The Rogue Gels Lighting Filter Kit for Rogue Grid from Expo Imaging makes it easy to bring a more dramatic color sense to all of your photographs using the Rogue Grid. Chose from a variety of Lee filters for reds, yellows, blues, and greens to punch up an image with color, or create mood. Or, use the correction gels to balance your flash to ambient light.Each gel has the LEE name, the gels measured f/stop loss value, and (when appropriate) the corresponding Kelvin color temperature correction and camera white balance icon, all printed directly onto the gel. Stated f/stop loss values are measured using a Sekonic light meter in a controlled test. These values compare the metered exposure of the bare flash with the metered exposure using the Rogue Gels placed over the flash head.