Sunlight, daylight, incandescent, fluorescent, and other artificial light sources all have color characteristics that vary significantly. Filters give you better images by adjusting for these light variations.
Film and video are rated for a particular color temperature such as that of daylight or tungsten light. Filters are used to correct differences in color temperature between the recording medium and the light source.
80 Series - Get the right colors with daylight film when shooting indoors, with tungsten lighting, and without a flash.
80A: Balances daylight film for use with most standard tungsten lighting, studio lighting and copy stand lighting
80B: Balances daylight film for use with photo flood lamps
Filter Conversion Exposure increase:
80A (3,200 to 5,500 K) 2 stops
80B (3,400 to 5,500 K) 2 stops