Thermochromic materials in the paints and varnishes sector. Part I: perception and measurement of color

Considerations about thermochromism should begin with exploring the issue of color. Only the assimilation of the basic laws and phenomena that rule the world of colors, and the resulting classification systems, will allow for a proper understanding of this matter. This article presents the most important information regarding color perception, especially from a mathematical perspective, in a concise and accessible way. Color spaces known and used in the paint and varnish sector are described, including: CIELab, and commercially important color classification systems, such as RAL or Natural Color System. The methods of color measurement along with dedicated equipment and standards that are used in the everyday work of a coatings technology specialist are presented. A brief review of the state of knowledge in the field of chromism and its various types was made.