The Kodak Wrattan 80 Series of filters are blue. They are used to balance daylight film under artificial, tungsten or standard (household) incandescent lighting.
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).
Note:
The 81 series is available in grades from 81 through 81EF with 81EF having the warmest effect
80 Series Color Conversion Chart
80A increases color temperature from 3200-5500 Kelvin (commonly used with 3200K lamps)
80B increases color temperature from 3400-5500 Kelvin (commonly used with photoflood lamps)
80C increases color temperature from 3800-5500 Kelvin (commonly used with flashbulbs)
80D increases color temperature from 4100-5500 Kelvin (commonly used to remove extreme orange or red)
Wratten 2 Improvements
More rigid/durable
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
Fingerprint removal is also easier