Rodinal with Phenidone and/or Na-ascorbate

[Sidd]

It would be possible to make a copy of Thornton's 2 bath ,replacing the metol by p-aminophenol, which is about half as active as metol so the negatives would probably come out thin. If acid is added to PaRodinal [danger, heat] a precipitate forms, this is probably p-aminophenol base so one could start with paracetamol/tylenol and make PaRodinal first with a view to making p-aminophenol base from it.

Maybe p-aminophenol base would dissolve in sodium sulfite and maybe the part B would need to be more alkaline than metaborate.

IDK if such a brew would provide any advantage over Thornton's. Metol [methyaminophenol sulfate] is used in preference to p-aminophenol in nearly all developers except Rodinal.

Alan, please guide me with your experience and wisdom regarding the use of phenidone along with Rodinal.

 

[Alan Johnson]

There is nothing in Rodinal that would regenerate oxidized phenidone. It may be that phenidone added would behave like it does in POTA and tend to produce lower contrast. IIRC there are no reports of anyone actually trying this.
The situation is different in Rodinal-Xtol mix as the Xtol contains ascorbate which does regenerate oxidized phenidone.

 

[Sidd]

There is nothing in Rodinal that would regenerate oxidized phenidone. It may be that phenidone added would behave like it does in POTA and tend to produce lower contrast. IIRC there are no reports of anyone actually trying this.
The situation is different in Rodinal-Xtol mix as the Xtol contains ascorbate which does regenerate oxidized phenidone.

Thank you

 

[alanrockwood]

It would be possible to make a copy of Thornton's 2 bath ,replacing the metol by p-aminophenol, which is about half as active as metol so the negatives would probably come out thin. If acid is added to PaRodinal [danger, heat] a precipitate forms, this is probably p-aminophenol base so one could start with paracetamol/tylenol and make PaRodinal first with a view to making p-aminophenol base from it.

Maybe p-aminophenol base would dissolve in sodium sulfite and maybe the part B would need to be more alkaline than metaborate.

IDK if such a brew would provide any advantage over Thornton's. Metol [methyaminophenol sulfate] is used in preference to p-aminophenol in nearly all developers except Rodinal.

I believe that further acidifying p-aminophenol changes it to the acid form (positively charged), which should make it soluble again.

To elaborate, the phenol end of the molecule is acidic and will ionize to the negatively charged form under basic conditions.

The amine end is basic and will ionize to the positively charged form under acidic conditions. Both extremes should be soluble.

In between those extremes the molecule will predominantly exist in the neutral form, which will not be very soluble.

 

[Hassasin]

Rodinal is one of a kind, not just by how old the formula is, but end results as well. And it works very well, well, or well enough with any emulsion ever made. In my mind, one can mix it with anything, lime, tomato juice, black pepper, list is endless. The question will always be simple - why?

if a good photograph cannot be developed with Rodinal from any film, past or present, it was not Rodinal that made it so. There are developers that will change the end result to one’s desire though.

 

[Philippe-Georges]

Rodinal is one of a kind, not just by how old the formula is, but end results as well. And it works very well, well, or well enough with any emulsion ever made. In my mind, one can mix it with anything, lime, tomato juice, black pepper, list is endless. The question will always be simple - why?

if a good photograph cannot be developed with Rodinal from any film, past or present, it was not Rodinal that made it so. There are developers that will change the end result to one’s desire though.

Ha, finally a reasonable response!

And somewhat explaining why I left Rodinal behind after a few years of experimenting (which I started in 2006) on other emulsions than AGFAPAN...

Good luck to you all.