Introduction

Our eyes are able to see 350.000 different colors. In order to classify in a simple way all these colors, it is necessary to find an objective chart in which the eye itself – with its defaults or imperfections which may vary from one person to another – is not involved.

There are three different ways of classifying colors:

• A pure visual approach: Chevreul, Munsell, Ostwald color sytems;

• A pure physical approach: RVB, CIE XYZ systems;

• A physical approach, but corrected by psychometric data : CIELAB, CIELUV color systems.