An automatic digitizer has been developed that employs a microcomputer‐controlled photosensor to detect and digitize analog curves from strip‐chart paper, drawings, photographs of oscilloscope traces, negatives, etc. The control and data acquisition programs are coded in BASIC enabling real‐time interactive control of the system. Movement of the photosensor is accomplished under program control and is selectable in either a curve‐follower or raster‐scan mode. Use of visible‐LED photodetectors permits curves drawn with different colored inks to be discriminated and separately digitized. The system is simple to use and highly versatile with capabilities that extended beyond curve digitization. In the raster‐scan mode, operation of the apparatus as an optical densitometer is possible enabling detailed image analysis and digital image reconstruction to be performed (e.g., quantitative measurement of intensity distribution and mode structure from photographs of laser output beams.)