Rodinal formulas

[jim_stewart]

Steve Anchell gives the formula for "traditional" Rodinal as 100gm P-

aminophenol HCl and 300 gm Potassium Metabisufulite per liter. To

this is added a 50% solution of soduim hydroxide solution until the

solution darkens. Photographers Formulary uses 50 Gm of P-aminophenol

HCl and 150 gm Sodium Metabisufulite per liter and then adds a

potassuim hydroxide solution until most of the precipatitate

dissolves. Are these formulas equivalent even though one contains

twice the developing agent of the other?

[chris_waller]

There is also a formulation for a Rodinal-type dev on Ed Buffaloe's site (www.unblinkingeye.com). I can't remember it off-hand but you could check it and see if it compares with the others you found.

[ryuji_suzuki]

If everything is halved including water, then what's the difference?

 

The former formula would result in more than 1000ml of solution because it will require addition of NaOH solution on top of 1000ml solution. I suspect the latter procedure begins with 500ml water and drop in NaOH solution, resulting in half the amount of former.

 

1000ml of Rodinal is a lot of developer, especially because Rodinal is very seldom used in large scale processing. (non-replenishable and requires careful handling)