The Tiffen 6.6 x 6.6" 2 Tropic Blue Soft Edge Graduated Filter allows you to specifically add cool blue-green colouration to skies and other bright areas of an image whilst allowing part of the image to remain neutral in colour. The filter's colouration is densest at the edge and fades to clear in the middle, with a soft transition between the density and clear areas. The colour density 2 provides less tropical blue colouration than density 3, but more than the density 1 filter. This filter is 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. It measures 6.6 x 6.6" / 167.6 x 167.6 mm. - Provides deep blue-green colouration to certain areas of the image. - The graduated filter design maintains part of the image neutral, giving a more realistic appearance whilst allowing the sky or other bright areas to take on the density's colour. Specifications