When using the PE530 with a monochrome (black-and-white) camera or other sensors, together with a broadband light source (such as the sun), the resulting spectral response replicates in the same proportions what the human eye will see, closely matching the CIE 1931 photopic luminosity curve. This is highly useful in applications requiring accurate lux, lumen or cd/m2 readings. Photopic response filters are also used in conjunction with ambient light detectors, for example photoelectric sensors used to control when infrared LED lighting is brought into use in day-night imaging applications. They are also used in automatic control of display backlight brightness and ambient light sensors used in mobile phones to appropriately dim or brighten a device’s screen.