J Leonard Dixon

The next day Ren returned from an early meeting on academics and decided to lie down on the office couch for a nap. He was asleep in moments. After a couple of hours he awoke and realized that most of Ali’s samples were probably finished. The nap had cleared Ren’s brain and he jumped off the couch and walked down to the LC/MS lab and started to go through the spectra from Ali’s painting. It was still too early to come to a definitive conclusion, but Ren had an immediate gut feeling about the results. In fact, they were fairly consistent with what he had previously observed at 3 am. The results were leaning toward this- the painting did not contain a significant percentage of any modern components in it, such as acrylic acid, that are the basis of modern paint. This was strong evidence that the painting was indeed old- possibly painted by Van Gogh in the late 1800’s. What the hell was wrong with Ali? He must have picked up some spurious information and freaked out. Ali needed to be pressed for more background about the painting and his concerns. Here was a turn of events- Ren needed to find out the full story behind the Van Gogh. He needed to interrogate his friend, an accomplished trial lawyer. As an experienced scientist, Ren knew that it was important to wait until all the results were in and that it was best to mull over the results before leaping to a final conclusion. There were still some runs to go. It was late in the afternoon and Ren was wiped out from the last few days. He was going to go home early for a change and get some needed sleep.

The next morning Ren was anxious to see what Ali’s Garden and Terrace was made of. He went back into the lab at 6 am. It was Saturday morning so the campus and the building were quiet. Every sample had run. It was time to sift through the immense amount of data that had been collected by the instruments. First Ren brewed a pot of coffee. This was going to take some time. He went to the computer and pulled up the queue of runs. He went to the mid layer of each location in the painting that was sampled and pulled up the highest 10 compounds in each sample. He captured the spectra from the middle of each peak and sent them into the Profiler program, which compares unknown spectra with the library of spectra available on line at the National Bureau of Standards website. Within about 10 minutes, Ren had several matches for each mid layer sample of the painting. The data were strong and convincing. The main compounds picked up were constituents of linseed oil, a major oil base used by artists in the 1800s. Linseed oil (also known as flaxseed oil), is an highly unsaturated oil, meaning each fatty acid contains multiple double bonds. This is a moderately slow drying oil that slowly hardens as the unsaturated double bonds are subjected to oxidation by the air. Therefore, the paint can be worked for a longer time because it hardens much more slowly than paint made from other oils. But when it dries it creates a strong matrix because the oxidation of the double bonds results in multiple cross-links.

At that precise moment Ren noticed another interesting “peak” in the paint. The identity given to it by the National Bureau of Standards blew Ren’s mind. It was myricyl palmitate. Ren went to the internet and keyed in “myricyl palmitate” and after a little reading he understood what it was. Myricyl palmitate was a major component of Bee’s wax. Wax was used as a thickening agent in paint. Adding wax would allow more paint to be applied to the canvas without the paint spreading out and running on the canvas. Ren was sure it was bees wax because myricyl palmitate was the major lipid in beeswax. So it appeared that Van Gogh added about five percent beeswax to his paint. In addition to linseed oil and beeswax, there were a series of smaller compounds that were also derived from plants. These were comprised of a mixture of terpenoids, some oil like compounds, and aromatics. Some of these compounds were commonly used in cosmetics. The compounds the mass spectrometer picked up were limonene, menthol, neral, geranial, phytol, beta-phellandrene (best known from eucalyptus), benzyl alcohol, benzene acetaldehyde, eucalyptol, benzaldehyde (almond smell), beta-carotene, and about a dozen more that were in low quantity. This group of compounds, in the ratios observed in the samples from Garden and Terrace, immediately reminded Ren of an essential oil, a mixture of aromatic and volatile substances extracted using hot water distillation from fragrant plants such as eucalyptus. When Ren put the list from the Van Gogh paint into the database, the essential oil that was closest in composition was lilac oil. Wow, Ren thought, Van Gogh must have mixed lilac oil into his paint. He had no idea why Van Gogh would have done this. Maybe since he liked to paint all sorts of flowers, Van Gogh may have tried to give his paint a floral aroma that would enhance his painting of flowers on the canvas. This was wild conjecture, of course. It occurred to Ren that he essentially knew nothing about this, about Van Gogh, or about painting in general. He had no idea how artists concocted their paints.

The other compounds in the paint were pigments or components of pigments, most of which were classic colors used in the mid to late 1800s. Nothing else came up suspicious with this fast first pass through the spectra from the samples. Ren then looked at the lower layers of paint that were sampled. In many respects the components of the lower layers were similar to what was observed in the mid layers. The main components again were linseed oil with lilac oil and beeswax mixed in. However the main color was predominantly white material, probably containing lead sulfate (PbSO4). No doubt the lower layer was primarily made up of a base foundation of white to cover the canvas. Ren then looked at the upper layers and was swayed that the results were not that much different. This meant that the painting had not been covered with a protective coat in the last 50 years or so. Most importantly, there were no signs of a major modern chemical in any of the layers. Ren smiled. Very seldom do chemical analyses provide definitive results like these after essentially a day’s work. But the power of these modern mass spectrometers were extraordinary. Later on Ren would have Liz look at the top 25 compounds in each sample to get a more thorough list of the components in the paint. But right here, he was convinced that the paint used for Garden and Terrace was authentic 19th century paint. Of course, he would need to mull it over before coming to a final conclusion. Ren did not know what to think about the surprise ingredients, bee’s wax and lilac oil, they found in the paint. But these were natural components, and so in general, it seemed that Ali’s painting was authentic, or at least, it had been painted a long time ago. Ren felt a little dizzy right then. This was an exciting and straight-forward finding. If true, Ren and Liz may have indeed handled several slivers of paint applied by Vincent himself. How cool was that? Ren hoped Van Gogh would forgive his indiscretions.

Liz walked in at 9 am. Ren was amazed to see her in on a Saturday morning. She normally tended her garden on Saturdays. Ren showed Liz what he had done. He asked her to perform a more thorough search through the spectra. She got right to it. Ren was too excited to watch. He did not want to look over her shoulder and make her nervous. He decided to go to his office and look through some journals. At lunchtime he walked over to the pool to swim in order to settle his nerves. Jumping into cold water was always a good way to calm down and get some exercise at the same time.

When Ren walked out of the recreation center he felt calmer and even had a bounce to his step. When he arrived back at the lab he went right to the mass spectrometer rooms to find Liz. She had finished looking at the samples and was getting ready to leave for the day.

Ren asked, “What do you think?”

“I did not find anything that would go against your initial observations. The upper level does have small amounts of modern contamination that evidently comes from cleaning solutions. But there was nothing in the mid to lower layers that would raise a red flag.”

“Hey, that’s great! I’m going to call Ali right now. He is probably at work even though it is Saturday. I’ll call him there. I wonder how he is going to take it?”

He went down the hall to his office and dialed Ali. “Hello Ali, this is Ren. I have some results for you.”

Ali responded after a moment where he seemed startled, “OK, Ren. Give it to me straight. I’m sitting down.”

“Ali, we have some solid data from the tests. Of course, we will need to check the results. This is our major observation: There is nothing in the samples that would lead me to conclude that a modern paint was used in Garden and Terrace. It looks like all the components in the middle to lower layers are natural products that one would expect in authentic 19th century oil paint.

Ali became louder and more excited, “Hey Ren; that’s great. That’s an important step to soothing my fears about my painting. Thanks for doing this for me. I want to come over as soon as possibleand look at the results myself. Even if I don’t know what I am looking at, I want to see the spectra that you always talk about.”

“There were two interesting ingredients in the paint. One, it contains 5 % beeswax, the main component of which is myricyl palmitate. Two, there is also lilac oil in the paint.”

Ali sounded concerned, “Are they problems?”

“I’m not sure. Some artists included beeswax in paint in the late 1800s. It may have aided Van Gogh to use more intense strokes and helped create waves of color. I’m not sure what the inclusion of lilac oil means, or whether it says anything concerning authenticity. I’ll need to go to the library to check this out. Let’s keep these findings in the back of our minds. I am a little worried that they are there in such high amounts. But both of these are natural ingredients, and they were no doubt available when Van Gogh painted in the late 1800s.”

Ali said, “Interesting. I’ll let you think about the results for a few more days. As I said, I want to see them myself, even though I may not know what the hell I am looking at.”

Ren continued, “Do you think you can put your fears concerning the authenticity to rest?”

Ali replied, “I’ll have to see. I need to evaluate what I was told by my source. I’m still worried. The more I hear about Sarkov, the more I think he lives on the dark side.”

Ren responded, “Ali, lets get together real soon. I am happy we obtained reasonable information about the paint. It is always difficult to give bad results to my customers! They often blame me for the bad news! In this case the results look promising.” They hung up and Ren went back into the lab to tidy up.