Abstract: Modulation of the edge erase lamps in a copier/duplicator/printer to record visual data in the normally unused margins of a copy/duplicate/print. Numerical information can be recorded by a controlled switching sequence of the lamps normally used for edge erasing on electrophotostatic type copiers (or duplicators or printers). Turning off an edge erase lamp causes a dark streak near the margin on the copy in line with the lamp so switched off. By selectively turning off and on combinations of a plurality of edge erase lamps, visual data such as numerals can be written in the margins while copies (or duplicates or prints) are being produced.