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Old 25th July 2020, 08:07 AM
Lostlabours Lostlabours is offline
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Quote:
Originally Posted by Ami H View Post
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 (?)

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
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