Abstract: A photographic aqueous processing solution containing at least one solid compound that has a maximum solubility therein corresponding to a desired operating level, which solution is kept in equilibrium with the solid form of the compound, thus maintaining its concentration at the desired level without the need for a replenishing system.

Abstract: A photographic aqueous processing solution containing at least one solid compound that has a maximum solubility therein corresponding to a desired operating level, which solution is kept in equilibrium with the solid form of the compound, thus maintaining its concentration at the desired level without the need for a replenishing system.

Abstract: A photographic aqueous processing solution containing at least one solid compound that has a maximum solubility therein corresponding to a desired operating level, which solution is kept in equilibrium with the solid form of the compound, thus maintaining its concentration at the desired level without the need for a replenishing system.

Abstract: The present invention relates to a method of synthesizing a 2-substituted nitrogen containing compound having a formula (I): ##STR1## by reacting a hydroxylamine of formula (II); ##STR2## or a nitrone of formula (III): ##STR3## with a compound of formula (IV); ##STR4## thereby to form an intermediate compound, and thereafter causing or allowing said intermediate compound to undergo a pericyclic sigmatropic rearrangement reaction to form the compound (I); wherein X is a nucleofugal group, Y is selected from O,S,NH,NR.sub.5 and CR.sub.6 R.sub.7, R.sub.1 is a group which directs the reactivity of compound (II) on to the oxygen atom and R.sub.2 to R.sub.9 are each a substituted or unsubstituted aliphatic, aromatic, heteroaryl or cyclic group or hydrogen which is substantially inert or is protected during the reaction.