The 80 series of filters are blue. They are used to balance daylight film under artificial, tungsten or standard (household) incandescent lighting. Lee resin filters are made from lightweight, optical resin & are 4 x 4" (100 x 100mm) x 2mm thick. Filter factor 4 (+2 stop). 80A increases colour temperature from 3200-5500 degrees Kelvin (commonly used with 3200K lamps).