There's stable Phenidone derivatives, something that all Kodak chemists were well aware of, particularly as one senior research scientist helped edit LFA Mason's book "Photographic Processing Chemistry, and that included the section on Phenidone & the derivatives.
Originally Posted by Michael R 1974
Sure some developing agents in the Phenidone class are slightly better than others, the Dimezonnes are placed in this class as are other Phenidone derivatives. There's a deliberate attempt in these threads to deride Phenidone when it's been in use commercially for about 60 years with none of the issues.
In terms of shelf life between the Phenidone derivatives and thei Dimezones, is not huge difference like a few weeks or months instead of 2 or 3 years and that's being overlooked.
Interesting that PQ developers have a far better shelf life than MQ developers and in fact was why many manufacturers switched to them, that put's things into a better perspective.
There's a lot of references to old data and books which refer to the original Phenidone which was unstable in highly alkali solutions and so never went int commercial production. Mason of Ilford refers to this instability so it's not something Ilford didn't address
Last edited by Ian Grant; 01-08-2013 at 06:43 PM. Click to view previous post history.