Light — Science & Magic, 6th Edition

METAL 133

Fortunately, most of the direct reection from glass viewed at this angle

is polarized, so we were able to eliminate that reection in Figure 6.27 by

putting a polarizing lter on the lens. e glass is now black.

Remember, too, that direct reection from metal is never polarized unless

the light source itself is polarized. So the polarizing lter did not block the

direct reection from the metal.

A Glossy Background

If the metal is on a glossy surface, it is possible to have the light source in

the image area without the camera seeing it! We call this technique invisible

light. Here is how it works: look back at Figure 6.22, bu ...