A Series 9 47B Deep Blue Color Balancing Filter from Tiffen is a deep blue filter that accentuates haze and fog. It is also used in dye transfer printing, for contrast effects and color separation and tricolor work (lightens blue tones).
Tiffen's ColorCore glass is produced through a process that entails permanently laminating the filter material in between two pieces of optical glass that are ground flat to tolerances of a ten-thousandth of an inch, then mounting them in precision aluminum rings.