The Formatt 77mm #47 Blue Filter is a general contrast filter, primarily for use with black and white film. This blue filter is particularly useful for neutralizing the lightening effect of red colored light from tungsten illumination. When used for portraiture, this filter provides more natural looking skin tones. It also accentuates haze, fog, and other atmospheric conditions. In addition to a contrast filter, the #47 filter is used for tri-color separation when used in conjunction with a #29 red and a #61 dark green filter.

There is a 4x filter factor with this filter, requiring an increase of 2 stops for normal exposure. Formatt filters combine high-quality Schott glass with specially formulated CR-39 resin in order to absorb synthetic dyes while still garnering the benefits of optical glass.