Good morning. Thank you all. Jennifer and I actually have a very long, laundry list and Academy Awards list of thank yous, but we will save those for the end. But I do want to thank everybody who's here this morning in the auditorium and also everybody who's watching live stream for making that crazy decision to come inside today on this beautiful fall day. So as you've heard from Kate and Claudine and Eva Land, part of the initial phase of the project, the catalog project, was to take down every painting in the collection on Framewood and look at it together as a team, which was an incredibly rewarding experience for all of us. One of those included, of course, the joy of life. And it is a pleasure for Jennifer and me to share the research on Le Bonheur de Vieve that started 10 years ago. As many of you remember, Le Bonheur de Vieve was hung in the stairwell in Marion. And taking it down was truly an event. It was in November of 2006. We scheduled scaffolding to be set up so that the painting could be de-installed and photographed for the catalog. And we also organized a team of conservators and scholars to examine the painting while it was down. Jennifer Mass joined us that day to do a survey of the painting with a portable x-ray fluorescence spectrometer, that ray gun that Kate mentioned yesterday. We were most interested in studying the yellow paint at the lower center, which was ultimately found to be a cadmium yellow. For you artists in the audience, not to worry, cadmium yellow is now known to be a stable pigment. But it was, as Jennifer will share further, in some instances at the beginning of the 20th century during its early manufacture, found to be an unstable pigment. That day ultimately took us on a journey that included studying sketches for Le Bonheur de Vieve in Copenhagen and San Francisco. And Jennifer assembled a team of international scientists to study the degradation mechanism of this cadmium yellow. We even made a side trip to Oslo at one point to study a version of Munch's cream, which has a similar issue with the degradation of the yellow. In addition to contributing to our understanding of the materials used by Henri Matisse for our painting, Jennifer's research has contributed to the broader study of the degradation of cadmium yellow in early 20th century painting. Which has important implications for our preservation of these paintings. Jennifer. Thank you so much Barbara. And I'd also like to express my deep appreciation for Sylvie and Alia. We are so delighted to be here today. Okay, I'd like very much to emphasize materials today. We're going to get really deep into the study of the materials used in the four different versions of Le Bonheur de Vieve. And try to understand how these materials are holding up 100 years after these works were made. But first I wanted to take a step back and consider this strange process that we do, the scientific analysis of painting. And we have Anya Shutab here from the Conservation Laboratory and the Barnes Foundation demonstrating X-ray fluorescence, one of the techniques that we used in our study. Am I getting too much feedback? Okay, let's see. Is that better? Excellent, okay thanks. Okay, so one of the things that we do is we look at authenticity. And so we use scientific analysis to try and demonstrate that an object actually is what it purports to be. Another thing that we do when we do the scientific study of paintings is we identify previous restorations. It's estimated that as you walk through a museum, about 20% of what you see is the hand of the restorer and the conservator, and only about 80% is the hand of the artist. But this work has been documented only in about the last 40 years or so, whereas the restoration of objects of art has gone on ever since objects of art have been made. And then also technology of manufacture or what we call today technical art history, we look at the materials of artists and how those materials are used to make images. And that can really profoundly impact our study of the preservation of these works, how these works are changing over time. And that leads to number four, degradation mechanisms. I put a little star there because I think the most important scientific reason to study a painting is to understand how that painting is reacting with its environment so that we know what to do in order to preserve the work for future generations. But there's a big caveat here with these types of studies. And that's the ethical considerations. The code of ethics of the American Institute for Conservation challenges us to do our work either totally non-destructively without taking a sample at all or minimally destructively. And so if we do take a sample, it's on the order of a milligram to a microgram. And so I think about the size of a period at the end of a Times New Roman 10 point sentence. And that's the largest sample we're ever gonna take from an object of art. And a microgram is a thousand times smaller than that. So you should never be able to look at a painting that's been sampled by a conservator or a conservation scientist and see any visual evidence of that sampling. So before I wanna go into paint degradation and explain how paint changes over time, I think it's important for us all to be on the same page in terms of what paint actually is. And you're probably thinking, this is ridiculous, we all know what paint is. But in fact, I was kinda surprised when I got into art conservation, it was a little bit different than I thought it was. So it has three main components, the pigment and the binder and the inert filler. And what we're gonna find out is that the paint manufacturers were not interested in the needs of the artists. They were interested in maximizing their profits. And so the majority of paints are actually made of inert filler, things like chalk and talc and gypsum. And what we're really interested though is the pigment, the precious and expensive, highly colored mineral or manmade compound that's going to give the artist the hue that they desire. And so I'm showing ultramarine and Prussian blue here. And you can see how black Prussian blue is compared to the pure bright blue of ultramarine. If we look now at the binder, in the turn of the 20th century, for oil paint, it's really gonna be linseed oil and poppy seed oil as the main possibilities. If we're talking about watercolor, those are gum based, typically things like gum Arabic and cherry gum. Okay, so we have a saying in English that it's so boring, it's like watching paint dry. Well, I think watching paint dry is fascinating. Every day. I wake up and I'm so excited to do my job and to learn more about how paint dries. And then I even go one step further and I look at what happens after paint dries when nothing is supposed to be happening at all. And we're gonna see that there's a tremendous amount of chemistry that goes on after the paint is quote unquote dry. So first starting with the drying process. Paint is, if we're talking about an oil paint which we are in the case of Le Bonheur de Vives, then it's a triglyceride. It's made up of long chain fatty acids. And the drying process basically involves the fatty acids reacting with oxygen and polymerizing to form a solid film. So this is the process of paint drying. And at your next cocktail party, you can try that out on all your friends and see how excited they are to learn how paint dries. The problem though is even after the paint is dry, these binders continue to react with water just with relative humidity in the environment and undergo hydrolysis. And this frees the fatty acids and causes them to rise to the surface and causes something called fatty acid bloom. And I don't know if any of you have had this experience. I have this experience a lot because I eat a lot of chocolate. But if you open a chocolate bar in the summer, you can see a whitish haze on the surface of the chocolate. That's the fatty acids in the chocolate coming to the surface and blooming. And just the same thing happens on oil paints. So that's one of the things that can happen. But, and that's pretty easy from a conservation perspective to take care of. Pigments though are another story. It's just, it's a nightmare. I mean they react with water, visible light, ultraviolet light, sulfur dioxide, carbon dioxide, oxygen, and they even react with each other. And so there's so much chemically going on in a painting that can change the work from the artist's original intent. And the way that we study some of these mechanisms is to take that tiny sample of paint and mount it up in cross-section and polish it so that we can look at the layers side on. Just like when you slice into a cake, you can see the layers side on. And so that's what I've done here. This is not a sample from a Matisse, which is good because it's undergoing a very bad degradation problem. In this case what we're seeing is that the lead white in the ground is reacting with the oil binder to form these large blobs, for lack of a better word, or spheres, of lead carboxylates. And they grow large enough that they actually wind up protruding through the top layers of paint. And the painting winds up looking like it has little white freckles all over it. And so the best example of this that I can give in this time period is John Singer Sargent's portrait of Madame X, which if you saw it in its unreserved state has white freckles all over the surface of the painting because of this phenomenon. And so this is something that typically is seen in Dutch Golden Age paintings, but we are starting to see it in turn of the 20th century paintings as well. Okay, so going back to Le Bonheur de Vieve, as probably most of the people in the audience knows, this was painted at a time that was a difficult time for Matisse in terms of to say he was not getting critical recognition, he was probably putting it mildly and that of course had financial implications for him. And in 1925, he gives an interview where he talks a little bit about his financial circumstances and the financial circumstances of his colleagues during that time and points out they didn't even have enough money to buy a beer. So things are serious. And then he goes on to say that his contemporaries were having problem buying the pigments that they needed. And he notes especially that the cadmiums were quite expensive. And so when you look at the dimensions of Le Bonheur de Vieve, it's monumental. You can imagine how much cadmium yellow is needed to cover the canvas. And so there's a potential that we could have run into a problem with the stability of the cadmium yellow that he used as we'll see. And of course, Le Bonheur de Vieve has been called recently the single most consequential early modern painting and it's really tremendous in terms of its impact in modern art. And unfortunately, as Barbara showed us on Thursday night, the condition has extensive regions of lightning or fading and then also discoloration, as you can see in this image up here and then also in this image here. And we'll go over those regions closely and talk about the chemistry behind what's going on. Okay, so this was one of those projects when I came to visit the barns and worked with Barbara in November of 2006. And like Angelica Ruenstein, we walked into the room and said, everyone knows chrome yellow is unstable. This is gonna be chrome yellow. This project is gonna take about six hours and 10 years later, here we are still working on it. So you could never predict how complex the painting degradation is going to be when you start a project like this. But we were really, really fortunate to have an international team of colleagues working with us on this project. And we wound up taking samples out to Stanford University to study them there to a particle accelerator in the south of France, which felt very strange taking these tiny flakes of Le Bonheur-de-Viv back to the south of France so that we could study them there. And we often wondered what Matisse would have thought of that process. And you can see how much younger I am in this picture here. Okay, so first an overview of the palette before we get very deeply into the degradation phenomena. So I've listed the palette here and it's essentially what we would expect from Matisse in terms of very pure, very bright colors, the only evidence of mixing other than in the tree here that Barbara pointed out on Thursday night is we have a little bit of lead white mixed in with the synthetic ultramarine. But otherwise it's really an exceptionally pure palette. You can actually see in this image here of cadmium orange these large particles in the ground layer and that's barium sulfate mixed together with lead white in order to form the ground. So we can see in the cross section of the tree in the upper left corner that's darkened so badly that darkening layer and then a little bit of restoration that's been applied on top of it. This is our Viridian green and this is actually cobalt violet on the surface and we're looking at Matter Lake at the bottom and so that comes from this area of the figures right here and what's kind of amazing is that this is the sample invisible light. That's the same sample viewed in ultraviolet light and you can see that Matter Lake has this wonderful bright orange fluorescence in ultraviolet light that allows us to pick it out and this is really important because I put a star by Matter Lake and a star by Cadmium Yellow because these are the two most sensitive pigments in the work and so identifying where those pigments are located is critical to us in order to monitor the condition of the work over time. I also wanted to point out in this sample, can you see that thin white line that's on the surface of the sample? That's residual varnish and so as Barbara mentioned on Thursday the painting is largely not varnished anymore but at one point it was varnished and that varnish was partially removed and so we see little bits of evidence of it and the fact that it fluoresces white like this means it's a natural resin varnish like damar or mastic. If we look at the Cadmium Yellow samples such as this one for instance and this one, you can see that white degradation layer that's growing on the surface of this beautiful bright yellow color which is how we wind up with these large passages looking white that used to be this wonderful deep Cadmium Yellow. This is carbon black with a little bit of Cadmium Yellow on top. It's taken from that one underdrawing brush stroke right here and so this is the sample invisible light and an ultraviolet light and you can see again that orange fluorescence of the Cadmium as it degrades when we look at it in ultraviolet. So we have these little cues in ultraviolet in terms of the materials that are starting to change over time. Okay, so if we compare the four different versions of the painting in the monumental work at the Barnes, that's where we see below the central figures not only fading but also physical changes such as flaking and spalling. Spalling is kind of a materials engineering term for where you have larger flakes that are coming off the surface of the object and in the upper left corner, the surface you can see is very modeled and we wind up with these tan ochre hues that Matisse never intended. I'll get the other works up here and Copenhagen really has a number of different hues that you don't see in the Barnes version and so SF MoMA is really the closest in terms of trying to understand what Matisse's original intent was for Le Bonne or De Vieve and so I think this is a very good comparison work and we'll see that this painting is obviously undergone a fair bit of photo degradation, light induced degradation and we're gonna see that the SF MoMA painting is just starting down that same road and it's undergoing incipient degradation is what I call it and this is really the ideal situation where we can catch the degradation just as it's starting and start to figure out the right environment in order to stop the degradation from continuing because if you look at the San Francisco painting it looks like it's in excellent condition, there's no visual evidence of any change that's occurred yet. Okay, so we identified three major problem areas in Le Bonne or De Vieve. The first is the foliage in the upper left corner and this gives you a closer look at it and then there's the fruits and you can see the fruits in the tree have developed this sort of dirty ivory alteration crust over what would have been a beautiful warm yellow like I showed on the last slide and then underneath the central figures we have basically sort of a dirty ivory color that's formed over a skin over the original bright yellow paint and the high impasto regions, the very thickly painted regions as if you were icing a cake and making very thick swirls of icing, those are the heaviest regions of paint on the painting and so they actually start to flake off as the discoloration is occurring and that's why you see some areas that really do have the original bright yellow surrounded by areas where the bright yellow is obscured by the degradation products. Okay, so the first thing that we did was totally non-destructive, an x-ray fluorescence technique and the way this technique works is we're hitting the painting with a high energy beam of x-rays and we're not even touching the painting, it's totally non-destructive and then we're looking at the energies of the x-rays that come off the surface of the painting and so that's plotted on the horizontal axis here and so the position of the peaks on the horizontal axis tell us which elements among all of the different elements in the periodic table are actually present in the painting and so what we can see in the area that's darkened, high concentrations of cadmium and in the area that's faded, again, high concentrations of cadmium and this was really bad news not only for these works by Matisse but also because this pigment was so favored also by Picasso and Monet, just literally dozens of artists in the turn of the 20th century whose works are now going through the same or very closely related degradation phenomena and this is not all the x-ray fluorescence data that we took and so for example, this is all chrome yellow what we expected to be bad but as Barbara mentioned is in terrific condition and then the cadmium yellow also extends to the area around this crouching figure here and so the way we used to put it is all of the areas that have changed are cadmium yellow but not all of the cadmium yellows have changed and so we still have some cadmium yellow intact on this painting like this area here is all cadmium yellow this area here is all cadmium yellow too Okay, then we did a very simple experiment where we took a tiny flake of the paint from this faded region here and we put it into an electron microscope where we could look again at the x-rays that the pigments give off and compared that just to a tube of cadmium yellow that I got from the art supply store well cadmium yellow has a cadmium and it's cadmium sulfide and the cadmium to sulfur ratio should be one to one and that's just what we see in the cadmium yellow that comes from our paint tube but if we look at the cadmium yellow from Le Bonheur de Vieve that's undergone these drastic changes look at the ratio of cadmium to sulfur there's really almost no sulfur left so we still have cadmium compounds there but not very much cadmium yellow so next we turn to molecular analysis where we were going to identify the molecules that were present based upon their characteristic molecular vibrations and so this shows a little some of the different vibration processes that we measure I know how to turn these on I don't know how to turn them off so you'll have to figure it through with these things wiggling during the slide so what we found in infrared spectroscopy and now in this case the horizontal axis represents different molecular vibrations and the data from Le Bonheur de Vieve is shown in purple that it was a perfect match for cadmium carbonate we were concerned that we were seeing calcium carbonate because that is that common paint filler but we didn't we have cadmium carbonate instead and cadmium carbonate is a white compound and so that could be one reason why this is starting to fade away but we needed more evidence than that in order to understand the degradation mechanism so then our little flake of yellow paint from under the central figures traveled out to San Francisco with us so that we could study it at the synchrotron which is a particle accelerator at Stanford University and when we used an x-ray absorption technique called Zanes at Stanford with our wonderful collaborator, a pervameta what we were able to get is a local composition for the composition of the paint in that area and what we found was not so great only 14% of the cadmium is still cadmium yellow and we had nearly 70% of the paint is cadmium carbonate and 17% is cadmium sulfate and so the paint is now mostly changed into other compounds the sulfate and the carbonate the sulfate and the carbonate are both white and so having those compounds form over time would certainly explain the color change that we're observing and to give you a sense of how this process works these are basically the three reference compounds that we studied, the sulfide, the sulfate and the carbonate the data from the painting is shown in black and then we do a linear combination of these three reference standards until we get a perfect fit for the sample from the painting and so that's where these numbers come from so we found these compounds and now if we truly do have a light induced degradation phenomenon they should only be present on the surface of the painting and so that was the next thing we had to look into okay so this is one of those cross sections again taken now from the area of the fruit where the cadmium yellow has started to change and develop this crust and what you can see invisible light under the microscope is the alteration crust growing on the surface and the paint perfectly intact underneath if we look at the sample in ultraviolet light again we get this crazy fluorescence this is a result of cadmium sulfide being a semiconductor and I won't go into the details there but it's a great way to identify whether or not you have cadmium yellow in ultraviolet light you can also see in the ultraviolet image when the chemical change occurs a physical change occurs as well the volume is larger for cadmium sulfate and cadmium carbonate than it is for cadmium sulfide so the paint layers actually start to expand and crumble and so that's what we're seeing in this area here the paint is expanding and of course here it's starting to fall away completely so we went back to the electron microscope to see if we could understand the composition of the alteration layer at the surface versus the interior where the paint is intact and what we're looking at here is a map of the elements cadmium and sulfur where cadmium is shown in red and sulfur is shown in green and what you can see is that where the sample is yellow the cadmium sulfide is very well intact but if we look at the alteration areas where the paint has turned white then what we can see is the sulfur is almost completely gone and so this very much is a chemical reaction that's happening from the surface of the painting down into the interior and we could also see the physical degradation of the paint layer as well and so if we focus in on this area right here which looks white it's definitely chemically degraded what we can see in what's called the backscattered electron image a very highly magnified image of the paint sample look at all of these cracks running through the paint sample in the area where the degradation has occurred and so the chemistry, the chemical changes are directly related to the physical changes that we're seeing in the paint layer and what this means when you look at the painting is you see chalking the paint starts to look very crumbly and dry and then ultimately it does start to crumble off the surface of the painting we think what's going on here is that the oil binder is actually being attacked by acid as sulfates are released by the cadmium sulfide and so this is another degradation mechanism that I didn't even talk about at the beginning here we have a pigment that's actually chemically reacting in an unanticipated way with the paint binder the other thing that was really interesting if we study this area really closely under the electron microscope and now map oxygen in blue is that you can literally see in the area where the paint is crumbling that the sulfur from the cadmium yellow is being replaced by oxygen so this is quite literally a photo oxidation of light causing oxygen to react with the surface of the painting alright so now it was time to take our same paint sample and travel to the south of France and use a particle accelerator that called ESRF the European Synchrotron Radiation Facility that has an X-ray beam one one hundredth the size of a human hair and so with such a tiny tiny X-ray beam we were able to look at individual spots on both the degradation layer and the intact paint and the first thing that we could notice if you look at the degradation layer cadmium yellow is totally gone it's completely been replaced by cadmium carbonate and cadmium sulfate and so that's the composition of that white alteration layer on the top of the painting that we now look at when we view the painting particularly under the central reclining figures in the area where the paint is still yellow then we see there is some cadmium sulfide left 20% here 37% here so not a lot but enough to make the paint still a bright yellow and then this is also that same infrared spectroscopy where we're using molecular vibrations in order to identify the different phases that are present and what we could see was not only the cadmium carbonates and sulfates but also cadmium oxalates as well oxalates form an oil painting as the binding medium the oil is attacked and so this was further evidence that as the pigment degrades the oil binder is being attacked and these different colors represent the colors in the map that we're seeing here and so you can see the oxalates are forming at the very surface so in order to get these images basically what we did is we sliced the face off of the sample and then crushed it between two diamond cells which is why it loses its morphology here and then the sample is thin enough to allow the infrared radiation to pass through it okay so we understand now at a microscopic level what's happening to the Bonner-DeVee and now I wanted to understand at a macroscopic level how we can identify these changes in all four versions of the Bonner-DeVee so that we could say something about the state of preservation of these paintings and make recommendations in terms of the future storage and display of these works so that they can be kept safe for future generations so we tried a number of imaging techniques this is what the small piece of the painting looks like in visible light and then we also used a technique called ultraviolet induced infrared fluorescence so we're exposing the painting to ultraviolet light and then looking at it the fluorescence that comes off in infrared light and can you see this area where the alteration crust has flaked off and it's still bright yellow? That shows up very nicely in the infrared but unfortunately this is all cadmium yellow too and it doesn't show up in the infrared so this is not a very comprehensive way to study the painting and the same thing that happened when we used ultraviolet induced visible fluorescence so we get this beautiful orange fluorescence in the areas where the yellow paint is pretty much showing through but all of this is cadmium yellow as well and it doesn't fluoresce and the reason for that is that the orange fluorescence is due to the presence of cadmium sulfide but the top layer of the painting is now cadmium sulfate and cadmium carbonate so we need to look at another way in order to study these paintings and that turned out to be multispectral imaging which we did with our colleagues from the National Gallery of Art and what we're doing is exciting the painting not necessarily with ultraviolet light this time but with a slightly lower energy radiation essentially blue-greed light and then recording the fluorescence from 650 nanometers, 700 nanometers and 850 nanometers so if we look at the central figure reclining figure with the black hair and Barbara mentioned that she should have two halos now when we use multispectral imaging the two halos show up perfectly the top halo shows up as blue and the bottom halo shows up as kind of a greenish color and now all of the cadmium yellow fluoresces when we use this technique and this technique actually goes deeper into the painting than the ultraviolet light does and so it allows us to image cadmium sulfide even though it's now buried beneath these degradation products and also you can see the circle of dancers in the background of the painting the specific lines that are actually painted with cadmium orange, they fluoresce as well and then the crouching figure in the foreground you can see that this was all cadmium yellow in this area as well and so a very good way to identify cadmium yellow comprehensively on a large work so if we turn now to the Copenhagen version of the painting what you can see looking at it just in a superficial way is that not only are the hues quite different than what we see for the Barnes painting but also it looks like it's in excellent condition and sure enough what we see is the paint surface is actually extremely glossy and intact and one thing that I haven't mentioned so far is that in Matisse's time if he were to go to the color men or the art supply store he would have had a choice of seven different cadmium yellows that he could purchase all the way from a lemon cadmium to cadmium orange essentially and it's the palest cadmiums that tend to undergo the most significant degradation and so in this case what we see is that he's not actually using a pale cadmium yellow he's mixing cadmium yellow, a dark one with a white paint and that could be one of the reasons why this particular painting is in such good condition and if you compare them side by side we don't have any of the evidence of the flaking or the chalking or the fading or the discoloration that we do see in the monumental Barnes work and so we studied this painting under ultraviolet light and there's no evidence of the orange fluorescence of the degraded cadmium yellow it's the painting is in perfect condition it's absolutely intact and in order to think about why this might be the case this was of course painted in the south of France and the Barnes painting was painted in Paris and so there's the possibility we can't know for certain but the possibility that he was using two different sources of cadmium yellow for the two different paintings and then likewise when we look at the infrared fluorescence of the painting it's perfect we don't see any evidence of bright spots showing up where the degraded cadmium yellow is starting to fluoresce where things get really interesting though is when we go to the SF MoMA version and I love this version an oil study for the monumental landscape at the Barnes but look at the condition of the pigments this I think is Matisse's original vision for this painting for example look at the matter lakes and what a brilliant pink color that they are and look at the condition of the cadmium yellow it's in just phenomenal shape and of course it's a neo-impressionist work so it's got a lot that's very different than the Barnes work but I think it's very informative in terms of original vision and if you do the side by side comparison you can really get a sense of how the Barnes painting has changed compared to the SF MoMA where the retention of color again is excellent and this is Paula de Cristofaro paintings conservator at SF MoMA that helped us with this research but there were tiny brushstrokes on this painting where we could see where something was starting to go wrong and so for example we have the orthogonal network of cracks in this brushstroke here and this brushstroke you might think oh it's just kind of dirty maybe there's some residual varnish there these little brown areas here but we also had to consider maybe we're seeing photo degradation in this area and the same thing is true we're now up above the embracing figures here and we have this one brushstroke it's difficult to see in visible light that looks a little bit dirtier than the surrounding brushstrokes for no particular reason there's no reason why that brushstroke should be dirty the other one should be in such good condition and sure enough if we look at the painting in ultraviolet light just that one brushstroke lights up like a Christmas tree and that tells us that the cadmium yellow is actually starting to undergo photo oxidation in that one brushstroke and so this is a critical point in the lifetime of this painting where the paint is starting to degrade but it's not yet visible to the naked eye and so it's a wonderful opportunity to really start the preservation of this work and in this case we really think what we're looking at is photo degradation and not something like a change in the paint source to a less stable paint source for example because you wouldn't see that in just one dob right in the center of the painting here and the same thing is true in the area below the central reclining figures that one brushstroke that looked a little bit dirty it shows up as orange in ultraviolet light and it shows up as bright white if we look at it in the infrared and so even if you just have an ultraviolet light that you can buy on Amazon for maybe $30 for example we have this incredibly accessible way in order to understand the state of preservation of these paintings and so you can go into a collection where you're concerned about this problem which is largely confined from the 1880s to the 1920s but has become a phenomenal problem for the works of the impressionists and the post-impressionists and the Fovests and really quickly identify areas where this type of photo degradation is going on and so we have this really accessible way to identify the problem and then we can get into the micro analysis to understand what is causing the problem whether it is the presence of oxygen or not in addition to light because some of these chemical changes are photo oxidations and others are photo reductions and how we would preserve the painting depends on the mechanism that we see. So where are we now? Well, what we're hoping will happen is a reinterpretation of the Barnes version of Le Bonheur de Vives because a lot of what's been written about this painting in the last 20 years or so is actually people reacting to the alteration of the painting and not to Matisse's original intent and so we'd like to put this painting really back where it belongs in terms of understanding that this painting actually was very balanced and it's been said that this painting now has sort of an acidic overall tone to it and that's a response to the very warm Academy of Yellows having faded away because the chrome yellows by themselves are very lemony and acidic and so the balance of the work is thrown off and that's something that with for example Photoshop reproduction we can change and get people to understand what this originally looked like and of course preservation was a critical outcome of the study now you can see it reinstalled as Barbara showed us with substantially lower light levels and so we are going to be able to preserve the condition of this work for future generations. In terms of can the damage be reversed? Likely not because we're losing so much of the sulfur that is a main component of Academy of Yellow so chemically it would be extremely challenging and dangerous to go backwards and so it's kind of like what you see with Van Gogh and the fading of his eosin red or Jureanium Lake you might have heard it called where they do digital reproductions or Photoshop reproductions to show what the artist's original intent was and so I think we're at a very exciting time now that we know that this is going on we can start to look for it in other collections and make sure that it doesn't progress to the level where it starts to disfigure the painting. There were so many collaborators for so many different countries that were involved in this project that I'd like to move straight to the money people and thank the Mellon Foundation, the Lenfest Foundation of course the Barnes Foundation and Angelica Brunstein who was such a driving force behind this project and thank you all so so much for your interest.