Color Perception Part 1: The Effect of Light

Posted July 19, 2018 by Shoshana Burgett

When it comes to the way we see color, our eyes can be deceived. This is partially caused by our humble brain, which is managing vast amount of information and processing it the best it can. It can also be related to genetics and the environment; we all see color a little differently. But above all, LIGHT has biggest impact on the colors we see. 

Without getting too technical, here is an introduction to the way light affects our perception of color.

RGB Color Circle

RGB Color Circle

The temperature of light

The visible color spectrum, what we know as the rainbow (RGBIV), encompasses light wavelengths from approximately 380 to 720 nanometers and breaks down into three primary colors: red, green, and blue. We can mix these three colors in various combinations to create millions of beautiful colors. When we mix them in equal quantities, we perceive the color as white. 

 

This is the foundation of the additive – RGB – color model, and the basis for human color vision.

White is not a lack of color

As strange as it sounds, objects themselves don’t have color. They have properties that determine which wavelengths of light are absorbed, and which are reflected. It is the mixture of the reflected light that enters our eyes and gives us the perception of color.

Think about a red car sitting under a streetlight. All of the colors from the halogen light are shining on it, yet we only see red. That’s because the car’s paint is absorbing the green and blue rays of the white light and reflecting the red. When you look at the car, your retina receives the reflected red light and sends a message to the brain: This car is red.

However the shade will change as the color temperature of the sunlight changes. This quick video demonstrates it well.

 

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While the car definitely looks red under noon daylight, it appears bluer under the night sky, and more yellow under fluorescent and horizon sunlight. However, without a point of reference, they all just look red.

 Color Temperatures in Kelvin

Color Temperatures in Kelvin

Color memory can actually make you feel like you’re losing your mind!

Our brains have “learned” how objects should look, and we apply this knowledge to everything we see.

Take white, for example. Magazine pages, newspapers, and printer paper are all white, but if you lay them together, you’ll see that the each white is actually quite different. The newsprint will appear more yellow, and next to the newspaper the printer paper will probably look even brighter than you originally thought. That’s because our eyes tend to capture the brightest part of the scene, call it white, and judge all other colors relative to this “bright-level.”

Here’s a cool optical illusion from Beau Lotto that illustrates how our color memory can completely change the appearance of a color.

Beau Lotto Cube Illusion color perception

Optical Illusion images courtesy of R. Beau Lotto

The center squares on the top and front side of the cube look pretty different – orange on the front, brown on the top, right? But when you mask the rest of the squares, you can see the two are actually identical. That’s because our brain subconsciously factors in the light source and mentally corrects the color on the front of the cube as shadowed. Amazing isn’t it?

Without a point of reference, we each perceive color in our own way. Different people pick up on different visual cues, which changes how we interpret and perceive colors. This is really important to understand in industries where accurate color is crucial. 

Up next…

Continue reading our Color Perception series to learn how the environment and human traits also affect the way we see color, and the impact color perception can have on printing, manufacturing, and photography.

Color Perception Blog Series

Part 1: The Effect of Light
Part 2: The Impact on Manufacturing
Part 3: The Tricks the Environment Plays on Our Eyes
Part 4: Human Traits

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