Special measurement techniques, sample preparation, and attention to detail are prerequisites for the measurement of high-gloss, deep-black coatings. Many believe that the device they use to measure colorful surfaces on a daily basis can also be applied for black measurements without any issues. However, as reflection values approach zero, as is the case for deep-black surfaces, certain technical aspects mean the colorimetric evaluation cannot be carried out reliably and reproducibly. As many are not aware of this, measurement results are often obtained that suggest excessive blackness values or overly blue undertones.
In our last publication on color measurements in Paint and Coatings Industry Magazine in May of 20221, we focused on sample preparation and correct calibration, which have a significant influence on the measurement result. In this part, we look at another aspect, namely which measurement geometry is best suited for each range of color depths.