NUANCES C-PL filters are made from high resolution Schott B270i glass. Circular polarizing filters are used to reduce the reflections of non-metallic surfaces (windows, water, etc.) and strengthen the colour density of the sky and/or foliage by absorbing reflected light. They can also accentuate details like clouds and make photos richer, with deeper tones. The effect cannot be reproduced by touch-up software. Absorption = 1 x Diaphragm