This paper is a status report covering the development of detector-based standards for optical calibration. It briefly treats, in historical perspective, the philosophy and technology underlying the use of detectors as standards and assesses the impact of recent technological developments. Next, the development and operation of the Electrically Calibrated Pyroelectric Radiometer (ECPR) are described, and the methods used to characterize this instrument are outlined. Finally, we review the present capabilities of the ECPR and summarize some of the measurements to which it has been applied.