The Cokin P Series Red Resin Filter is for digital cameras or film cameras with B&W film. With a digital camera, the red filter can be used in either color mode or B&W mode. For Black&White mode, set the menu on “B&W” position and use it like a Film camera.Red filter must be used for extreme contrasts. By severely contrasting blue sky to almost black, it gives your pictures a dramatic character. By contrast, the clouds becomes more brilliant.