Interdisciplinary Workshop 4:

​For this workshop, participants will be investigating the various uses of historic dyes and their associated chemical properties. This inquiry-based workshop will engage participants in laboratory experimentation into the various steps of the dyeing process and the use of modern chemical understanding to explain the findings of the laboratory experiments. We will discuss historical and cultural relevance of natural dyes. The workshop will begin by using some historical dyeing processes, an art-form that has been practiced for thousands of years across nearly every culture. Background information will be provided on the chemical and biological significance of each step in order to explain the laboratory results they will observe in the laboratory experience. The laboratory component will consist of experimentation on the major steps found in the dyeing process, starting with extraction and preparation of a dye from the natural source (such as tree bark or a flower petal), combining either the dye (or fabric) with a mordant to aid in the uptake of dye into the fabric/material, (pre/post/non-mordanting), as well as the use of various materials (cotton vs. nylon) and their ability to bond with the dye. A key feature of this inquiry-based laboratory component will be the use of null experiments that allow participants to firsthand observe a non-expected outcome, an important part of any modern scientific process. Lastly, the participants will be asked to reflect upon a set of questions that provide ample follow-up discussion material that link together the historical background with the laboratory experiments. This discussion will include qualitative observations from the laboratory, as well as chemical/biological concepts such as bonding, inter-molecular forces, and kinetics.

Art conservation involves “the application of chemistry to the technical examination, authentication, and preservation of cultural property. Chemists working in museums engage in a broad range of investigations, most frequently studying the chemical composition and structure of artifacts, their corrosion products, and the materials used in their repair, restoration, and conservation. The effects of the museum environment, including air pollutants, fluctuations in temperature and relative humidity, biological activity, and ultraviolet and visible illumination, represent a second major area of research. A third area of interest is the evaluation of the effectiveness, safety, and long-term stability of materials and techniques for the conservation of works of art. Though analytical techniques appear to dominate, many other areas of chemistry, biology, physics, and engineering, including polymer chemistry, kinetic studies, imaging methodologies, biodegradation studies, dating methods, computer modeling, metallography, and corrosion engineering, play active roles in conservation science."  (<https://www.accessscience.com/content/art-conservation-chemistry/052250>)

​Professor Jocelyn Alcántara-García joined the Winterthur Museum Scientific Research and Analysis Laboratory Conservation program in the fall of 2014 after working for about five years in interdisciplinary projects (predominantly in Mexico, where she was born). All projects were conducted in close collaboration with conservators and scientists, and included the examination of iron gall inks, archaeological organic materials and seashells, research on degradation of certain conservation and restoration materials, investigation for the development of novel methodologies for paper stabilization as well as identification of binding media in pre-Columbian wall paintings and non-destructive examination of archival material.

​Dr. Zachary Voras is a Preceptor in the Interdisciplinary Science Learning Laboratories. He earned his Ph.D. in analytical chemistry from the University of Delaware in 2017. He worked closely with colleagues in the Art Conservation program particularly in the use of advanced spectroscopic techniques. He recently published: “Comparison of Oil and Egg Tempera Paint Systems using Time-of- Flight Secondary Ion Mass Spectrometry (ToF-SIMS)” in Studies in Conservation.