| AVS 65th International Symposium & Exhibition | |
| Applied Surface Science Division | Thursday Sessions |
| Session AS+SE-ThM |
| Session: | Applied Surface Analysis of Novel, Complex or Challenging Materials |
| Presenter: | Amy Walker, University of Texas at Dallas |
| Authors: | J.K. Hedlund, University of Texas at Dallas L.D. Gelb, University of Texas at Dallas A.V. Walker, University of Texas at Dallas |
| Correspondent: | Click to Email |
José Posada was a Mexican artist active during the turn of the 20th century, and is often called the father of modern Mexican printmaking. Many of his prints (“broadsides”) have vivid colors but are in urgent need of repair. The dyes that give these broadsides their colors are aniline dyes which are soluble in many solvents. Solvents are often used in paper conservation for the removal of pressure-sensitive tapes, and so treatment protocols that preserve these colors are needed. To develop these methods the aniline dyes need to be identified and characterized.
Dye identification requires either non-destructive in situ techniques, such as Raman spectroscopy, or ex situ techniques with very high sensitivity; only extremely small samples can be taken in order to preserve the integrity and appearance of the broadsides. Although Raman spectroscopy has been employed to analyze Posada prints it has only limited success especially in the analysis of blue and yellow dyestuffs.
We present a new strategy for analyzing dyed paper samples using secondary ion mass spectrometry (SIMS) and analysis of the resulting data using maximum a posteriori (MAP) reconstruction. To test our protocol, we first characterized modern cotton paper colored with a range of aniline dyes. Subsequently we analyzed fiber samples taken from Posada prints. Using SIMS, we are able to identify the dyes used in Posada prints, including hitherto unidentified blue and yellow dyes. Furthermore, MAP analysis provides not only unambiguous identification of the dye adsorbed in the paper by comparison with pure-dye reference samples, but also the characteristic mass spectrum of the paper itself.