An overview of methods for matching paint color identifies three different types. A precise description of the respective method is important, particularly for effects with aluminum and interference pigments, since the effect is heavily dependent on the selected measurement geometries. Measurement geometry defines the combination of the illumination angle with that of the detector. This results in a color that is assigned exactly to this geometry. The three methods presented here are: visual matching at the window or in the light cabin; instrument-based measurement with the relevant portable devices; as well as the description of the optical properties.
At the window, the sample plate is held to the light and tilted up and down. The sample plate is also often held upside down, with the subjects standing with their backs to the light source. There are walk-in light booths where the assessment is similar to that at the window. In light booths that have a table or a work space, the test is made while sitting. Here, the sample plate is usually held in the ray path of the light source – usually high up in the cabin – and evaluated.