The lamp has lighting unit (1) having colored LEDs that emit light in the basic colors of a color system on product display area (N). The directional sensors (2) detect light spectrum reflected from the area and/or objects on the area. A control unit (3) determines dominant color based on the sensor result. The control unit drives the LEDs to emit a modified standard light spectrum in which the proportion of dominant color is intensified for emphasizing the dominant color.
