The Tiffen 86mm Combination Light Balancing 81EF/Neutral Density (ND) 0.9 Glass Filter combines the effects of an 81EF Light Balancing filter with a Neutral Density filter.
An 81EF filter (the strongest in the 81 series) will more than replace the yellow missing from the image and place all skin tones on a distinctly "warmish" level. You might even consider using an 81EF at the beach to make a hot scene even "hotter".
It's Autumn. The clouds are low hanging and the sky is "patchy blue". You've gone for a ride upstate to the mountains and the light in open shade is bluish. A photo taken of your girlfriend with daylight balanced film leaning against the side of a barn will yield bluish tones that she might not find particularly flattering.
The 81 series (81A, B, C, D and EF) allows you to choose how much warmth you wish to replace in the image.
Tiffen makes the 81 series of filters in many sizes to accommodate the many uses this filter has. This filter can be used by the pro and amateur alike, weekend photo warrior or pro cinematographer and must be considered an essential addition to any photo arsenal.
Neutral Density (ND)
ND filters appear grey and reduce the amount of light reaching the film; They have no effect on color balance. They are very useful when you want to shoot high speed film outdoors on a very bright day.
Determining which neutral density filter yields ideal results for any given lighting situation takes knowledge, experience and a collection of such filters. Speaking generally, the 2-stop value (ND 0.6) effectively compensates average situations.
Tiffen, a leader in the filter industry, proudly makes its filters in the USA and backs up its products with a solid 10-year warranty.