SOS Design is a series of articles covering design basics.

Whenever I think of graphic design, the first thing that comes to my mind are colors. This should come as no surprise: colors are one of the main pillars of graphic design, if not the main pillar.

Before delving into color theory, let’s briefly examine the nature of colors and how we perceive them.

First of all, colors are born from light. No light, no colors, easy. Matter of fact, black is not even considered a color!

Every color has a unique property called wavelength, that makes it perceived as such by the human eye. The color with the highest wave length is red, while violet is the color with the lowest wavelength.

Color perception is a process that involves 3 essential elements (fig.1):

• Light: By convention, “light” refers only to the visible part of the spectrum. It is also commonly referred to as pure white light, which is composed of all the visible colors.
• Eye: Light waves stimulate the photoreceptors in the retina, which in turn sends the information to the brain to be interpreted.
• An object: Depending on their chemical/biological composition, objects can emit or absorb light. Objects that absorb light are called Light absorbing objects.

Light absorbing objects

When exposed to light, these objects absorb / reflect light waves of various frequencies (colors). Unless it’s 100% black or white, every object absorbs all the colors except its own, which gets reflected on its surface and lands in the retina. It’s the chemical composition of objects that determines their absorption / reflection attributes. In the figure below, the balloon is red, and thus absorbs all the colors except red.

It is also important to remember that black objects absorb all the colors (Fig.2), while white objects reflect the whole spectrum (Fig.3).

Next comes another important player in color perception: light emitting objects.

Light emitting objects

Also known as light sources, they emit light that can land directly in the eye without bouncing off other objects’ surfaces. Examples include light bulbs, screens and of course the largest light source known to man: the sun*. These objects can emit pure white or hued (colored) light following various mechanisms such as incandescence or fluorescence. Hued light is obtained by filtering out a narrower wave length interval of the light spectrum.

Question

Now what if we expose the red balloon in the first figure to a blue hued light source?

Here is the Answer.

*No need to flame the comments section, I know that there are thousands of stars larger and brighter than the sun…