fl-w vs. fl-d filters
 

From a catalog with Hoya filters:

http://www.bhphotovideo.com/product/22895/HOFLW58/REG/161
"An FL-D filter is used when you wish to correct for the greenish tone that appears when shooting daylight film under general purpose fluorescent lighting. An FL-W filter is used to balance daylight film under warm white or white type fluorescent lamps. "


I don't understand the difference between fl-d and fl-w .
Most of my fluorescent lamps are "cool white" or "shop"
lights. Would they require an fl-w filter?

If you are shooting with a good video camera you don't need any of these filters (which are basically for 35mm still photography). Just white balance before shooting.

There are so many types of fluorescent lights available with different color temperatures that those types of filters mentioned are hardly used any more. Many users have mixed the bulb types and the color temps are not consistent. Better to white balance manually or let the camera auto WB if the light sources are mixed (daylight and fluorescent, for example).

Mixed lighting will cause the scene to change colors (sometimes dramatically) if you manually WB and then pan the camera.

Hoya filter values
 

Being an underwater videographer, filters are of great interest to me and I measure them.

The Hoya FL-D is roughly an 81C plus a CC30M.
The Hoya FL-W is roughly an 81 plus a CC60M.

The FL-W has twice the green removal but less color temperature correction relative to the FL-D.

Each manufacturer's flourescent filters are unique. B+W's FL-D, for example is an 81A plus a CC20M. That makes it considerably weaker than the Hoya.