We at asma try to improve our products and technologies every day and focus on new innovations. New standards are set in material development of our polyurethane elastomers, but also in the color precision of our products. In view of the highly subjective perception and sensation of a color tone, an objective measurement solution was chosen that enables a process-related verification of the coloration independent of environmental influences (lighting conditions, premises, etc.).
Such measurements are possible with a spectral photometer. The instrument acquires the color spectrum by illuminating (standard light) the sample and analyzing the reflected light. The resulting spectrum is compared with that of a known (white) surface and the spectral properties of the measured surface are calculated from it.
The calculated data are then displayed in a so-called L*a*b* color space (CIELAB) – which evaluates the existing color plane in three dimensions.
This essentially involves 3 axes (see CIELAB sphere):
– Brightness axis L* (white-black / light-dark)
– Green-red axis a*
– Yellow-blue axis b*
Using this data, color characteristics from different batches can be compared objectively over the long term, so that any changes can also be proven by measurement. So it is possible to prove the color change in form of a darkening effect after outdoor weathering with measurement data. In order to be able to coordinate the optimum system with our color suppliers, we can compare different color pigments with each other.
For some of our customers, color fidelity and consistency across the entire product is a major quality priority, which we can ensure and report appropriately using this measurement method.
A report of Thomas Bauernfried – asma quality management