ABSTRACT
The use of CCD detectors for BVRI photometry is discussed. For the adopted filter system and detector linear transformations to the standard system with residuals, expressed as rms deviation per star, of only 1 or 2 percent, are determined. A region is defined in open cluster M67 where stars covering a (B-V) color-index range from -0.1 to +1.3 are calibrated at B, V, R, and I wavelengths. This region is useful for calibration of the system's sensitivity. Where overlap exists with previous observers, the magnitude zero points for M67 stars agree at better than the 1 percent level.