Dot Area Meter is used to measure halftone dot area on a printing plate accurately. It includes an illumination source for providing light having a first range of wavelengths. It reads positive and negative dot area directly on offset litho plates. It is used with either computer-to-plate or conventional plate exposure systems. It permits evaluation of exposure intensities, calibration of plate setter and operation of vacuum hold-down. It has serial output port for interface with computer or data network. It operates on rechargeable battery. It includes calibration plaque, 115V or 230V charger and battery saver, and attractive carrying case.