Abstract: This method uses electronic measurement of color values in aerial infrared photographic transparencies to analyze the growing condition of a crop. A series of infrared photographs are taken during the growing season, and average color values from the resulting image are plotted and compared to optimum growing conditions. Electronic measurements are made of color densities about the total field area as represented on each photographic image. Each measurement is corrected to eliminate exposure variations in the images due to photographic factors, weather factors, lighting and film conditions, and the date and time at which the photograph was taken.