Optics and Color

Optics is the study of light and its interaction with matter. Light is a form of electromagnetic radiation, and the portion the human eye can detect, the visible spectrum, occupies only a narrow band of wavelengths. Beyond the red end of this band lies infrared radiation, and beyond the violet end lies ultraviolet, both invisible to the eye but otherwise sharing the same physical nature. White light from the Sun is a mixture of all visible wavelengths.

When light passes from one medium into another it changes speed and bends, an effect called refraction. Because different wavelengths bend by slightly different amounts, a glass prism spreads white light into a band of colors. The same dispersion in raindrops produces a rainbow, with red appearing on the outer edge and violet on the inner. The color an object appears depends on which wavelengths it reflects and which it absorbs, and atomic spectra reveal the specific wavelengths that particular elements emit or absorb.

Color can be described and reproduced using models. The RGB model mixes red, green and blue light in varying amounts to create a wide range of colors and is used in displays and digital imaging. Optical technology extends these principles to practical systems, including fiber-optic cables that guide light through thin glass strands by total internal reflection, carrying information over long distances using optical transmitters and receivers.

Frequently asked questions

What is the visible spectrum?

It is the range of light wavelengths the human eye can detect, spanning from red at the long-wavelength end to violet at the short-wavelength end.

Why does a prism produce colors?

A prism refracts light, and because each wavelength bends by a slightly different amount, white light is separated into its component colors, an effect called dispersion.

How does the RGB color model work?

RGB creates colors by combining red, green and blue light at different intensities. It is an additive model used in screens, where all three at full strength give white.