Published: July 11, 2019
by Erin Nolan
We’ve talked about color before on the blog. Today we thought we’d take a little different look at it. You know how color can help to convey a temperature, a mood, a feeling, etc. But how, exactly, does color work? We’re glad you asked!
How Does It Work?
Color is perceived when an object reflects light at specific wavelengths. Depending on the length of the light wave, specific colors are reflected back to our eye. Other wavelengths are absorbed and do not bounce back, so those light waves and the colors associate with them are not perceived. An object appears white when it reflects all wavelengths and black when it absorbs them all.
Right. Now pretend you are looking at an orange.
Light waves hit the orange, ricocheting into the light-sensitive retina at the back of your eye. That’s where tiny photo receptor cells called cones come in. Cones communicate color information. About 2/3 of them respond to red light, about a third respond to green light, and just a small fraction, about 2%, respond to blue light. Varying degrees of each of these cones share their information with the optic nerve, which then passes a note to the cerebral cortex (let’s call it “Corey”) in your brain. Your brain asks, “What color is this thing I am looking at?”
Corey replies, “Dude! I’ve got it! This is orange!”
Corey is so smart.
Ultra, Infra, and RGB
Varying frequencies activating your cones can create an infinite number of colors. There are even colors that we cannot see with our human eyes (and if you can, we’d love to hear about it). These are ultraviolet and infrared. Ultraviolet waves are further along the spectrum than violet, which has the shortest wavelength. Hence ultra violet. Infrared waves are, you guessed it, longer waves than what we perceive as red, which has the longest wavelength. If our eyes somehow acquired different receptors, imagine all the different waves of lights we could see!
Every perceivable color can be made in a combination of red, green, and blue; therefore, color created by light is called RGB. You might recognize those letters. If you do then kudos to you! Computer monitors, televisions, mobile phone screens, and the world around us is created by RGB light. If you looked at your screen, you will see these three colors. Place a drop of water on your screen to see them more easily (on second thought, don’t—we don’t want to pay for that). Because mixing colors of light together makes additional colors, RGB scale colors are called additive primaries. It just so happens that those are the same colors the cones at the back of your eye are stimulated by. Cool, eh?
Hooray!! We now understand everything about color! The end…said no art student ever.
It’s not that simple. It never is.
What’s Made of Ham and Freshens Your Breath?
There is a second type of color: colors made with pigment. Like RGB colors, pigments can also be made into an infinite number of colors. However, their primary colors are different. They are magenta, yellow, and cyan. When these are used in a printer, it is called CMYK, for the starting letters of each element of the color. The K stands for black. Why? In printing, which uses pigment, black was originally used as the “key block.” That means that all the other colors were placed and printed according to where the black outlines were laid.
When used in fine art, the color primary combination is shown as red, yellow, and blue. Think of paint, for example. If you mixed all the pigment colors together, you would no longer make white. You would create black. White is, with pigments, the absence of all color. It is a completely different way of thinking. It doesn’t matter if they are called CMYK or red, yellow, blue; both groupings are called subtractive primaries. Coincidentally, subtractive primaries are the complimentary of the additive primaries (gasp!). But that’s getting into some big concepts of color which we’ve explored earlier on this blog. Check them out here.
Each of these color blogs is just one tiny spoke of an ice crystal at the tippy-top of an extremely large iceberg of information about color. The more we learn about it, the more we realize there is to know. But we’re big fans of remaining curious and continuing to learn, no matter how much we know, and we hope you are, too.
Continue Learning
If your brain isn’t full after all of this delicious color, check out this sweet infographic about additive and subtractive colors.
And if you haven’t already, check out our two previous entries in this series: Part 1: Line, and Part 2: Shape.