1+300 stand development for one hour. That film was Delta 100. Frames became somewhat usable with DSLR digitization but were unusable out of an Epson with all adjustments off. I eventually stopped using 510-pyro at dilutions other than 1+100 because I found the times too unpredictable, unlike Rodinal where an hour seemed to do a decent job on just about everything. Maybe I needed to go to 1+500 to get the results I was looking for, but it definitely didn't strike me as a developer that tapered off.

 

[mzjo]

My walk around film in 35mm is Foma, less expensive Kodak or ILford and about the same as Kentmere, but even in 35mm the anti -halogen layer works better for me in the glare of the desert sun. I do not use Kentmere or its rebranded version only due Foma's 120 curl, I use Foma sheet film in MF and LF size. I find the tones of 200 to be odd, could be that Foma 200 is a mix of T grain and traditional grain. What is nice about 200 is that I can shoot at pretty close to box speed while I shoot 100 from 50 to 80 and 400 from 100 to 250 depending on the developer. Kentmere is also DX coded which is needed when I am using one of my point and shoots without DX override.

Rereading my day book the image I took in the 70s was developed in Rodinal 1:25 at 75 degrees for 30 mint, my note says time was a WAG, which means wild ass guess.

My regular 35mm film is also Fomapan 100, because bought in bulk it's affordable on a tiny pension! I like it (but not more than FP4 that I shot in the 80's and also bought in bulk). When I have a camera with a working meter it's box speed, when not it's a guess or a toy camera without adjustment. It just works for me! I have one p&s camera that tends to favour slow speeds and in which I use K400 (DX coded and a metal cassette). In box cameras I like Fomapan 200 because it's just so flexible. Pity about the black spots that I can't get rid of with my scalpel without wrecking the print! I do not like Fomapan 400 because of the plastic cassette (light leaks straight out of the box and the cassettes won't even fit in some of my cameras). The alternative for me is K400 or Agfa APX400 which are reasonably close to Fomapan prices through internet suppliers in EU. If I used more 400ISO I would probably go to Fomapan to bulk load but I only have one loader and I prefer slower speeds. Gone are my days of Pan F and Tri-X developed in Perceptol - that's poverty (I think!)

I have recently taken to stand developing with Rodinal (not for everything but there is a convenience in being able to load the tank and leave it work while I do something else). 60 minutes development. I use a spacer to raise the reel which means that while my dilution is 1:100 (ok 1:99 really) I am using 8ml of developer for a 35mm film instead of 6ml (1:50) that I would use developing with agitation. The spacer means that I need 800ml of liquid to cover the reel (I think when I measured the volume for 35mm film it was less but 127 is about 800ml so I keep it the same for both). After reading this thread I ought to try a test at 30 minutes and a parallel one at 60 minutes to see if I can see a difference but it would only be by eye and subjective, I am not equipped for measuring densities! I use Rodinal for some cameras like p&s where it seems to suit and D-76 for the more serious stuff. If I wanted to push the developing it would be with D-76 but it's not really my style, I prefer to avoid it and just use slower speeds.

 

[Raghu Kuvempunagar]

Not really, and I wouldn't expect them to because it's kind of a vague situation where activity is in a grey area and drops off rapidly. Here's what they say in the datasheet for Rodinal/Adonal (which actually is an Agfa datasheet they still use):
View attachment 418271
This leaves an open question what constitutes "a short time".

Good question for @ADOX Fotoimpex or Mirko to answer. Given that many users of Rodinal do stand or semi-stand development these days, a definitive answer would surely be helpful.

 

[Raghu Kuvempunagar]

I eventually stopped using 510-pyro at dilutions other than 1+100 because I found the times too unpredictable,

There is very little Phenidone in the developer at such dilutions and that could be making things unpredictable.

 

[koraks]

Without wanting to be facetious, what do you expect from this hypothetical answer - which I'm quite sure we will never receive? Given the nature of the developer, the manufacturer cannot be realistically expected to state on the record "it will last for x minutes/hours". It basically goes downhill from the moment of mixing, and the only honest answer how fast that goes is a firm and secure "well, it kind of depends..."

 

[Milpool]

Oxidation issue aside, I can imagine people getting different sensitometry results due to temperature drifts / gradients etc. Since I was trying to get as close as I reasonably could to "stand" for some sort of baseline ideal I tried to control for these variables the best I could. I doubt people generally do that though, because the technique is often assumed not to require control.

In any case, my findings were that it doesn't seem to do what people think it does from a "macro"-sensitometry perspective. Even if you can tolerate the poor uniformity, I'm not sure what is to be gained. If the motivation is pushing, this does nothing special - it just increases the gradient. If the motivation is to have some sort of automatic process for all films etc., this doesn't give you that. If the motivation is enhanced edge effects, while my results are silent on that front there are better/easier/less problematic ways to get edge effects.

With some films, with enough solution volume - which does not equal all films. The test was also done to look into stand development - if you add enough agitation to resolve the major uneveness that @Milpool mentions, that will effectively aerate the developer too, unless you use nitrogen gas burst (I think some of the testing by others was done with regular agitation). A density/ time curve would demonstrate when diminishing returns rapidly set in, but would require much more extensive work.

I'd also add that the 30 min result is roughly equal to what Agfa (US) suggested would be the outcome of 20 mins with regular agitation, and that the average gradients and curve shapes tell a key story about something that can be achieved in much less time with Xtol and regular agitation (and the potential to land higher aim densities).