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The International Colour Chart
The International Colour Chart (ICC) is a numerical system used worldwide to classify hair colour. It means that each hair colour has a definition that is recognised around the globe.
Consequently, this can be used on hair colour charts and tubes or boxes of hair dyes. This creates a level playing field for hairdressers worldwide. Whether or not they choose to use it is another thing.
How It Works
Each hair colour is given a number, which tells us two things:
- The depth (also called level or base) of the colour;
- If there are any tones in the colour.
The depth number is usually separated from the tone number by a dividing symbol like a decimal point, a slash or a hyphen. For example: 4.6, 4/6, 4-6 all say the same thing as far as the ICC go. A 4.6 translates into English as “a medium brown base with a warm red tone”.
However, not all hair colour brands use the ICC and simply use their own in-house numbering system. For instance, letters may be used to represent the different tones, like R for red, or M for mahogany and V for violet.
Even if a brand does use the ICC system, the finished colour can vary from product to product. This means that one brand’s number 4.15 could look slightly different on the hair to another brand’s 4.15.
It’s not a perfect system, but the ICC goes a long way to trying to standard how we define hair colouring products.
How Depth is Numbered
Depth is given a whole number from 1 to 10, where 1 is the darkest hair colour (black) and 10 is the lightest (lightest blonde).
Some brands also use 11 and 12 on their colouring products to account for the blondest of the blonde. As you can see in the picture, numbers 1-5 are browns and 6-10 are blondes.
The depth is also known as “level” or “base colour“. Whatever term you use, it is a neutral colour, neither warm nor cool.
How Tone is Numbered
The tone number comes after the decimal point and each tone is given a number from .1 to .9.
Products can have up to three tones in it, though one and two tones are most commonly seen. This is indicated by how many numbers follow the decimal point. For example, a 4.15 has two tones in it and a 5.016 has three tones in it.
Primary & Secondary Tones
The primary tone is the first number after the decimal point, and the second number is the secondary tone.
The primary tone is more dominate and has more influence over the final colour than a secondary tone. Likewise, any third tone used will be less influential over the final colour than the other two tones used.
The ICC Numbers for Tones
The ICC numbering system for tones is not followed by all hair tint brands. Therefore, it is important to know how that particular brand labels its tones.
|ICC Number||Tone||Actual Colour||Cool or Warm|
|.0||(no tone)||(no tone)||Neutral|
|.x0||–||–||Depends on primary tone
Other Aspects of Tone Numbering
Zero is used to indicate how intense a tone is. For example, a 4.06 is a medium brown with just a hint of red, creating a warm coffee colour. On the other hand, a 4.60 is medium brown with a more definite and obvious red tone to the hair – even more than a 4.6 would have.
Double tone means a greater intensity and vibrancy of that particular tone. For example, a 4.66 means a really vibrant red tone on medium brown hair.
Mahogany (a mix of red and purple) is normally used with another tone in hair colour, rather than just on its own. Mahogany is neutral, meaning is neither warm nor cool. Therefore, the tone that it is paired with determines whether the final hair colour is warm or cool. For example, a 4.15 is a cool colour, whereas a 4.56 would be a warm colour.
Hair Colour Chart Examples
Each brand lays out their hair colour charts for hairdressing differently, though they are generally logical. For example, they are usually organised into columns or rows with the tonal groups (like mahogany, red or ash) kept together.
Below are some examples of hair colour charts to see how they are laid out and how the ICC is used.