The Cokin P Series Fluorescent Yellow 1 Hard-Edge Graduated 0.1 Filter is designed for use with a Cokin P Series Filter Holder. It can be used to add fluorescent yellow to a hazy or colorless sky. When used to enhance the sky within an image, the desired effect can be applied only to the sky, without any unwanted changes to any other part of the image. The filter is densest at the edge and tapers to clear by the middle, with a hard-edged line of transition between the dense and clear areas. This filter has up to a 0.1 density and reduces light from entering a lens by up to one-third of a stop.

This filter is made of durable, optical resin (CR39), measures 1.6mm thick, and has a grade of 1. A grade of 2 is also available where this filter type's effect becomes approximately twice as strong with each grade number increase.

Cokin color graduated filters are color-toned in one half of the filter and have a smoothly graduated transition into the clear portion. Colored and clear image portions can be brought into the desired position by adjusting the filter in the holder. Most Cokin graduated filters are available in two densities 1 & 2, with #2 being darker. Cokin color graduated filters can also be combined with other Cokin filters. Two color graduated filters rotated 180 degrees to each other allow a composition of colors to fade into each other.

This filter measures 85 x 85mm and fits the Cokin P series holder.