Dr. Eric Kirchner (Akzo Nobel Car Refinishes)
The Physics behind the Color of your Car

Leiden University - Friday 4 July at 13.15 hrs (13.00 hrs coffee and tea)
De Sitterzaal – Oortbuilding

In the 1920’s Henry Ford could state that any customer could have a car painted any color that he wanted, so long as it is black. Nowadays, about 40.000 different car colors populate the highways. In order to be able to repair each of those colors, pigments need to be mixed until reflection curves match within 0.1% across the visible spectrum. To do so, practical solutions have been developed based on fundamental research. In our research laboratory, we perform psychophysical tests to find out which color differences can be recognized by the human visual system. In particular, during the lecture we will highlight the development of a revolutionary new instrument to measure not only color but also texture. In spite of these successful developments, several unsolved problems remain. Can rheological studies reveal the physical mechanism that makes the asymmetric pigments orient themselves parallel in the coating? How to quantify this orientation with confocal or light microscopy? And what set of illumination/detection geometries is optimum for recognizing interference pigments? And how does texture affect the apparent color difference between two samples? Tentative answers to these questions will be discussed.