A label modification unit may receive a label modification input that indicates a label modification associated with content being written to a label or erased from the label. The label modification unit may identify an area of the label that is associated with the label modification according to the label modification input. The label modification unit may determine, based on a size of the area, a spot size of a light beam that is configured to be emitted by a laser printhead to modify the content within the area. The label modification unit may determine, based on the spot size and the content, an optical path configuration for the laser printhead. The label modification unit may operate the laser printhead according to the optical path configuration to write the content to the area or erase the content from the area.