Color is one of the most expressive and exciting elements of art. If you want to be a great designer, you have to master color in all of its emotional power and subtle meaning. To do this, it helps to know a little about what color is, how we see it, and how different color combinations can work together to make great art.

If photons vibrate at just the right frequency, they become visible to the human eye. You can see the spectrum of visible light as a rainbow in the middle of this graphic.

Color comes from light. But what is light? Light is really just packets of energy, called photons, traveling at super-fast speeds along different wavelengths. Some of these photons vibrate in short, energetic wavelengths (like UV light and X-Rays), while others go in longer, low energy patterns (like the radio waves used in microwaves and cell phones). Somewhere in the middle are some very special photons that oscillate at just the right frequency for us to see. These unique frequencies make up the visible spectrum.

When a ray of white light passes through a glass prism, the ray is bent, or refracted. It is separated into bands of color, called the color spectrum. You can see the spectrum in a rainbow. Visible light is made of seven wavelength groups. These are the colors you see in a rainbow: red, orange, yellow, green, blue, indigo, and violet—the Mr. ROY G. BIV you might have been introduced to in elementary school. The reddish colors are the long wavelengths. The greenish colors are the mid-size wavelengths, and the bluish colors are the short wavelengths.

When light hits objects, some of the wavelengths are absorbed, and some are reflected back into our eyes. The reflected wavelengths are what we perceive as the object’s color. A black object absorbs almost all of the photons and appears dark, while a white object reflects back almost all of them, and appears bright.

This material, known as Vantablack, is the darkest substance in the world. It absorbs 99.9% of photons and appears completely black.

The mirrors at this solar power facility in California reflect back so much light they can create enough energy for thousands of homes.