Colour Spectrum

When I was taught about colour, regarding the printing process, I was taught that a printer should be calibrated to produce the colours expected. I was also taught that each person may have a different perception of colour, meaning… what you see as blue, I may see as red… depending upon the receptive colour cones in your eyes. This means that the percentage of ink used in any printing process is absolutely vital in presenting a quality image.

I argue that the colour spectrum is constant… so (for example) if I see a red colour, and you see a blue colour, it really doesn’t matter. Because you were taught to call red blue… while I was taught to call red red. The only consistent thing is the colour spectrum – Red, Orange, Yellow, Green, Blue, Indigo, Violet. No matter what colour you see, the colour differences will be the same for everyone.

If I was looking at a red colour – or what I perceived to be red, I will be looking at light with a certain wavelength. If you perceived that same wavelength as blue (or what I believe is blue), we are still looking at the same light wavelength. So all other colours will change proportionately according to the colour spectrum.

So – according to the known colour spectrum – if you see red & I see blue, it should mean that if I see blue, you should see orange. If that makes sense.


This means that calibrating printers is necessary, but not absolutely essential – if it looks correct to you, it should look correct to everyone. Saying that… there are some ways to get better results using CMYK inks…

CMYK Colours

When it comes to printing, using CMYK inks (Cyan, Magenta, Yellow & Black), some colours are not really achievable – for example, a bright, luminous green or yellow.

Most printing companies are aware that using a mixture of colours is often the best way to achieve a nice strong colour. If you are trying to achieve a rich black colour, it is better to use 100% Black (K) mixed with 40% Cyan… as seen below.

Rich Black


The colour on the left uses 100% Black (K), which when printed can sometimes look a bit weak & faded. Mixing 100% black ink with 40% Cyan (middle colour) produces a rich, metallic black. Mixing 100% black ink with 40% Cyan, 40% Magenta & 40% Yellow (right colour) produces an even richer, warmer black.

Rich Grey


This method can also be used for grey colours. The image above shows 10% Black (K) on the left. Depending upon the printer, some grey colours, or single colours of less than 10% may not be seen when printed, so it is a good idea to mix inks to produce a stronger, yet not darker colour.

The colour in the middle is 10% Black (K) mixed with 5% Cyan, 5% Magenta & 5% Yellow. The colour on the right uses 10% of all CMYK colours, producing a nice warm grey colour.

You can experiment with using slightly more yellow or magenta to produce different, warmer shades of grey… try not to waste too much paper though.

Posted on July 18, 2014 at 6:41 pm


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