This bw 77mm mrc uvir 486m interference filter has a completely colourless glass carrier coated with a number of extremely thin partially reflecting layers with precisely computed thicknesses similar to mc coating the bw filter 486 does not block by means of absorption but by interference of the unwanted uv and ir radiation that is repeatedly reflected between these layers affecting the wavelengths on both sides of the visible spectrum with a steep cut off it is used mainly on digital