Thank you both for your help. Ted, isn't then PMK more toxic than DiXactol ? I think (but am not sure) that Pyrocatechol is not as toxic as Pyrogallol. If it is so, then I would find it a good reason not to choose PMK (although I don't want you to think I am trying to advertise Thornton's product). DiXactol may be more economic in its two bath version, if you have many films to develop every time you prepare a quantity of working solution of course. Can't someone prepare his own solution B to avoid paying the price to the manufacturer ? Since it's a simple strong alkali solution, it must not be so hard.(posted 8511 days ago)