In the conventional methods for the preparation of printing pastes containing couplable diazonium compounds, liquid bases, sodium nitrite and phosphoric acid are incorporated separately in succession in the thickener or they are each prepared as separate thickeners and then combined with stirring only when they are used. Such measures are relatively complicated and are therefore considered as a disadvantage in practice. If the acids customary for the diazotization are used, there is a further risk that the fixation by steaming of the reactive dyes printed in addition to the diazo components will be impaired.This situation considered problematical by persons skilled in the art can be remedied by using liquid water-based preparations of diazotizable amines which, in addition to the amine, simultaneously contain the amount of acid necessary for its diazotization in the form of, preferably, phosphoric acid. These preparations according to the invention only have to be stirred into a thickener containing a nitrite in order to prepare ready-to-use printing pastes.