SCAN™ is the name for Crown Paints' colour codification system, in which colours are scientifically measured and assigned a unique 6-digit SCAN™ code:

SCAN™ are presented in a logical, easy to understand format.

The format of SCAN™ code is:
G3 (hue) 10 (lightness) 4H (Saturation)

HUE - the colour.
The colour wheel is divided into 24 segments represented by a letter of the alphabet excluding I and O.  Each of the 24 segments is further broken down and given a numerical value from 0-9.  This provides 240 possible Hues.

Lightness - a measurement of the reflection of light, with 0 being the darkest and 99 being the lightest.
Current DDA (Disability Discrimination Act) legislation suggests differntiation in lightness between significant surfaces and features, to assist navigation.  This can immediately be determined using the middle digits of the SCAN™ code.

Saturation - the richness of the colour.
The less saturated the colour, the duller and greyer it appears.  Saturation increases the further the colour is from the centre of the circle.  SCAN™ will allow a differentiation of 240 levels or in percentage terms less than 0.5%.