Lee 80D Blue Cooling/Temperature Conversion Filter 4x4" Resin.
•80 series dark blue filters are used for major cooling effect to color tone. • They are also engineer to correct tungsten artifical light (usually 3200 to 3800 Kelvin) to daylight (5500 kelvin) allowing the use of daylight film with artifical (tungsten) light.
•••@80A converts light from 3200K to 5500K for use with household lamps; requires +2 stops. •••@80B converts light from 3400K to 5500K for use with photofloods; +1 1/3 stop. •••@80C converts light from 3800K to 5500K for use with clear flash bulbs; +1 stop. •••@80D converts light from 4200K to 5500K for mixed lighting (ex:house lamps + window light); +2/3 stop.