A preliminary study on the photo-degradation of printing pigments on banknotes issued during the period of the Republic of China

In order to do a preliminarily evaluation of the influences of light on banknotes issued during the period of the Republic of China and to provide suggestions for their exhibition and preservation in museums, eight banknotes were selected for light aging tests with LED light and natural light. The main pigments of the banknotes were determined using Raman spectrometry and X-ray fluorescence spectrometry. The results indicate that PR49:1, Prussian blue, lead chromate and carbon black were used. The red pigment (PR49:1) on banknotes faded fastest, while the other pigments had relatively smaller color changes. Therefore, it is necessary to control lighting to prevent the photo-degradation of banknotes, especially those containing synthetic organic red pigments.