Electro-optical devices present a much more complex testing problem than pure optical systems. An optical system is normally fixed and passive making it independent of light level used in testing. An electro-optical device, however, may have gain, wavelength conversion, and electronic or mechanical dynamics associated with their mode of operation. In addition, these systems may use direct imaging, array scanning or line scanning techniques in their image display system. Image testing, therefore, may have to be performed at low light levels in high gain systems to prevent damage to the photocathode. The device may have to be gated in synchronism with the display. For systems with automatic brightness control, the operating point of the imaging test must be carefully defined in order to get accurate and repeatable data. All of these factors must be considered to get valid data on the image quality of electro-optical devices. This paper will cover the generic system types and typical testing configurations for performing these measurements.