Quote Originally Posted by Igor Savchenko View Post
Patrick, your earlier version of this developer had 63 g of Metol and 28.6 g of sodium hidroxide. How did you come to this latest version with decreased amount of Metol and increased amount of hidroxide. Is that to avoid a potential problem of crystallization of Metol in presence of its precipitates undissolved? Do you think that the both versions are approximately equal in activity?
I have had an attack of viral encephalitis and a computer brain failure since then, so I calculated that for every molecular weight of Metol there should be 4 molecular weights of hydroxide, which could of course be either sodium or potassium. 2 moles are used to change the H2SO4 to Na2SO4 and 2 more to create the sodium salt of Metol. I don't remember why I chose 68 grams before, unless it was to give the same number of moles of the Metol base as of p-aminophenol in one of the several formulas for Rodinal. In any case, the 28.6 grams of hydroxide are only enough to neutralize the H2SO4 without forming the Metol salt. I don't have any of the other formula around and am quite happy with the new one.

Metol developers are strange creatures. So is HP5+. I developed two strips of negatives from the same roll of the same subject, one in a 1+50 solution and one in a 1+25 solution, both from thr same batch of concentrate, thinking of course that the 1+25 should give considerably more contrast than the other. I can't see much difference in the results. I seem to remember that D-23 was quite forgiving of errors in development time or temperature.