Concerned about how old your Rodinal is?

[icebear]

Why anyone would take a chance on their negatives and use potentially old chemicals to try to develop them is just beyond me. It's not that the chemicals do cost an arm and leg. But oh well SD cards don't go old anyway.😉
Have fun in your darkroom adventures.😀

 

[ChrisPlatt]

I would never ever use marbles or buy compressed gas to squirt into my developer.
Too much trouble! I choose Rodinal (and HC110) for simplicity, ease of use and longevity.

I have no way to authenticate these reports, but they are there nonetheless.
I suppose I'll just have to wait 100 years to see which Rodinal clone is best... 🙄

Chris

 

[Freakscene]

I looked over the various formulas. At one point there was a change from sodium hydroxide to lithium hydroxide. The only reason I could think of to do this is the Lithium hydroxide would be more active than sodium hydroxide. Possibly it was cheaper at the time but would essentially do the same thing. They're both strong alkaline agents which raise the ph of the solution.

The alkali has no effect on Rodinal's keeping properties.

I described some of the chemistry associated with the para-aminophenol in Rodinal here: https://www.rangefinderforum.com/forums/showpost.php?p=1256895&postcount=22

Also sodium Sulfite was used. This often is used as a silver silver to reduce grain and help retard oxidation.

Modern Rodinal has metabisulfite and hydroxide in the formula. At the alkaline pH that the hydroxide creates, the metabisulfite is reduced to sulfite. A litre of 1:25 strength Rodinal has about as many sulfite ions as 10 grams of sodium sulfite. This is a fifth as much sulfite as a litre of D76 1+1 or half as much as a litre of Xtol 1+3. This sulfite and the carbonates and citrates buffer the pH and aid in preventing autoxidation. These are very important for storage but how substantially they change between formulae is unclear. The different formulae all are adequately buffered and protected from oxidation at the factory but that is not always a good predictor of their behaviour over time.

Even more important than the formula is the packaging. The bottles or containers need to prevent diffusion of oxygen for the developer to last. The capacity of containers to do this is certain to vary between manufacturers.

My store of Rodinal is from 1998 and works fine with no change in development time. I bought some R09 One Shot in 2011 but haven't opened it yet. Hopefully it will be okay when I get to it.

Marty

 

[p.giannakis]

6 ml in a 300ml tank: Do you mix the Rodinal and distilled water together first in a graduated cylinder and let them sit for a bit to thoroughly mix?

I don't use distilled water, just tap water. I pour the 6 ml in a cylinder and I give it a stir with the thermometer. Then pour in the tank.

 

[ChrisPlatt]

Transferring the concentrate into a well-stoppered glass bottle
might be a good idea, but I'd rather not go to the trouble.

Like the clones IIRC later AGFA Rodinal did come in a plastic bottle.
Maybe current manufacturers failed to copy that formula as well. 😉

Chris

 

[x-ray]

Transferring the concentrate into a well-stoppered glass bottle
might be a good idea, but I'd rather not go to the trouble.

Like the clones IIRC later AGFA Rodinal did come in a plastic bottle.
Maybe current manufacturers failed to copy that formula as well. 😉

Chris

Chris I have a print on my desk that I think you'll like. I matted it and need to find a box to ship it.

If you're concerned about oxidation of anybliquid developer get yourself son Bloxygen. It's available reasonably off Amazon.

 

[airfrogusmc]

I still have two unopened bottles still in the orange box. almost 20 years old. Stored in a dark closet. This is good to know.