Product DescriptionThe  Tiffen Graduated Blue Glass Filter Âcan make a run-of-the-mill sunrise or sunset into a memorable image. This unique filter adds spectacular color to one half the photo while leaving the other half untouched. If you like shooting landscapes in the morning or at dusk, make them into breathtaking studies. Not only will  it add color but it does so with a subtle and extremely gradual transition between the two halves of the filter. Soft/hard indicates the degree of transition. Horizontal/Vertical indicates the direction of the graduation. Add color selectively while leaving the rest of the scene unaffected Half color, half clear with a graduated density transition for smooth blending into the scene Available in a rainbow array of colors and Neutral Density filters Used in combination, with one affecting the upper half of the image, the other affecting the lower half ColorCore Technology Tiffen filters are manufactured using ColorCore technology, a closely guarded proprietary process that entails permanently laminating the filter material in between two pieces of optical glass that are ground flat to tolerances of a ten-thousandth of an inch, then mounting them in precision metal rings The ColorCore process allows Tiffen to control the color and density of their filters, and the characteristics of special effects filters with much greater accuracy than typical dyed-in-the-mass filters, which usually exhibit color and density variations Superior Quality Top Hollywood motion picture studios rely on Tiffen filters for their multimillion-dollar productions Superior quality and design make Tiffen the overwhelming choice of moviemakers, professional photographers and even NASA Tiffen has also been awarded an Emmy, from the Academy of Television Arts and Sciences, for its engineering excellenceAmazon.comExposing for the foreground will produce a washed-out, over-exposed sky. Exposing for the sky will leave the foreground dark and underexposed. This filter allows more sky detain while properly exposing the foreground.