The Tiffen 6.6 x 6.6" Blue 3 Soft Edge Graduated Filter is a soft-edged graduated colour filter that brings a bluish colour to the image, giving a cooling effect to your photographs. The graduated filter design maintains a neutral part of the image, which gives a more realistic appearance whilst allowing the sky or other bright areas to take on the colour of the density. Density 3 offers less blue tint than the density 4 filter, but more than the density 2.nnTiffen filters are manufactured using ColorCore technology, a process that involves laminating the filter substrate between 2 pieces of optical glass, and grinding it flat to a tolerance of 1/10,000th of an inch. This filter measures 6.6 x 6.6" / 167.6 x 167.6mm.nnn- The blue tint gives a cooling effect to part of the image.n- Soft-edged graduation to transparent in order to maintain a neutral part of the image.nnnSpecificationsnn