Conrad, Anchell and Troop recommend substituting 150g/L sodium metaborate (Kodalk) for potassium carbonate. I've tried it and it does yield slightly smoother tonality, while minimally reducing the biting sharpness of the original formula.(posted 8272 days ago)I've used 8ml of 10% sodium hydroxide /L (instead of 75ml of 10% potassium carbonate) of working developer as the B component and it yields smoother tones and finer grain than either of the above options, and with very high sharpness too.