The Hitech Color Grad Camera Filter Kit 1- Sunset/ Blue/ Twilight 2- 100 x 150mm is a package of 3 hard-edged color graduated filters: A Sunset filter of density 2, a Blue filter of density 2 and a Twilight filter of density 2.
The Sunset is a multi-color filter blending red, orange and yellow hues; the Blue creates a realistic blue cooling effect; and the Twilight is a combination filter graduated from darkish blue at the top to a pink horizon. It cools the image in a way best suited for creating a late afternoon or early evening twilight effect.
Color graduated camera filters create an effect in the top half of your photo and leave the bottom half alone. They are most commonly used on skylines for landscape work. These hard-edged filters have a defined hard line transition, as opposed to the smooth transition from clear to color provided by the soft-edged type.