The Surprising Science Behind Colour Codes

Patrick Woodhead
May 2, 2018 · 7 min read
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How does a Coca-Cola label in the Philippines have exactly the same colour as one in Canada?

This may seem like a relatively trivial question in today’s world, but 200 years ago we didn’t even understand what colours really were.

Encoding Colours

A lot of work has gone into defining colours scientifically. As a result, many different formats are available to describe exact colours, each suitable for different use cases.

WEB FORMATS

Let’s begin with the three web formats.

RGB

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RGB colours in Pilcro.

What do we mean by additive?

Every RGB colour is formed by adding a certain amount of each of the three primary RGB colours onto a black background.

Subtractive colour

When light enters the human eye after reflecting off a surface (e.g. a piece of paper, a book or a palette of paints), the colour we see depends on which wavelengths of light are absorbed by the surface and which wavelengths are reflected by the surface into our eye.

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Both the screen and the paper appear yellow

Hex

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Hex

Hexadecimal numbers

Hexadecimal is just another way to represent numbers, just like binary and decimal.

HSL

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HSL
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HSL. Source: Wikipedia

PRINT FORMATS

Now let’s look at the print formats, CMYK and Pantone.

CMYK

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CMYK

How does CMYK subtract from white light?

“Cyan is the complement of red, meaning that the cyan serves as a filter that absorbs red. The amount of cyan applied to a white sheet of paper controls how much of the red in white light will be reflected back from the paper.” -Wikipedia

In the same way, Magenta and Yellow, as the complements of Green and Blue respectively, control the amount of Green and Blue light reflected back from the paper.

Pantone

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Pantone
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Choosing a colour in a Pilcro Artboard

Pilcro

We’re here to share our mission: to help people with…

Thanks to Hugo Woodhead and Xanthe Kueppers

Patrick Woodhead

Written by

Design, Mathematics, Cryptography. Contributing writer for Evening Standard, Hackernoon, The Startup. Head of Concept Engineering @ Everledger. Views my own.

Pilcro

Pilcro

We’re here to share our mission: to help people with technology.

Patrick Woodhead

Written by

Design, Mathematics, Cryptography. Contributing writer for Evening Standard, Hackernoon, The Startup. Head of Concept Engineering @ Everledger. Views my own.

Pilcro

Pilcro

We’re here to share our mission: to help people with technology.

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