This is a common mixing practice with developers containing Metol and Sodium Sulfite. Measure out the total Sulfite, take a "pinch" of it (between your thumb and index finger - same as you would do when a cooking recipe calls for a "pinch" of whatever) and dissolve it. Then add the Metol and dissolve. Then add the rest of the Sulfite.
The reasoning is that Metol will not dissolve in a Sodium Sulfite solution containing more than a small amount of Sulfite. But adding a small amount of Sulfite before the Metol helps scavenge some Oxygen so that the Metol is better preserved while you are dissolving it, before the rest of the Sulfite goes in and "stabilizes" the Metol solution.
Having said all this, the "pinch" is usually the amount called for when mixing say a litre of developer stock - which would usually contain somewhere between 30-100g Sodium Sulfite. Given the 12 litre mix in Bob's recipe above, and the relatively high 12g/litre concentration of Metol, I wonder if the "pinch" of Sulfite has any appreciable effect.
Last edited by Michael R 1974; 01-22-2013 at 11:02 AM. Click to view previous post history.