For correction
color temperature of electric bulbs
and for intentional effects

Without Filter

With MC-80B

Shooting with a daylight film under white electric bulbs brings reddish pictures, for the color temperature of home-use bulb is too low. The MC-80A and the MC-80B do correct color temperature to get natural color tones.
The MC-80A normalizes the color temperature of coming rays from light sources of 3200 Kelvin. And the MC-80B rays from light sources of 3400 Kelvin.
The MC-80A is more effective.

For correction
color temperature on
cloudy days
and for intentional effects

Without Filter

With MC-81B

Pictures taken on cloudy days, especially in the shadow, are bluish without warmth.
The MC-81A and the MC-81B do correct this high color temperature.
The 80-A/B can represent natural color tones of healthy human skin, for example.
The MC-81B is more effective and most recommendable for shooting in shadow on cloudy days.

For correction color
temperature mornings and evenings
and for intentional effects

Without Filter

With MC-82A

The Color temperature early in the morning and before sunset is too low and pictures will be reddish.
The MC-82A, a type of "Cool Color FIlters", is indispensable to correct it.

For shooting with tungsten films outside
and for intentional effects

Without Filter

With MC-85A

Pictures taken in daytime outside with tungsten films will be bluish. The MC-85A and the MC-85B do correct it.
The MC-85A is for 3400 Kelvin tungsten films and the MC-85B for 3200 Kelvin.