The invention relates to an alkaline developer for irradiated radiation sensitive compositions, which developer is based on water, comprises at least one alkaline reacting silicate and has a pH of at least 11, characterized in that the developer comprises at least a non-ionic surfactant, wherein the hydrophobic part is an aryl group having in addition to the hydrophilic part at least two substituents different to hydrogen, and the hydrophilic part is a polyethyleneoxy group with at least 6 ethyleneoxy units. The developer leads to less depositions in the developing apparatus and on the processed printing plates and has an increased sedimentation stability.