Introduction to colour specification:
why use a colour system?
Anyone with normal colour vision can see about 10 million colours. Which is why we need a colour system that allows us to describe any colour we can see, that enables us to pinpoint colour precisely and communicate it accurately.
Six elementary colours
Leonardo da Vinci was the first to identify the six elementary colours we see which are: Yellow, Red, Blue, Green, White and Black, and correspond with the perception of colour in our brain.
Then in the late 19C these six colours were shown to correspond with how we actually see colour by the German physiologist Ewald Hering. This simple diagram shows the receptors in our eyes, which correspond to the six elementary colours. It's called the opponent colour theory and it's what NCS is based upon.
Over history there have been many different colour theories based on these dimensional models of colour space. NCS traces its history to the scientist Forsius who published this theory called Physica in 1611. Like Leonardo, Forsius identified the six basic colours of yellow, red, blue, green, white and black.
NCS colour space
This three dimensional model is made up of an axis of White to Black, then Yellow, Red, Blue and Green are placed at the compass points to allow all imaginable surface colours to be plotted and given an NCS notation.
NCS colour circle
By taking a horizontal section through the centre of the model, we find the colour circle, where the space between the four chromatic colours is divided into 10 equal steps. These represent the pages in the NCS Atlas and show the colour hues. The hue Y90R has been highlighted.
NCS colour triangle
The NCS triangle is a vertical section through the NCS model at one of the 10 steps. This is the Y90R section, which shows all the colours on the Atlas page for the hue Y90R between White, Black and the full chromatic colour ('C'). The notation S 1050-Y90R has been highlighted.
How NCS notations work
NCS colour notations are based on how much a given colour seems to resemble these six elementary colours. In the NCS Notation S 1050-Y90R for example, 1050 describes the nuance, ie the degree of resemblance to black, which is 10% and to the maximum chromaticness which is 50%.
The hue Y90R describes the degree of resemblance between yellow and red (Y and R). Y90R describes a yellow with 90% redness and 10% yellowness.
Pure grey colours have no hue and no chromaticness and have a nuance followed by 'N' to describe Neutral. There is a scale from S 0300-N which is white, to S 9000-N which is black. We also have a range of very slightly tinted greys with 2% chromaticness.
When the NCS System is familiar it is possible to judge the appearance of a colour by its notation: for example how much blackness, how much chromaticness, and what hue. This can help when talking about colours or checking specifications.
Can you work out the notation for this colour?
It's a fairly clean and strong blue. How much blackness do you think it has - and how much chromaticness? Try to work it out. Is it a red/blue or a green/blue? Where would it be on the colour circle?
NCS is a user friendly colour language and is the only colour system that describes colour exactly as we see it.
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NCS – Natural Colour System®© property of NCS Colour AB, Stockholm. References to NCS®© are used with permission from NCS Colour AB.