The Kodak 3 x 3" Carbon Neutral Density (ND) 0.5 Wratten 2 Gel Filter has several uses and offers the possibility to achieve otherwise unachievable results. ND filters appear grey and reduce the amount of light reaching the film. They have no effect on color balance.
Most Kodak gelatin filters are available in 3 x 3" (75 x 75mm), 4 x 4" (100 x 100mm), 6 x 6" (150 x 150mm), 14 x 18" (350 x 450mm) and 4 x 12" (10.2 x 30.5cm).