Originally Posted by
IanG
The version I've given is the only one published by Ilford in numerous of their own publications, (I have at least 6).
The other may originally be from The Photo Lab Index, other books copied their formulae which were riddled with errors. They constantly mis-assume the wrong type of Carbonate, Monohydrated, anhydrous or Crystalline, or made conversion errors. Most US sources of Formulae are less reliable and one of the worst is Suzuki's website. The 3rd Edition of The Darkroom Cookbook is excellent and the only book I'd recommend.
The PQ version of ID-20 is the basis of some commercial Ilford developers, although usually Sodium Carbonate is replaced by Potassium Carbonate & Sodium or Potassium Hydroxide to allow more concentrated solutions.
Find a copy of the Ilford Manual of Photography, best are 1960's editions as they have the PQ developers as well, you'll find ID-62 there, or LFA Mason, Photographic Processing Chemistry, (Mason was head of Research at Ilford)
Ian
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