Glare can be reduced on an inspection surface by using

• A. Visible light
• B. Screens
• C. Polarized light
• D. Spectral light

Answer: (C)

Polarized light reduces glare by filtering the polarized component of reflected light. When light strikes a smooth, shiny inspection surface, the reflected glare becomes polarized in a specific direction. A polarizing element—either in the illumination path or in front of the observer’s eye or camera—blocks light polarized in that orientation while still transmitting the component that carries the surface details. By rotating the polarizer, you can minimize glare: at the right angle, most of the glare is absorbed, and the underlying features remain visible. This technique directly suppresses the specular reflections that cause glare, making defects easier to see. Other approaches like unpolarized visible light, screens, or purely spectral lighting don’t selectively filter glare in the same way.