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The Science Behind Hair Color

Is hair color really a science?

Turn on E! News, browse a few articles in Vogue, or scroll down your Instagram feed, and you will find an abundance of hair colors. 

From platinum blonde to midnight black, from mermaid teal to rainbow ombré, we often use hair color as an accessory. When done right and with careful tact, hair color can be our BEST accessory. 

Whether you are a seasoned hair stylist, a cosmetology student, or simply entertaining the idea of attending cosmetology school, understanding the basic science behind hair color is largely beneficial to your career or career prospect. 

In this blog post, we will discuss the following:

  • How light works
      1. Visible light
      2. Reflection and refraction
  • Creating color
    1. The color wheel
      1. Primary colors 
      2. Secondary colors
      3. Tertiary colors
    2. Natural hair color
      1. Tone
    3. Artificial hair color
      1. Using color to enhance
      2. Using color to correct

Let’s talk about hair color!

How Does Light Work?

We wake up to sunlight beaming through the window pane. We take a sunny stroll to the market or leisurely walk our dog on the sunny side of the street. We BBQ on the patio with friends and loved ones as the sun sets to illuminate the other side of the world…

Light is a big part of our lives. 

Rarely do we stop to think about how light works and how it pertains to a career path in cosmetology. The time is now! 

Visible Light

The big, beautiful sun emits a wide range of electromagnetic radiation, also known as “solar energy.” Much of this solar energy we, as humans, cannot actually see. In fact, we can only see a fraction of the sun’s energy in the form of visible light

Visible light is composed of a spectrum of colors with varying wavelengths. The full spectrum of colors are: red, orange, yellow, green, blue, indigo, and violet. Sound familiar? Everybody join in: ROY-G-BIV. Hooray! 

Reflection and Refraction

Light is pretty simple: it travels in a straight line until it hits something (much like us sending a “quick” text while walking on the sidewalk). 

Once light hits an object, it is either reflected or refracted. White light reflects off of an object with pigment; the color we ultimately see from an object with pigment is the reflected color while all other colors are absorbed. A clear object (like a prism or a droplet of water) refracts white light, which means it bends light in a different direction and reveals every color in the visible light spectrum. The result to the human eye is a rainbow. 

Creating Color

Now that we have addressed color in its most natural form, through visible light, we can talk about creating color. And so the fun begins!

One of the most exciting parts about cosmetology is the opportunity to exercise creativity. A major facet of creativity in the world of cosmetology is coloring. You can take “blah” and make it “WOW!” You can enhance natural beauty or find beauty in the unexpected. 

Let’s not get ahead of ourselves. First things, first: the color wheel.

The Color Wheel

Before we delve into color as it pertains to hair, we have to take a look at the color wheel at large. Chances are you have encountered a variation of this diagram at some point in your education:

You have, haven’t you? 

This diagram is called a “color wheel” and was first documented by mathematician Sir Isaac Newton in 1666 as a way to show the relationship between the full spectrum of colors. Though Newton’s color wheel has changed aesthetically over the past 355 years, the concept has largely remained the same. Pretty cool, huh? Thanks, Isaac!

The color wheel is composed of three color categories: primary colors, secondary colors, and tertiary colors.

Primary Colors

Primary colors are unique in that they cannot be made by any combination of colors; they march to the beat of their own drum, if you will. 

There are three primary colors: red, blue, and yellow

Secondary Colors

Secondary colors are the love children of primary colors. There are three secondary colors: violet, green, and orange

Here’s how they were made:

  • Red + Blue = Purple
  • Blue + Yellow = Green
  • Red + Yellow = Orange

Tertiary Colors

Next round of colors on the color wheel are called “tertiary colors.” Tertiary colors are created by combining primary and secondary colors. These colors are generally identified by hyphenating the color combinations, though artists gave them fancy names in true artist fashion.

The tertiary colors are: yellow-orange (amber), red-orange (vermillion), red-purple (magenta), blue purple (violet), blue-green (teal), and yellow-green (chartreuse). 

Natural Hair Color

Natural hair color is what we see when light reflects off of the melanin found in the hair’s cortex. There are two types of melanin found in hair: eumelanin and pheomelanin

Eumelanin is responsible for shades of black and brown and pheomelanin is responsible for red and orange. The level of eumelanin and pheomelanin in the hair is responsible for the varying shades of natural hair color and the resulting warm or cool tones. 


The tone of a person’s hair is either warm or cool. The black or brown colors created by the eumelanin pigment is considered “cool” or “ash”, while the presence of pheomelanin’s red and orange spectrum of color is “warm” or “golden,” “auburn,” and “chestnut.” 

Artificial Hair Color

A broad knowledge of light, the color wheel (including primary colors, secondary colors, and tertiary colors) natural hair pigment, and tone will set a solid foundation from which to refine your coloring expertise. 

There is a massive potential to develop long-term, trusting relationships with clientele who look to you as a color Yoda. 

Picture this: a frantic client walks into the salon desperately seeking a remedy for a bad dye job. You take a look at her current color, you assess her natural color, and you use a color formula based on color theory to create a masterpiece. She is happy, you are happy, and she comes to you for colors and cuts long into the future. Major win!

Using Color to Enhance

Take a look at this color wheel indicating complementary colors:

Complementary colors are colors that exist opposite one another on the color wheel. These pairings include one primary color and one secondary color. For example: red (primary) and green (secondary) are complementary colors. 

Let’s say you have a client eager to find a color that will enhance their beautiful blue eyes. The color wheel tells us that orange is the complementary color of blue. With this knowledge, you can recommend a color with copper tones if complexion permits. Voila! You have striking blue eyes with a brilliant copper mane and one very happy customer.

Using Color to Correct

You can also use the concept of complementary colors to correct or neutralize unwanted tones in your client’s hair color. 

Going back to our example of the frantic client with a disappointing dye job… Let’s say she asked for auburn and ended up with a head of flaming red hair. Yikes! 

Referencing our color wheel, green is red’s complementary color. To neutralize the vibrancy of the red, you need a dab of green. The result: a copper color correction and a happy client.

Does the science of hair color pique your interest?

Despite the large amount of information we covered in this blog post, we only scratched the surface. The science of light, the color wheel, primary, secondary, and tertiary colors, natural hair color, tone, and complimentary colors are just a few of the fascinating topics you will learn on your quest to become a cosmetology professional.

Take your interest a step further and enroll in our cosmetology program at Avenue Five Institute. Our new hybrid cosmetology program allows you the flexibility to pursue your dreams while living your life. With a combination of online learning and hands-on styling in a student salon, you will gain the knowledge you need to pursue a career in cosmetology. 

Stop putting off your dreams and Learn more now.