Glycin and Carbonate

[Raghu Kuvempunagar]

It is well known that Ansco 130 developer stock solution lasts for a long time (6-12 months) despite containing good amount of Carbonate. Is the long shelf life of Ansco 130 due to the fact that it contains Glycin? If so why does Crawley's FX2, another Glycin based developer (that shares Sulphite and Metol with Ansco 130) keeps Carbonate separate as part B? Can FX2 stock solution be brewed with Carbonate in Part A like Ansco 130?

 

[Alan Johnson]

With the glycin carbonate sulfite developer GSD-10 I found the same as this poster:
https://www.flickr.com/groups/1447120@N21/discuss/72157666384558641/
After a few months it deposits flakes.
Hence, IMO the 2-solution FX-2 is better .

 

[Raghu Kuvempunagar]

@Alan Johnson: interesting phenomenon! I'm guessing these flakes are precipitated bicarbonate which got produced due to the absorption of atmospheric CO2 by the carbonate rich stock solution. Did the flake containing stock solution loose its strength due to reduction in pH?

 

[Alan Johnson]

The GSD-10 was stored in a 3/4 full sealed glass bottle so it was unlikely to be affected by oxygen or CO2 from the air when the flakes were found. I threw it out without further testing. I would guess that in 1960 Crawley may have got the 2-solution idea from the old timers who developed lantern slides with glycin.IDK what chemistry is involved.