81 series are color corrective filters that 'warm' bluish tones. They are avaible in several strengths (A, B, C & EF) with 'A' being the mildest warming effect. Available in all popular sizes.
The Hoya 72mm 81B Hoya Multi-Coated (HMC) Glass filter controls the bluish coloration that affects daylight film. It can also remove excessive blue from the effects of electronic flash.
An 81B filter will replace even more yellow than an 81A and bring skin tones back to a more appealing level....
These are color conversion filters for the use of daylight type color films with artificial light source. 80A increases the color temperature from 3200°K to 5500°K for the use with 3200°K lamps. 80B increases the color temperature from 3400°K to 5500°K for the use of photoflood lamps. 80C increases
These are light balancing filters used to decrease the color temperature slightly for a warmer (redder) tone. Corrects the tendency toward bluish tones. For example, the 81A should be selected when using tungsten Type B color film (3200°K) with photoflood lamps (3400°K) These filters can