Quote Originally Posted by Michael R 1974 View Post
(...) the developer composition specified in PH2.5-1972 is identical to the one in PH2.5-1979 except for a weaker carbonate alkali system: 1.5g Sodium carbonate (anhydrous) and 1.0g Sodium bicarbonate, with a specified pH of 9.4 +/- 0.2 (...)
Thanks for this observation. In order to avoid mistakes, could you give the full formula ?