Coral filters are general purpose warming filters which come in increasing amounts of colour temperature correction as the number in the series increases. They are commonly used to produce slightly ""orangey"" skies. Lee graduated colour filters are available with soft or hard transitions from dark to clear. The soft edge is recommended for wide angle lenses and the hard edge is recommended for normal and longer lenses. Lee graduated resin filters are 4 x 6"" (100 x 150mm) x 2mm thick. The 6"" length allows for adjustment of the filter within the holder. Converts 5500°K light to 4255°K.