HORIBA

Secrets of art revealed: HORIBA’s XGT X-ray microscope meets one of Vincent van Gogh’s Paris Period paintings

Blog post   •   Feb 07, 2019 06:24 UTC

As a leading company in analytical measurement systems, HORIBA provides solutions to a variety of industries, including automotive testing, semiconductor instruments, environment measuring instruments, medical diagnosis and scientific instruments. Thanks to our advanced technology, HORIBA is now able to venture into completely new fields.

One of those fields is art restoration and conservation. This is particularly exciting because recent developments in technology make it now possible for specialists in art restoration and conservation to better understand works of art by uncovering processes that have remained secret for many years. Thanks to HORIBA’s deep analysis, it is possible to understand art-production processes for the purpose of restoration. At HORIBA Analytical Laboratories, we explore new analytical techniques, working in close collaboration with museums, universities and private conservators throughout Japan. Our contribution to the art world is to ensure that works of art will continue to be enjoyed forever.

To learn more about this, we visited Mori Art Conservation Studio and interviewed three specialists to gain insight about how they analyzed one of Vincent van Gogh’s Paris Period paintings, by using HORIBA’s XGT X-ray microscope.

**********

Thank you for giving us the opportunity to talk with you today. Let’s being with Mr. Mori. Please tell us a little about your background and interests.

Mr. Naoyoshi Mori (Head Conservator at Mori Art Conservation): Well, back in school in Belgium, I majored in art restoration, and for the past 20 years, I have been running my own studio. While my primary work is restoring what people “see” when they look at pieces of art, over the years I have become aware of the fact that it is essential to really look beyond what we see and analyze works of art from the perspective of those who produced them, taking into account the techniques and knowledge available to them when they produced their art. Over the years, I have met many people in the art world, from artists to curators and thanks to their insight I have confirmed the importance of “seeing behind” the painting or work of art. What we are doing today, analyzing a work of art by using HORIBA’s XGT, is very much at the core of what I do.

Dr. Kaori Taguchi (Junior Associate Professor at Tokai University): After working in art restoration in Italy, I came back to Japan to conduct research about the ethics of art restoration. Today, I work in the more practical aspects of art restoration, but also look at each work of art with a desire to answer two fundamental questions: how it came to be in its current state, and what can we do to restore it and preserve it from here on.

Ms. Nanako Sato (Curator at the Yoshino Gymnasium): Since graduating in art history, I have been working at the Yoshino Gypsum where my responsibilities include storage, analysis and research of pieces of Western Art. Our collection primarily includes works of French Impressionists from the 19th and 20th centuries. My work specializes on works of art with a relatively short restoration history. Part of my research is to look at the background of paintings, the period when they were painted, what was available then, and how artists may have used the knowledge and techniques available at the time.

   

Can you give me a brief description of the analysis you are conducting, and how you use HORIBA’s instruments to analyze the van Gogh painting?

Dr. Taguchi: Our current project involves the analysis and conservation of four works by van Gogh that are stored in different museums throughout Japan. One of the works has probably no record of restoration at all, which indicates that traces of the original process are still present. This is a most unusual project, quite unique, I must say. The HORIBA’s XGT X-ray microscope allows us to see different stages in the production of the painting, something that we can apply to other paintings for the purpose of observing and establishing patterns that may reveal the way of thinking of the artist.

Thanks to our experiences with HORIBA’s XGT X-ray microscope, we have received calls to conduct similar analyses with other projects here in Japan

Mr. Mori: The fact that more often than not, museums have limited access to these analytical instruments such as the HORIBA’s XGT X-ray microscope give value to the work we are conducting. Analysis for the purpose of restoration is a common practice in many countries. What is not common is to use specific types of advanced technology to “reveal” secrets in the artistic processes employed by artists. Thanks to our access to technology, we may be able to even surprise some experts.

In order to make a project of this magnitude successful, it is important to have multi-lateral collaboration. In our case, we have enlisted a company, a university and a private curator. What makes this type of analysis interesting is not only to know what needs to be done in order to preserve a work of art in ways that respect the technical processes behind the painting, but also to understand other types of processes associated with the artistic meaning of the painting. The painting we are analyzing today is a painting from van Gogh’s Paris Period. This is a time when van Gogh began to experiment at length with a broad use of color. With the optical analysis that the XGT X-ray microscope provides, we hope to understand how van Gogh came to express the use of light during that period and what types of techniques he used to achieve his vision.

   

Can you expand on the collaboration between you and HORIBA? In addition, we would like our readers to know what makes this device suited for analyzing works of art.

Dr. Taguchi: When we first discussed this project at the POLA Museum of Art in Kanagawa Prefecture, I realized that we needed to work with a company that could provide us with the right kind of instruments for analysis. I began asking around what type of specialized instruments were available to conduct these experiments and learned about HORIBA’s XGT optical image analyzers. I felt that it would be a good idea to contact HORIBA and learn more about the XGT system and how it may be used to help us do our work. The initial question we needed to answer was how to unravel processes inherent in the production of works of art. Such processes are rarely made public because artists barely leave records describing how they apply different techniques. This is where HORIBA’s XGT X-ray microscope contribution helps, as it enables us conduct non-destructive analysis that reveals with more accurate techniques employed by artists from other historical periods so that we can do our part in preserving their work.

The images generated by the XGTs element mapping function make it possible to understand which elements are present at different points of production (from right to left: Zinc (Zn), Copper (Cu), Lead (Pb), Mercury (Hg))


What, specifically, can be understood from an analysis of this kind?

Mr. Mori: One aspect of our research involves finding areas where the concentration of pigments is high. The primary reason behind this investigation is to determine whether those particular areas in a painting indicate that they have been painted over. Understanding what happened in those areas helps us determine whether the artist experienced a change of mind during the painting process, or, in some cases, identify sections that were retouched for effect. By understanding the differences between areas with high concentration of pigments, we can gain insight into decisions made by the painter as part of the process of completing the work of art.

Dr. Taguchi: It is important to note that this type of analysis reveals the many layers that compose a work of art. By layers, I mean the different stages that inevitably change as the work progresses. This kind of analysis helps us “see” the original sketches of the work, as well as the final product. Thanks to this type of research, we can determine what has changed due to restoration. In this particular project, we have been able to uncover – quite literally – most of the changes that van Gogh implemented during the painting process. 

   

Are there any other recent examples of such findings that have been obtained through analysis? 

Dr. Taguchi: Yes, there are many surprising discoveries by conducting this kind of research. For example, a recent study revealed that the facial expression of the lamb in The Ghent Altarpiece changed many times during restoration.

Mr. Mori: Another good example is the famed Picasso picture of a Mother and Child at the Beach, which is also exhibited at the POLA Museum in Kanagawa. To everyone’s surprise, a carved seal appeared underneath the mother, something that remained unseen for decades. Discoveries like these reignite scholars’ interest and result in new theories, in this case leading to questions like “why was the seal there? Was it part of a different painting or was Picasso trying to include it as a message?”

   

It goes without saying that these are timeless pieces of art. What measurements do you use to ensure the safety of the paintings during such an analysis?

Mr. Mori: Firstly, we are not only responsible for the process during restoration and analysis; we also give appropriate advice about packing and shipping of the works in question. 

Dr. Taguchi: During the analysis, we work closely with HORIBA’s application engineers to set special climatic conditions to ensure the environmental safety of the work of art. For instance, the XGT usually conducts measurements in a closed system. That means, conducting the experiment by enclosing the object within a case to ensure that no external factors will affect the experiment. However, in this case, it was determined that such process would be risky, so we modified the protocol of the experiment and conducted the analysis with an opened system. Other adjustments were made. Some of these include: slowing the movement speed of the specimen stage of the analyzer, maintaining the maximum distance possible between the X-rays and installing an instant stop mechanism in case an earthquake occurs. 

Mr. Mori: To elaborate on what Ms. Taguchi said, the X-ray distance was 2 mm in the last model. That distance has been increased to 10 mm now. At the same time, it must be said that our work naturally includes risk. Obviously, the safest course of action is simply storing the painting in a secret location, but in my opinion, this is akin to the painting “dying”. Art is a living organism, and our job is to conduct these processes while thinking of the least risky method, all the while knowing that risk is always present.

   

What future plans are there for this work?

Ms. Sato: The job of an art conservator is two-fold: firstly, we preserve art for future generations to enjoy and appreciate, and secondly, we gain understanding of the artworks through analysis technical analysis. I believe this work is not simply 1+1 equaling 2 – it is more like 1+1 equaling 10. This is the kind of value-added contribution I believe we contribute to the world of art. 

Mr. Mori: To elaborate on what Ms. Taguchi said, the X-ray distance was 2 mm in the last model. That distance has been increased to 10 mm now. At the same time, it must be said that our work naturally includes risk. Obviously, the safest course of action is simply storing the painting in a secret location, but in my opinion, this is akin to the painting “dying”. Art is a living organism, and our job is to conduct these processes while thinking of the least risky method, all the while knowing that risk is always present.

   

What future plans are there for this work?

Ms. Sato: The job of an art conservator is two-fold: firstly, we preserve art for future generations to enjoy and appreciate, and secondly, we gain understanding of the artworks through analysis technical analysis. I believe this work is not simply 1+1 equaling 2 – it is more like 1+1 equaling 10. This is the kind of value-added contribution I believe we contribute to the world of art. 

Mr. Mori: In the short-term, we have received permission to undertake a similar project for another van Gogh painting. In the long-term, we want to continue to reap the seeds we have sown, increasing the frequency of conducting similar projects within Japan through collaboration with universities, museums and companies.

Dr. Taguchi: We want to increase awareness of works of art housed in Japan. Our goal is to continue to show what makes these works so appealing, not only in Japan but overseas as well. We are continuing discussions with researchers from overseas and trying to make our work known to art communities in Europe and the US.

Thank you so much for taking the time to talk with us. 


**********

The field of art preservation and analysis is expanding thanks to developments in technology. Now, we can literally “see” works of art in a new light. Following the interview, we received an update on the results of the analysis. One fact that was revealed is the exact composition of the pigments used by the artist. In this example, three specific areas were closely investigated (see picture). On the top right, it was determined that van Gogh used chrome yellow coloring to highlight details of the flower. There are traces of white lead found in the white areas of the vase, indicating that van Gogh was experimenting with lead as a way to highlight that color. At the bottom left area, where van Gogh signed the work a vermillion-based pigment was found, suggesting the use of mercury. This kind of precise analysis is just one of the things that can help us understand what experiments were included in the creation process behind the painting.