The Formatt 6 x 4" Combination Light Balancing 81EF/Neutral Density (ND) 0.9 Schott-Desag B270 Crown Optical 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.
Neutral Density (ND)
ND filters appear gray 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.
Formatt, a company with three generations of professional filter-making experience, produces every filter to the highest technical standards. The finest materials, together with state of-the-art production technology, have resulted in a standard of optical excellence unmatched anywhere else.