ps. to increase the 'two bath' effect you actually have to increase the level of metol (say, to around 6.5gr/L) because how much metol is absorbed into the gelatin depends on the metol concentrate in the A bath. B bath can only develop the metol that is in the gelatin. i have also looked at negatives developed in only A bath then compared to the same negative finished in B bath. B bath does an amazing amount of development. Thornton was right when he said that you only need to develop between 1/2 to 2/3 of the recommended time for A bath only development because B bath really does 'finish' off the negative. the more metol there is ( i have tested up to 10gr/L in 1gr intervals from 7gr ) and all things equal, the more there is an increase in development (A+B) BUT most importantly the 'two bath' effect is increased.