This document describes requirements for tooth-like colour representations made of ceramic materials used to determine the tooth colour in the patient s mouth or to check the colour of dental prosthesis, which are referred to as colour tabs in this document. The colour coordinates of colour tabs are left to the manufacturers discretion together with colour shifting of ceramic and other masses or materials used in manufacturing the dental prosthesis. All those do not fall into the scope of this document. Resources for visualizing the colours of ceramic and other masses, e.g. mass shade guides and colour patterns for certain ceramic and other masses, do not fall into the scope of this document. They can be manufactured from any materials and serve solely to illustrate the colour effect; they do not serve to determine colour inside the mouth.