Thank you both for responding to my enquiry about amidol.
The recipe Ron quotes is the standard paper recipe. It is stunningly effective
especially when a liberal dose of potasium bromide is added which will warm up
paper tones. It also improves the keeping quality if about an eighth of the
amount of sulphite is replaced by potassium metabisulphite.
I know that when I placed a sheet of Kentmere Classic Art in the developer it
came up in the same wat as a platinum print would in potassium oxalate. The
print in terms of tonal range and separation of tones within narrow ranges was
almost enough to bring me back to silver gelatine.
But for film it is better to use the acid amidol recipe.The recipe is from the
Illiffe Dictionary of Photography fourteenth edition. A dictionary I read from
cover to cover like a novel.
This is a translation from imperial to metric;
Boiled water (important) 570 ml
Sodium Sulphite (cryst) 43 g
Sodium Sulphite lye 35 ml
Amidul 4 g
potassium Bromide 0.3 g
For the lye
Add 15 ml of sulphuric acid to 200 ml of water and then stir in 115 g of sodium
sulphite until it is dissolved.
The seventeenth edition of the dictionary says that ' it is the only common
developing agent that will develop in acid solution'.
'N' for both is about ninety seconds.
Keep your fingers out of it unless you want to look as if you smoke sixty a day.
Both developers without the bromide go off in about an hour.
Your Jacobson formula is only for those who drink very weak tea.
As I do very little silver gelatine printing I do not use PMK which I know is
good for its purpose but it stains the film which rules it out for contact
processes.
The downside of amidol is that is expensive, difficult to get hold of, goes off
quickly and stains your hands.
The nearest developer from a bottle is PQ Universal.
Essentially we are dealing with plate developers.
I would be interested to hear others experience.