Quote:
Originally Posted by Ami H
Hi, just out of curiosity i thought i had read this formula in the latest edition of the film developing cookbook (2nd edition).
On page 127 there is 2 potential formulas for Acuspeed (FX20) dated 15th June 1967 from Crawley's notebooks.
Code:
Acuspeed (FX20) 15th June 1967
Formula A (g) Formula B (g)
Sodium sulfite anhydrous: 70 77.5
Sodium carbonate anh 22.5 25
Sodium metaborate 22.5 25
Glycin 22.5 25
Hydroquinone 12 13.3
Phenidone 1.25 1.4
Sodium bisulfite 1.25 1.4
Potassium hydroxide 10 11
Sodium hydroxide 10 11
Potassium thiosulfate (powder) 5.25 6
Potassium bromide 1.25 4
Water to make 1 litre
We have not included the solvents Crawley used so this concentrate may have to be made up at for example 1/2 strength
pH between 10.9 and 11
Dilution 1+9 (?)
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Those are extremely bizarre formula, Potassium Thiosulphate in a developer, only in reversal processing. Also at 1+9 there's insufficient Hydroquinone.
Crawley wouldn't use Sodium Bisulphite it's an unstable compound only used as a Lab reagent, he would use Sodium Metabisulphite but not with Hydroxide and Metaborate. Sodium Metabisulphite forns Sulphite instantly in the prescence of Hydroxirde or Carbonate.
Fiction I fear not facts.
Ian