I wonder if I should move my Adox Rodinal to a glass bottle. So far I've kept it in its original plastic bottle.
All I can say is that I bought the original Agfa Rodinal in 2005. It had been reduced in price a little as the shop was trying to clear out older stock. It was and still is in its original white plastic bottle. I used it a couple of months ago and it worked fine
pentaxuser
Similarly with me. I’ve got a couple of bottles bought in the early noughties. The 500ml one I’m currently using was opened in the late noughties, is now very dark and still works perfectly ok.All I can say is that I bought the original Agfa Rodinal in 2005. It had been reduced in price a little as the shop was trying to clear out older stock. It was and still is in its original white plastic bottle. I used it a couple of months ago and it worked fine
pentaxuser
I really doubt that; I'd expect the opposite. Higher pH means in principle there's more opportunity for the developing agent to oxidize and be rendered inactive. In rodinal, a copious amount of sulfite is present to provent this from happening.I also want to add that Fomadon R09 has a pH of 11.8 whereas Adox Rodinal/Adonal has a pH of >13. I bet the higher pH/higher hydroxide content in Adox's version allows it to keep better.
I really doubt that; I'd expect the opposite. Higher pH means in principle there's more opportunity for the developing agent to oxidize and be rendered inactive. In rodinal, a copious amount of sulfite is present to provent this from happening.
The hydroxide content will need to be set such that the target pH of the working strength developer is met; this by necessity will have to be the same pH for the foma and the adox product; both are supposed to Rodinal variants/clones, after all, so logically the working strength solution will need to be equivalent. Both are based on potassium hydroxide so we can quite safely assume that the amount of hydroxide in both these products will be roughly the same.
The difference in pH is likely due to the effect of adjuvants (note e.g. the zinc powder) in the bottled mix; I personally wouldn't pay much attention to the pH of a rodinal concentrate since it can be qualified in any case as "godawful high". In the end, it doesn't really matter whether it's nearly 12 or over 13; either way it's as alkaline as things can realistically get.
Just do the math using different concentrations of NaOH with these pH numbers. You'll realize that there has to be more going on and that a difference in NaOH concentration cannot be the full story. Keep also the w/v percentage of NaOH listed in the SDS in mind.the only reasonable ingredient that can raise it's pH from 11.8 to 13 has to be more hydroxide.
I've used the R09 Rodinal and had the same experience--about 18 months then nothing.
Which one? There are many Rodinal clones in the market called R09.
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