Method for laser marking of security documents, comprising the steps of: a) detecting graphics information which describes a graphic with different brightness values; b) generating a position control signal and a laser control signal depending on the graphics information, wherein a reference laser light output or reference laser pulse energy is allocated to each brightness value, which is required in order to induce a laser marking with the corresponding brightness value in a security document and, at the generating of the laser control signal, by means of an allocation function a control value is allocated to each brightness value, this control value being provided for producing laser light with the corresponding laser light power in accordance with the reference laser light power or laser pulse energy in accordance with the reference laser pulse energy, c) actuating a laser by means of the laser control signal and radiation of laser light with a laser light power or laser pulse energy in accordance with the laser control signal; and d) time-adjusted actuation of at least one position control device by means of the position control signal, such that the radiated laser light is positioned relative to the security document, such that, by iterative performance of the method steps b) to d) a position-correct marking is carried out of the security document with the graphics comprising the different brightness values, characterised in that at least one calibration step is carried out, wherein, when the calibration step is carried out, the laser control signal is generated with a control value which relates to a brightness value. This value is kept constant during the calibration step. A defined proportion of the laser light is decoupled from the beam path for the purpose of the laser marking, this proportion of the laser light is guided into an absolutely measuring measuring head, a power of the decoupled proportion of the laser light which is guided to the measuring head, or the energy from this which is deposited in the measuring head, is absolutely measured, and, from the measured power or energy of the decoupled proportion of the laser light, the power or pulse energy available for the marking is determined, and the determined power is compared with the reference laser light power, or the determined pulse energy is compared with the reference laser pulse energy, and the calibration is carried by a change in the allocation function if, during the comparison, a difference above a predetermined tolerance threshold is determined. a) detecting graphics information which describes a graphic with different brightness values; b) generating a position control signal and a laser control signal depending on the graphics information, wherein a reference laser light output or reference laser pulse energy is allocated to each brightness value, which is required in order to induce a laser marking with the corresponding brightness value in a security document and, at the generating of the laser control signal, by means of an allocation function a control value is allocated to each brightness value, this control value being provided for producing laser light with the corresponding laser light power in accordance with the reference laser light power or laser pulse energy in accordance with the reference laser pulse energy, c) actuating a laser by means of the laser control signal and radiation of laser light with a laser light power or laser pulse energy in accordance with the laser control signal; and d) time-adjusted actuation of at least one position control device by means of the position control signal, such that the radiated laser light is positioned relative to the security document,