Issue1. Vol.1 (April, 2013) - IIT Mandi

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ESSENT Society for Collaborative Research and Innovation, IIT MandiHimalayas is reflecting a culture shockinglyalien to ours, the colorful paintings allow for adirect non-verbal access, revealing anenormously rich world. It was for me a truediscovery opening the door to a marvelousspiritual and artistic domain. I felt like “profanechemist” having gotten access to a spiritualparadise, to the “Pure Land” or Sukhavati, usinga Sanskrit Buddhist term.No, I did not convert into a Buddhist, nor am Iparticularly religiously inclined; but thisexperience widened my perception for spiritualconcepts and for non-verbal expressions ofeternal truths. While we chemists are usingchemical formulas for representing structuresand chemical reaction pathways, in the spiritualcontext, metaphors, symbols, and rituals haveequal importance to express abstractphilosophical concepts independently of aparticular language, and become universallyunderstandable. I was struck by a wealth ofsimilarities and correspondences betweenEastern and Western philosophies and religions.Having once become acquainted with oneparticular language or philosophy, one maycomprehend others without much difficulty;they all emerge from similar human minds anduse related symbols or metaphors.Since 1968, Magdalena and I have establishedin our home a sizeable collection of ancientTibetan and Central Asian, mostly Buddhist,paintings from the 12 th to the 19 th century.Today, they decorate virtually all the availablewalls. My curiosity was stimulated as much asby my first encounter with chemistry in the atticof our old house in 1945. I was inspired toacquaint myself with the complexity of CentralAsian history that evolved during the past 1000years; I had to learn about the depth of Buddhistphilosophy and symbolism in order tocomprehend the secret messages of the beautifulpaintings; and I got insight into the Tibetan lifestyle that is depicted in all details within thereligious and historical pictures. All aspects ofthe Tibetan daily life are intimately related tothe Buddhist view of life and tradition. This20 ESSENT|Issue1|Vol1renders these paintings invaluable sources onTibetan culture and philosophy in the past andpresent.Technically speaking, the paintings are skillfulproducts of "applied chemistry", of“Angewandte Chemie”. Here, the relationbetween chemistry and painting art is becomingobvious and highly relevant for art conservation.In the course of maintaining our preciouscollection of Central Asian paintings, I started torealize that art conservation is one of the mostdemanding scientific occupations conceivable.The range of relevant scientific aspects isbreathtaking, from knowledge of the paintingmaterials: support, grounding of the support (theso-called gesso), to the traditional binders and toa wide variety of natural and synthetic pigments.The application of quite delicate naturalpigments requires a lot of skill and experience,and chemical knowledge is indeedindispensable.After my compulsory professional retirement in1998, I set out to properly equip a small “artconservation laboratory” within our privatehome, converting a hobby crafting room into atiny specialized analytical spectroscopy andrestoration lab. I needed to add facilities for thechemical, microscopic, and spectroscopicanalysis of the paintings, for the cleaning of thepainting surface from centuries of surfacesoiling, for retouching minor damages of thepigment layer, and for repairs of the Chinesesilk framing of the paintings. Each stepcomprises of highly delicate and demandingaspects that can be handled only by experiencedexperts, who themselves are often coming totheir own limits of skill and expertise.Before attempting to consolidate or restoredamaged details within a precious ancientpainting, it is necessary to learn as much aspossible on the chemical aspects of the paintingmaterials that have been applied by the ancientartists. Obviously, of primary interest are thepainting pigments. My first acquired optical toolwas a Stereomicroscope Zeiss Stemi SV11 withobjectives, polarizer and photographic
ESSENT Society for Collaborative Research and Innovation, IIT Mandiequipment. The microscope was mounted on asufficiently large and stable mobile gantry tocover paintings up to 2 m 2 . A stereo microscopeis indispensable for the study of pigment layersand for the restoration of minor damages by avery fine brush and a tungsten needle.Initially, I applied my practical chemicalknowledge in wet chemistry, remaining frommy first semester chemistry lab course, toidentify under a Zeiss Axiolab microscope someof the pigments. In many cases, it was sufficientto identify a characteristic metal ion thatuniquely identified, together with its color, theinorganic natural or synthetic pigment. In thecase of blue pigments, for example, the presenceof copper verified azurite, iron led to Prussianblue, and aluminum to ultramarine or naturallapis lazuli. However, the application of myfirst-semester chemistry was invasive andrequired appreciable amounts of sample to betaken crudely from the painting. Performingcharacteristic color reactions under a stereomicroscope reduces the need for large samples;but in the case of the extremely fine Tibetan andMongolian paintings, where a painted eye mightconsist just of a single grain of pigment, thelimits of tolerable sampling are rapidlyapproached.My respect for the integrity of ancient paintingsforced me to switch as soon as possible to noninvasivemodes of spectroscopy without anyneed of sample-taking. Not all kinds ofspectroscopy are applicable for non-invasivelyexamining painting art. For example, mybeloved NMR, is often unsuited becausepaintings are too bulky for fitting into a narrowgapNMR spectrometer; and NMR techniquesare frequently not sensitive enough forexamining the thin layers of pigments appliedby the artist.The most ideal known analytical technique forpigment studies is Raman spectroscopy.Molecular vibrations are excited by a laser beamand the specific emission lines are observed.Raman is non-destructive, if used with somecare not to burn holes into the canvas by21 ESSENT|Issue1|Vol1excessive laser power, and it is truly a molecularanalysis technique, measuring indirectly thevibration frequencies of molecules or ofcrystalline material. Raman spectroscopy canalso be implemented on relatively small space,becoming the method of choice for the narrowanalytical laboratory in my private home. It wasnot too difficult to adapt a commercial Ramanmicroscope to the study of quite large scrollpaintings. The Bruker-Optics SENTERRARaman microscope was mounted on asufficiently spacious gantry to accommodatepaintings up to one square meter or more. Anydesired spot could then be reached by themicroscope objective under computer control.Sometimes, it is not even necessary to unframe apainting as the Raman measurement is alsopossible through a painting’s mineral coverglass, but not through Plexiglas.What has been the biggest influence andmotivation in your life that finallyculminated into a Nobel Prize?My biggest motivation was to do good and wellrespected work, so that I could become arespected citizen, overcoming my inferioritycomplex.What do you think is involved in being agreat scientist?I do not think that “great” is the proper term. Ithink it is sufficient to perform adequately andas well as ever possible. Properties such ashonesty, helpfulness, and compassion are ofgreat importance.NMR inarguably as a very powerful toolfor determining molecular structure hasrevolutionised chemistry. At thebeginning did you have the idea that itwould become such a powerful tool? Canyou briefly describe what brought you towork in the field of NMR spectroscopy?I did not choose NMR myself, I was pushed intoit by my supervisor, and I liked it. I did not
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Issue1. Vol.1 (April, 2013) - IIT Mandi

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