Reviving this thread with a related question....

I noticed the recipe attached to this thread includes a "Agfa 80" recipe. The main difference between the D-19 and Agfa 80 is that Potassium Carbonate replaces Sodium Carbonate in the Agfa 80.
I was just wondering what the effect of this may be?

I'm asking as I was about to mix my own D-19 when I realised I was low on Sodium Carbonate but had plenty of Potassium Carbonate.