The influence of operating conditions such as temperature, concentration of electrolyte and applied voltage, on the effectiveness of the additive light green in a phosphoric acid bath, on film porosity and current density during anodizing of pure aluminum has been investigated using electrochemical methods. X-Ray fluorescence was used to determine the incorporated amount of phosphorous in the anodic oxide. The principal factor which affects the action of this additive seems to be the applied voltage, while the other parameters have a much smaller influence.