Sunpak 52mm Red Filter #25

The most popular of the contrast filters for black and white photography, red creates dramatic effects by brightening red and orange while darkening blue and blue-green in sky, water and architectural scenes.

With underexposure, the red filter may be used to simulate a moonlit scene at midday.

With infrared film, the filter gives extreme contrast to skies, turning foliage white and cutting through fog and haze.