The invention relates to a process for producing pigmented powder coating materials using montanic acid esters, amides or salts as dispersants for the pigments, and to the corresponding powder coating materials. The system includes a power converter comprising a switching stage to conduct an output current in response to switching signals having a defined duty-cycle. In embodiments, the apparatus includes a stage that includes a dose sensor andor an ultra-violet light source. The first lens is accommodated in the barrel.