The Tiffen 5.65 x 5.65" Complement Blue 1 Glass Filter is part of a series of special effect filters intended to balance the overall tone of your image. Graduated Complement filters provide the needed color balance to half of your image by filling in a "complementary" color. Tiffen Complementary filters are designed to be used together with a Color-Grad filter in this manner, or to add a bit of color interest on their own.
A beautiful sunset, a serene ocean and a wooden pier with an old fisherman standing alone at the end of the dock. What a photo it is! So, you throw on your Graduated Twilight filter and the vast sky dominating the image gets "bumped" up in color and contrast. But what about the foreground? The Graduated Complement filter allows you to "share" some of that "bump" with the all-too-often forgotten foreground. Thus, the entire image benefits. The overall tint your photo now has makes it an even better photo.