80B increases the color temperature from 3400°K to 5500°K for the use of photoflood lamps.
They have a filter factor of 2 and require 1 f-stop of additional light.
All light sources, natural or artificial, have characteristics that affect color rendition on film. Most films are engineered for either daylight or tungsten photofloods which are rated respectively at 5500K degrees (daylight) and 3400K degrees (photofloods) on the Kelvin (K) color temperature scale.
Color correcting filters are designed to 'warm', 'cool' and/or correct for the many variations of lighting you might encounter.
All filters have a 'filter factor' which is a measurement of the light it absorbs. Cameras with internal metering (through the lens) will automatically adjust the exposure. With external or hand held meters you must allow for this factor.
Note: Modern strobes (flash) are approximately 5500K and will 'overpower' household lighting. With daylight film, no filtration is necessary unless special effects are desired.