The Hoya 52mm 80B Hoya Multi-Coated (HMC) Glass filter is blue. It is used to balance daylight film under artificial, tungsten or standard (household) incandescent lighting. You've been given an assignment to do some slide copying on a copy stand. Unfortunately, you only have daylight film and you notice that the copy stand is loaded with 3400K photofloods. Not to worry! An 80B is a strong dark-blue filter that will balance your colors back to reasonable normality. This filter can also be used as a conversion filter for when you are shooting in a room with incandescent light (household light bulbs) and daylight film.