[Leica] Adox ATM49

[benedenia at gmail.com (Marty Deveney)]

John -
Stick with whatever suits you. ?Your photos shows awesome process
control, so stick at it. ?Any of the Atomal formulae are expensive
here.

>So why Sodium Sulfite at 100 g/l and Oxyethyl-ortho-aminophenol?  I would
>think you could cut back to 40-50 grams/l which would increase actuance I
>think.  Unless the Sulfite also is needed as an accelerator for the
>Oxyethyl-ortho-aminophenol, which is likely.  The reduced sulfite would
>also increase actuance by allowing the pyro to proportionally stain the
>density.

The sulfite is probably there to prevent oxidation of the
0-aminophenol, which isn't very stable.  In my experience all benzene
diols including catechol, pyro, hydroquinone and others stop staining
at between 5 and 10 g/L sulfite.  But both o-aminophenol and sulfite
prevent staining.

>The Sodium Metaphosphate is likely used to increase the rate of
>hydroquinone developement and give maximum contrast.

Metaphosphate is probably there to sequester divalent anions.

>The potassium bromide here would then be a restrainer, which seems
>unnecessary as the sodium metaphosphate isn't that caustic?  Not as much as
>Sodium Hydroxide at least.  If fog is a problem then perhaps a less caustic
>sodium would work.

The restrainer is needed as this has an almost full load of sulfite
and carbonate.

>Interesting formula to play around with.  I'll have to see if I can get
>some of the aminophenol, and Sodium Metaphosphate, both not the usual fare.

Yes, interesting - but I still think way too complicated.

Marty