Woodblock prints were first produced in Japan during the sixth to eighth century. However, was not until the beginning of the 17th century during the Edo period (1603-1868) that the full potential of woodblock printing as a means to create popular imaginery for mass consumption developed. Early woodblock prints (1650s-1740s) were printed in black line. In 1765 several color blocks could be printed, leading to full color nishiki-e (brocade prints). Non or minimally-invasive analytical techniques are particularly important for the study of woodblock prints, since the dyes are usually present at very thin layers absorbed by paper fibers. For this reason, the use of Surface Enhanced Raman Spectroscopy (SERS) is appropriate for the study of dyes used in woodblock prints. Safflower is a famous traditional natural dye with a brilliant red hue. The main coloring matter is carthamin. Due to the poor light fastness and the high sensitivity to pH and oxygen of the chromophore, the red color rapidly fades in historic textiles. Safflower red has been used since ancient times for dyeing cotton and silk in Southern Asia. Asia. It entered China along the Silk Route and reached Japan in the second century. It was used in Japanese woodblock prints dated earlier than 1869. In this work, the analysis of paper dyed with safflower red was carried out by SERS using different conditions, such as neutral and acidic pH and previous hydrolysis with HF. The red dye was obtained by direct extraction from the petals of Carthamus tinctorius L. The main goal was to determine the best experimental conditions for the detection of safflower red in paper. Two types of papers were used, the regular Whatman paper and Japanese paper. DFT calculations were also carried out in order to assign the experimental SERS bands to the vibrational normal modes of the dye. The B3LYP/6-31G** was employed giving rise to a calculated Raman spectrum that fits well the experimental spectra.

Center for Discovery and Innovation (CDI) at City College of New York, USA. (CCNY). 06 of Decembrer, 2018. --.file:///C:/Users/BIBLIO~1/AppData/Local/Temp/CONGRESOS_Y_CONFERENCIAS745003_VAL.pdf