Hello

I was found two different formula for EZ-Rodinal

1st early version found here:

http://www.apug.org/forums/forum37/2...titutes-4.html
Start with 700 ml water at room temperature.

Add 170 grams of anhydrous sodium sulfite, 14 grams sodium hydroxide, and stir till dissolved. Warming it a little won't hurt. Add 40 grams p-aminophenol (not the hydrochloride). It will not all dissolve. Add water to make 1 liter. When you transfer from the mixing vesel to storage, do not filter out the sediment. Use it like AGFA Rodinal.

2nd (latest) version from EZ-Rodinal article

http://www.apug.org/forums/forum223/...z-rodinal.html
To 400 ml water, add:

85 g anhydrous sodium sulfite.

40 g p-aminophenol base.

Stir well. Add

13.8 g sodium hydroxide or 19.2 g potassium hydroxide.

Add water to make 500 ml.

rewrite this formulas for 1l concentrate:

**1st version**
Sodium sulfite 170g

p-Aminophenol base 40g

Sodium hydroxide 14g

Water 1l

**2nd version**
Sodium sulfite 170g

p-Aminophenol base 80g

Sodium hydroxide 27.6g

Water 1l

easy to see that 2nd version have twice amount of p-Aminophenol. Compared to known Rodinal formula from

http://www.digitaltruth.com/data/rodinal.php
p-Aminophenol Hydrochloride 50 g

Potassium Metabisulfite 150 g

Sodium Hydroxide 100 g

Cold water to make 1L

while we mix all ingredient reaction describes next formulas

K2S2O5 + 2NaOH = K2SO3 + Na2SO3 + H2O

C6H4OHNH2.HCl + 2NaOH = C6H4ONaNH2 + NaCl + 2H2O

MW(C6H4OHNH2.HCl)=145.59, so formula contains 50/145.59=0.343M of p-Aminophenol Hydrochloride. For PAP base MW(C6H4OHNH2)=109.13. and amount of base will be 109.13*0.343M=37.48g. This is near the 50g in 1st version of EZ-Rodinal.

Amount of K2SO3+Na2SO3 is 1.35M. We need 1.35M*MW(Na2SO3)=1.35M*126.04=170g of Sodium sulfite. This is also same as in 1st version.

So my question - is the 2nd version of EZ-Rodinal correct?