Primarily used in black and white photography, the R1 RED is a strong coloured filter for producing dramatic effects. It behaves as a low-pass filter, passing red, orange, and yellow, whilst filtering out green, blue, and violet. This effectively darkens greens and blues, but lightens reds and browns, resulting in photographs that are amazingly clear. It produces dramatic dark skies with bright clouds and is for good contrast in landscapes which include pale blue skies and oceans. The R1 also works well for architectural shots, especially with red brick buildings and stonework. The R1 Red filter uses Hoya Multicoating to increase light transmission, supress flare and produce sharper images