Gradual filter which eliminates the greenish tones of shooting under fluorescent lighting such as strong white tubes. It is recommended to place the colored part of the filter on the light source. Their color gradually fades out so the boundary between the colored and transparent sections will not become apparent even with the lens aperture stopped down.
FLW (A036) corrects the lighting from florscent "white" bulbs.
FLW (A138) is the graduated version for mixed lighting.
FLD (A046) corrects the lighting from florscent "daylight" bulbs.
FLD (A139) is the graduated version for mixed lighting.
The Cokin A System comprises a complete range of COKIN filters for lens adaptor rings diameters 36 to 62 mm and Hasselblad Ring B50 as well as numerous dedicated accessories. The ”A Series” is recommended for focal lengths 35mm & greater.
For more information about, Cokin Gradual FLD Filter A Series A139 .