The Science Behind Hair Color - Avenue Five Institute (2022)

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!

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.

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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.

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.

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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.

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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.

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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.


What is the science behind hair color? ›

Chemistry: Large molecules of color go between the hair cuticles and cover the hair surface. Chemistry: Small molecules of color enter every hair cuticle and enter the hair's cortex. Chemistry: Small molecules of color enter every hair cuticle and enter the hair's cortex to react with melanin in hair.

What Does RV stand for in hair color? ›

3/RV = Dark Brown Red Violet.

What is a Level 5 hair? ›

Level 1 haircolor is black, level 2 haircolor is the second darkest black, 3 is brown/black, level 4 haircolor is dark brown, level 5 haircolor is light brown, level 6 haircolor is dark blond, level 7 haircolor is dark blond, level 8 haircolor is medium blond, 9 is light blond and 10 is white/platinum.

What does GB mean in hair color? ›

nn= natURal natURal. N@GB= natuRaL GoLD bRown. N@Bp= natuRaL bRown PEaRL. N@BK= natuRaL bRown CoPPER.

Why does hydrogen peroxide lighten hair? ›

Hydrogen peroxide to lighten hair

This is because hydrogen peroxide works in the hair cortex, the innermost part of the hair that holds the pigment that gives hair its color. Hydrogen-peroxide-based dyes alone can help take your hair to a light blonde color.

How can I increase melanin in my hair? ›

Vitamin A, C and B12 are the most needed vitamins to increase the melanin production in your hair. Add citrus fruits like oranges, grapes, pineapple, and melon to your diet. Also eat vegetables like potatoes, carrots, beans, etc. Non vegetarians can try adding red meat, chicken liver, fish, and eggs to their diet.

What is the safest hair dye for thinning hair? ›

Consider Salon Color

She suggests you ask about vegetable-based dyes, cellophanes, and hennas, all of which are gentle options for thinning hair. Also, ask your stylist about products that are ammonia- and peroxide-free. And avoid bleach.

What does 00 mean in hair colour? ›

Count a 0 as no tone.

If the number after the decimal is 0, that means there's no tone at all. This is often counted as a true or neutral hair color, meaning it's neither warm nor cool.

What does M mean in hair color? ›

This hair color chart reads from warmest tone to coolest tone. The letters indicate the underlying tones—for example, Vesuvius Red, the image above with 7NCR, is a “Neutral Copper Red”. C stands for copper, A is ash, R is red, and M is mahogany. Warm tones neutralize cool tones and vice versa.

What does 5G mean in hair color? ›

Shade Guide: 5G is a rich, toffee brown shade with gold tones, which will enhance warmth in your hair. For optimal color results, use on your natural dark blonde to darkest brown hair.

What is Level 7 hair color? ›

Level 7 is a term used for dark blonde hair, but it can also refer to some bright or light auburns/reds. It is common to find Level 7 shades in hair dye. Level 7 hair can be flattering on people whose natural hair color is from Level 4 to Level 10.

What level is grey hair? ›

This is commonly known as the level system. Level One means black and Level Ten means the absence of all pigments as the lightest blonde. Gray hair is also the absence of Melanin. There could be as much as two levels of color difference between two different manufacturer's hair colors of the same hair color.

What is the difference between N and NN in hair color? ›

N or NN (more pigment) series contains all three primary colors: red, yellow and blue. This is needed because grey/white hair contains no pigment and will react more to cooler or warmer formulations/colors.

What does 7NN mean in hair color? ›

7NN Medium Intense Blonde Permanent Creme Hair Color.

What does P stand for in Shades EQ? ›

Redken Colorgels and Shades EQ color theory breakdown. Todays series: P (pearl)SERIES. P= grey base + blue/violet. Grey base= lighter shade of black which is a blue base.

Does apple cider vinegar lighten hair? ›

Apple cider vinegar to lighten hair

For lightening, mix one-part apple cider vinegar with six-part waters and spray across the hair. Let it sit for at least 30 minutes before washing it out. You may have to repeat a few times until you see results.

What does baking soda do to your hair? ›

Baking soda dissolved in water helps to remove any buildup of oils, soaps, and other ingredients in typical hair care products. By stripping away this buildup, baking soda can leave hair squeaky-clean, shiny, and soft.

Will baking soda lighten permanent hair color? ›

Baking Soda Paste

Baking soda can be an effective way to remove permanent hair dye naturally because of its lightening properties. Try mixing baking soda with lemon juice, which is acidic, to create a paste. Then, work the paste through your hair, allow it to sit for five minutes, and rinse thoroughly.

What food is high in melanin? ›

Here are 10 foods that help our natural-born melanin glow even more than it already does!
  • Broccoli. Unsplash. ...
  • Turmeric. Unsplash. ...
  • Eggs. Unsplash. ...
  • Red Peppers. Unsplash. ...
  • Peas. Unsplash. ...
  • Orange Fruits and Veggies. Unsplash. ...
  • Almonds. Unsplash. ...
  • Green Tea. Unsplash.
21 Sept 2019

Why does white hair turn dark again? ›

Sometimes, stress, nutritional deficiencies, and other lifestyle factors can halt melanin production. Once these issues are reversed, melanin may be restored. In most cases though, the age at which you start seeing grays — and the extent of them — are controlled by your genes.

What color makes thin hair look thicker? ›

A colour made up of different shades, created by the tie-dye technique or highlights, makes the hair look thicker. More precisely, it is the contrast between light and dark colours which gives the illusion of thicker hair .

What hair color is best for hiding GREY? ›

Colors like butterscotch, light auburn and golden brown, or ash brown for those with a cool skin tone, are all versatile brunette shades that aren't too dark and are some of the best hair colors to hide gray.

Which hair color is best for GREY hair? ›

Best Hair Color for Gray Hair: 10 Trendy Ideas
  • Light Champagne Blonde All-Over Color. ...
  • Deep Auburn With Strawberry Blonde Balayage. ...
  • Warm Chocolate Brown All-Over Color. ...
  • Medium Auburn Chestnut All-Over Color. ...
  • Gray Blending With Ash Brown Lowlights. ...
  • Espresso and Light Golden Brown Balayage. ...
  • White Platinum All-Over Color.
17 Aug 2022

What colour is number 5? ›

Understanding Hair Colour Charts

1 is black, 5 is light brown, 6 is dark blonde, 7 is blonde and 10 is the lightest blonde.

What does 4.15 mean in hair dye? ›

Therefore, the tone it is paired with determines whether the final hair colour is warm or cool. For example, 4.15 is classed as a cool colour, whereas 4.56 would be a warm colour.

Which is darker 5N or 6N? ›

There are nine distinct colors in the series including 1N (Very black), 2N (Black), 3N (Dark Natural Brown), 4N (Medium Natural Brown), 5N (Light Natural Brown), 6N (Dark Natural Blond), 7N (Medium Natural Blonde), 8N (Light Natural Blond), and 10N (Lightest Natural Blond).

How do I know my hair color level? ›

Your hair's level is determined by how light or dark it is. Within each color family - coppers, blondes, browns, blacks, and grays - there are light, medium, and dark levels. For example, a person can have light blonde hair, medium blonde, or dark blonde.

What color is 2 in hair? ›

#2 hair color is the darkest brown hair that you can find. It looks black from afar, but up close, you can see that it's brown. Most black women have dark brown hair, and the number 2 hair color will often match perfectly.

What Colour is 5G? ›

Naturtint Permanent Hair Colour 5G (Light Golden Chestnut)

What color is Loreal 5G? ›

L'Oreal Paris Age Perfect Permanent Hair Color, 5G Medium Soft Golden Brown, 1 kit.

What is 1N hair color? ›

1N Licorice is our darkest black. The N (Natural) Series provides the most complete grey coverage in a range of colors including blacks, browns and blondes.

What is level 10 hair color? ›

Level 10 + above

This level of hair is a light platinum blonde, with very little blonde/yellow tones if any; however as you get into the white blonde range of this level you can do just about any color in the world! Pastels will turn out best on a level 10 base or lighter, since these shades are quite light.

Can I mix 2 colors of hair dye? ›

Mixing 2 Hair Colours gives you incredible freedom and the ability to dictate your Hair Colours Lightness/Darkness, hue and amount of vibrancy. Mixing Hair Colours gives you the ability to: Create a custom Hair Colour that fits your taste. Achieve that in-between Hair Colour.

How many levels will 30 volume lift? ›

30vol developer is ideal for lifting 3 levels using permanent hair color depending on the texture and natural depth of the hair. It can also be used for grey coverage on more resistant hair types. When used with bleach and foils 30 volume works fast and may incur the risk of over-processing.

What color hair should a 60 year old woman have? ›

Silver, ashy, blond, and platinum are indeed the most popular hair color choices for women over 60.

Is it better to go lighter or darker to cover gray hair? ›

For grey hair coverage, we generally recommend that you aim to color slightly lighter than the natural hair color level of your client.

Is grey hair healthier than dyed hair? ›

Grey hair is healthier than artificially colored hair, easier to manage, and not to mention more affordable (for more tips on how to manage your hair see "Hair's Dirty (Half) Dozen").

What does B mean in hair color? ›

The letter associated with the hair color refers to the base tone used in that particular color. A – Ash. B – Blue. BV- Blue-Violet. C – Cool.

How do you dye stubborn GREY hair? ›

When covering stubborn grays, you should mix your color 1:1 with the Welloxon Perfect Opens in a new tab developer. Just make sure you're using the correct volume, opting for 6% to cover grays or reach one level of lift, 9% for two levels of lift, and 12% for three levels of lift.

How do professionals cover GREY hair? ›

Get a single-process color service at the salon.

To mask grays between salon visits, try covering the gray hairs with easy-to-use products like the Rita Hazan Concealer Touch-Up Spray or Root Concealer Temple + Brow Touch-Up Stick.

What is aa hair color? ›

Ash refers to a Hair Colours pigment, or a Hair Colours character, rather than how Light or Dark the shade is. Ash Hair Colours are Cool shades with predominately Blue pigment and hints of Greens that create a Hair Colour that looks smokey and silvery.

What is 6 N color? ›

6N Natural Dark Blonde Permanent Hair Dye.

What color is 9NN? ›

9NN Very Light Intense Blonde Permanent Creme Hair Color.

Will Shades EQ cover GREY? ›

Shades EQ alone can also work on covering gray roots, since it blends the gray without lifting hair's natural pigment.

Is Shades EQ damaging to hair? ›

It's Ammonia-Free, Aka Super Gentle

However, since Shades EQ is a demi-permanent colour, no ammonia is necessary, meaning the process is very gentle on your hair. If your hair's a little more on the damaged side but you're craving a colour change, Redken Shades EQ might be the best option for you!

What does M stand for in Shades EQ? ›

And now, Redken is introducing an innovative new shade family to help you create some of today's top trending tones, mushroom brown and beige blonde! Introducing NEW Shades EQ Matte, Redken's coolest shades with a black to tan background. With this new shade family, you can create natural results with a kiss of cool.

How does hair color work genetics? ›

Human DNA has millions of on and off switches along networks that control how genes function. Genes responsible for hair color come from both parents. Although the genes passed down from a child's parents determine hair color, variations can result in a child having a different hair color than both parents.

What is the chemical reaction in hair colour? ›

Peroxide is used as the developer or oxidizing agent. The developer removes pre-existing color. Peroxide breaks chemical bonds in the hair, releasing sulfur, which accounts for the characteristic odor of hair coloring products. As the melanin is decolorized, a new permanent color is bonded to the hair cortex.

Why does dark hair absorb light? ›

The actual color depends on the type of melanin present in the hair. Black hair absorbs almost all light that hits it because it has a lot of melanin. Little light is reflected and the hair appears black.

Is dying your hair a chemical or physical change? ›

Answer: Temporary Hair Dye: Physical change because it just lies on the hair shaft. Semi-Permanent: Chemical because it's causing a long-lasting color change. ... Bleach: Chemical change because the hydrogen peroxide is reacting with the melanin (the part of the hair that gives it the color).

Why do blondes darken with age? ›

Hormonal changes aren't limited to puberty. Changes in age, nutrition, temperature, sun exposure and various other factors can cause our bodies to change the amounts or types of hormones we make. The genes for making melanin might turn on or off over a lifetime, causing your hair color to change.

Is hair inherited from mother or father? ›

One popular myth is that hair loss in men is passed down from the mother's side of the family while hair loss in women is passed down from the father's side; however, the truth is that the genes for hair loss and hair loss itself are actually passed down from both sides of the family.

What's the rarest hair color? ›

Red is the rarest hair color, according to Dr. Kaplan, and that's because so few MC1R variants are associated with the shade. “Only three variants are associated with red hair,” she says. “If a person has two of these three variants, they almost certainly have red hair.

What is harmful in hair dye? ›

Lead acetate, another common ingredient, is linked to neurotoxicity. Conventional dyes can contain many other harmful chemicals like DMDM hydantoin, methylisothiazolinone, and fragrance. One study of over 25,000 women found that the use of hair dye was associated with increased breast cancer incidence.

What is the main ingredient in hair dye? ›

Oxidative hair dyes contain the oxidizer hydrogen peroxide and a dye intermediate such as paraphenylene-diamine (PPD), resorcinol, and aminophenol. PPD is an aromatic compound, widely used in almost all hair-coloring formulations, because oxidation of this substance with couplers produces colored reaction products.

Does lemon juice lighten hair? ›

Lemon juice contains citric acid, which is a natural bleaching agent. Citric acid can whiten fabrics, and it's sometimes included in skin care products to help lighten dark spots. It's this ingredient that gradually whitens hair, making it appear lighter in color.

Does salt water lighten hair? ›

Saltwater and chlorine are also culprits for lightening,” Gonzalez says. “They alter the natural keratin in your hair, resulting in lighter shades.” If frolicking in the ocean or a pool every day isn't an option or you don't want to leave it to chance, a salt spray or some lemon juice can help things along.

Why do people in hot places have dark hair? ›

Answer 4: Dark hair absorbs more heat. It also emits more heat, so it will be cooler indoors to be dark-haired and warmer out-doors to be dark-haired. Still, it's better to just wear a hat when spending much time outside.

How long does permanent hair dye last? ›

Ideally, permanent hair colour would stay just as vibrant as it was the day you coloured it, at least until the roots grow. On most heads of hair, that would mean a good 6-8 weeks between touch-ups.

Does melanin affect hair color? ›

Hair color is determined by the amount of a pigment called melanin in hair. An abundance of one type of melanin, called eumelanin, gives people black or brown hair. An abundance of another pigment, called pheomelanin, gives people red hair.

Is pouring milk on oatmeal a physical change? ›

Liquid water and ice (frozen water) are both the same substance, water. *If you fold a piece of paper it is a physical change.
ChangesHighlight to reveal Answer
frying an eggChemical
pouring milk on your oatmealPhysical
burning leavesChemical
making salt water to gargle withPhysical
16 more rows


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