At ICI Paints, we have developed a unique proprietary colour notation system, one that is the result of extensive research and consultation with an international team of experts.
The role of our notation system is to make every colour we produce precisely identifiable. Each has its own unique reference number made up of three distinct parts: a hue reference, a light reflectance value ( LRV) and a chroma value.
It is this aspect of colour that we see in a rainbow. Most colours have a clear hue associated with them – for example, pink has a red hue. The only colours that have no hue are white, black and the pure greys that lie in between.
The first part of an ICI Paints colour notation describes this aspect of colour by using two digits and two letters, as shown in this diagram.
In order to give a more precise indication, a scale from 00 to 99 is used to locate specific hues within each colour group. For example, 50YY is a pure yellow and is found in the middle of YY; 90GY is more green than 10GY.
This, the second part of the notation system, is a two-digit number of between 00 and 99 and is used to describe how dark or light a colour is (it is actually a measure of how much light is reflected by a surface of that colour).
LRV works on a black to white basis – the higher the LRV, the lighter the colour.
The remaining component of colour is chroma and this measured using three digits, from 000 to 999. It is the chroma that makes a colour either intense or subtle; the higher the number, the more intense the colour will be.