I posted the Kalogen formula on APUG some years ago. I recently received a private message concerning its keeping properties. When comparing the original formula with that published in the Dignan Newsletter it seems that the author adjusted the ratio of Metol to hydroquinone without adjusting the amount of sodium hydroxide. The Dignan formula therefore contains too much hydroxide so I offer this modification. Add the hydroxide slowly with stirring until the precipitate just dissolves. At this point stop adding the hydroxide. Then continue on as usual. This method then resembles that used to prepare Rodinal.
I don't use a developer exactly the same as that published. As a starting point I would try a development time for films 1+59 of 5 - 7 m at 20C.
Probably not as long as the legendary Rodinal or HC-110 but still better than other developers I have used. I have had the last inch or so in a bottle last for a year. It got vary dark but still worked. Freshly made and in a stoppered PET bottle it is unchanged now for over 7 yrs. As with Rrodinal preparation it is important that there be no excess hydroxide present.
The Dignan formula therefore contains too much hydroxide so I offer this modification. Add the hydroxide slowly with stirring until the precipitate just dissolves. At this point stop adding the hydroxide. Then continue on as usual. .
I do like that you offer this subjective method here, and have in the past been quite admonitory about using a subjective method for making metaborate
If you add sodium hydroxide until the slurry of borax just dissolves this does not take into account the borax that was already in solution when you started.
For Kalogen and Rodinal the solid IS NOT soluble in water so this kind of error does not occur.
my tongue was slightly in my cheek when I posted, as I hope you realise Gerald, but the fuller explanation it has prompted is invaluable to me as someone who stopped studying chemistry in 1974
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