Kodak 3x3" (75mm) #24 Red Wratten 2 Gel Filter - This red filter is ideal for strong contrast improvement since it absorbs green and blue completely and enhances red. Slightly less in strength than a standard #25, clouds are dramatically improved almost to the mood of a thunderstorm. It is more effective in cutting through haze, and moonlight effects are easily accomplished. Those interested in infrared photography should use a #25 filter.
Most Kodak gelatin filters are available in 3 x 3" (75 x 75mm), 4 x 4" (100 x 100mm), 6 x 6" (150 x 150mm), and 14 x 18" (350 x 450mm).
Wratten 2 Improvements
Easier to handle
Color consistent today, and 6 months from now as well
Wratten 2 Optical Filters are less sensitive to humidity, less prone to static cling