Color separation filters are used in optical systems where the incident light needs to be split into two or more wavelength regions with a high degree of efficiency. It operates using the principle of interference. It is used to selectively pass light of a small range of colors while reflecting other colors. It produces light that is perceived by humans to be highly saturated in color. It is used in color television cameras, color printers & photocopiers, light balancing and control systems.
Colored anodizing involves the immersion of aluminum into a suitable electrochemical solution, which is subjected to a current flow. The electrochemical reaction between the solution and the aluminum forms an oxide film on the surface of the aluminum. The amount of oxide produced can be controlled with great accuracy.