A method of modifying an imaging cartridge detachably mountable to an imaging apparatus, the imaging cartridge comprising a cartridge chip, the method including detaching the cartridge chip from the imaging cartridge, the cartridge chip comprising a light emitting device adapted for emitting light in the visible spectrum; and attaching a replacement cartridge chip to the imaging cartridge, the replacement cartridge chip comprising a light emitting device adapted for emitting light outside the visible spectrum.