Color and Polarization Light and Reflection Color and Polarization

Colors Different wavelengths of visible light have different colors. Objects have colors because they reflect certain wavelengths of light We see the reflected color When no light is reflected, objects appear black When all wavelengths of light are reflected equally, objects appear white

Colors

Colors Colors may be added or subtracted to produce other colors Additive primary colors: red, blue, green Combining two if these colors produces one of the additive secondary colors: cyan, yellow, magenta Combing all three additive primary colors produces white Complementary color – the color of light needed to add to another color of light to produce white light

Colors

Colors Subtractive primary colors: yellow, cyan, magenta Also called primary pigments Combining two if these colors produces one of the subtractive secondary colors: red, blue, green Combing all three subtractive primary colors produces black Black is the absence of color

Colors

Polarization of Light Linear polarization – the alignment of electromagnetic waves in such a way that the vibrations of the electric fields in each of the waves are parallel to each other When the vibrations are in random directions the light is unpolarized Typical light To polarize light there needs to be some sort of filter Transmission polarization – only light that can pass through the filter (polarizer) continues The rest is either absorbed or reflected

Polarization of Light Transmission axis – the axis that the filter lets light pass through A polarizer can be used to determine if light is polarized and in what direction by rotating the polarizer When the plane of polarization is parallel to the transmission axis the light is brightest When the plane of polarization is perpendicular to the transmission axis, no light passes through

Polarization of Light

Polarization of Light Light can also be polarized by reflection and absorption and scattering Similar to transmission polarization with a reflecting or scattering surface acting as the polarizer

Polarization of Light