A Tiffen FL-B filter is used to correct colour balance when shooting with tungsten film under fluorescent lighting. This filter is made of glass and measures 100 x 140 mm (4x5.65") x 4 mm thick. NOTE: The FL filter series alone does not always guarantee 100% correct colour balance when shooting under fluorescent lighting. These are general-purpose filters intended for moderate correction and will not necessarily provide perfect colour rendition on their own. An FL-W filter is used to balance daylight film under warm white or white fluorescent lamps. An FL-D filter is used when you want to correct the greenish cast that appears when shooting with daylight film under general-purpose fluorescent lighting. Fluorescent lamps burn at many different temperatures and often require more demanding filtration for accurate results. For specific filtration and professional use, it is strongly recommended to use a colour temperature meter along with colour correction filters (e.g. CC30M) when shooting under fluorescent lighting. This is the only proven method to achieve exact colour correction. - Pleasant skin tones under fluorescent lighting without flash - True-to-life colour rendition - Essential in any environment where the ambient light source is fluorescent Specifications