Understanding Colour: Print vs Digital

Printed Colour

Four Colour Printing or CMYK refers to the basic primary inks that are combined to create an entire spectrum of printed colour, they are:

Cyan (C) – a light bright blue colour
Magenta (M) – a bright intense pink colour
Yellow (Y) – a bright primary yellow colour
BlacK (K) – a flat black that is used for tone and shadow

CMYK printing is capable of reproducing a multitude of colours made of various combinations of these four basic inks. For example, to get purple using CMYK you would mix cyan and magenta inks however the percentage of each will change depending on the specific shade of purple you wish to create and may even use a bit of the other inks like yellow or black to get the right tone. All colour brochures, catalogues, magazines, posters, coffee table books, etc. are printed using this method.

The printing process is subtractive in that you subtract colours to get to white eg the less colours you use the closer to white you get. The absence of any colour leaves only white. Alternatively, if you add 100% of all the ink colours together then the colour you produce will be black.

Digital Colours

On the other hand, when you view colours on your computer screen or TV, the images you see are created by light projection. Thousands of colours can be produced from the three digital primary colours:

Red (R) –  a neutral primary red colour
Green (G) – an intense acid green colour
Blue (B) – a deep electric blue colour

The RGB colour model is additive meaning that if you add 100% of all three colours together the result will be white. The absence of all three colours will give you black.

Spot Colours

Pantone Matching System (PMS), more commonly referred to as spot colours, refers to a colour or ink that has been specifically mixed and calibrated to a colour matching system such as Pantone. It is a similar process to picking out paint swatches – a colour is picked from a swatch book and is reproduced exactly in that shade for your document.

Spot colours are typically used in offset printing and screen-printing, usually in large runs. For each spot colour you use, a specific plate has to be made for each which can increase the costs for such a printing job dramatically.

RBG vs CMYK

How does this impact you?

CMYK and RGB colour spaces are on different spectrums due to the fact that one is subtractive and the other additive respectively so this means that they are not compatible in some ways. A colour that you see on screen will never print exactly the same on paper due to these differences although a lot of effort is made by both programmers and printing houses.

This means that when your design work is prepared for printing, your designer should always ensure that they convert any RGB elements to CMYK or, alternatively, if colour accuracy is essential for a particular asset such as a company logo, spot colours are recommended (though it can impact your budget to do so).

Katerina Przita
katerina@easternbloc.com.au

Kat specialises in branding, corporate identity and web design with a special love for illustration and infographic design.

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