A lot of works have already been done on colour perception (e.g. Berlin and Kay studies ). We have studied the 11 colour reduction scheme. One of the motivation of this work was the need for an appropriate colour characterization of objects in surveillance applications. We seek a colour reduction scheme that is both compact and that matches well the way human memorize and specify colours. Several versions have been built based on different experimentations to gather samples based on human perception. We have compared our performances on images retrieval tasks using an eBay images database. We will also present a colour implementation of the EMD (Earth Mover Distance) and an Image search engine. …