Chapter 15

Bridging the Gap of Art and Chemistryat the Introductory Level

Anne Gaquere-Parker*,1 and Cass D. Parker2

1Chemistry Department, University of West Georgia, 1601 Maple Street,Carrollton, GA 30118

2Chemistry Department, Clark Atlanta University, 223 J.P. Brawley Drive,Atlanta, GA 30314

*E-mail: agaquere@westga.edu

In institutions where non-science majors are required to enrollin a science course, especially chemistry, it may be difficult tocapture their attention and keep them interested in the topic. Anumber of different approaches have been used to capture theirattention and to achieve this goal. For instance topics such asforensics, food chemistry or green chemistry have been usedas the descriptive title to bring students into the classroom andprovide the vital connection of chemistry content. The authorsattended an NSF-sponsored CWCS workshop in 2006, ledby Drs. Patricia Hill and Michael Henchman which providedresources to teach a chemistry course for non-science majorswith the emphasis in art as the attractor and the chemistrycontent connection. Based on the general content from theworkshop and an expansion of the topic matter a non-sciencemajors course has been created and taught at the University ofWest Georgia ever since. This paper provides an overview ofthe topics and some of the contents covered in the Chemistry ofArt course at the University of West Georgia.

Background

Creativity is a fundamental precept of art and science! Yet, for a numberof people they are viewed and promoted incongruously with no commonality.However creativity in art has led artists to seek out the same in science to add

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to their palette colors and materials that will sustain and capture that creativity.Chemistry of Art is an introductory course that links that creativity of colors andmaterials to the basic chemistry behind it. As opposed to the traditional approach,this course shows that chemistry is intricately linked to art and in some cases theultimate basis for what we enjoy in an artist’s works.

Discussion

The background of students in chemistry for non-science majors’ courseis usually very diverse; it ranges from students who had many science coursesin high school, including AP chemistry sometimes to students who only had ageneral physical or biological science course. The class size ranging from 25students during the summer semester up to 75 during the fall semester as wellas the disparity in the students’ prior knowledge are true issues and they makeit difficult to keep all of them interested at the same time. One solution to thelatter problem is to broach topics in a nontraditional approach opposed to thetraditional taught in high school. The authors thus chose to cover specific topicsamong the large variety available for such a course. However, with the increasingnumber of articles, presentations and symposia on the topics of art and chemistryan instructor can tailor a course according to their audience (1, 2).

Elements, Properties, and Bohr’s Atomic Model

In Chemistry of Art the topic of elements and their properties are introducedfrom the standpoint of materials used in the production of an art piece. Adescription of the elements found in the periodic table can be linked to theelements found in jewelry, pigments and alloys and why they were chosen becauseof those properties. Copper is present in metallic alloys such as bronze and brassand also in green and blue pigments such as malachite and azurite. In some casesa historical event or archeological find is used in the introduction. For instance,mercury is present in the red pigment called vermilion widely present in thefrescos found in Pompeii, Italy. Discussing the fate of Pompeii is always of greatinterest to all students regardless of their personal background or chosen fieldand it keeps them engaged in the course. When one considers the large varietyof pigments available in the artist’s palette, one quickly finds an ample sourcethat allows the instructor to introduce and discuss chemical formulas, ionic andcovalent bonds, oxidation states and nomenclature of common polyatomic anions.When discussing Bohr’s atomic model the traditional flame test experiment canbe described in testing for metals present in a material, as shown in Figure 1.Naturally, students are informed that this kind of destructive test is not used forthe identification of artistic or historical objects.

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Figure 1. Flame test.

However a more unusual example linking color and metallic ions can be seenin stained glasses. The Sainte Chapelle built in Paris 1245, shown in Figure 2 or thework of Chagall in the Cathedral of Chartres can be used as examples to introducethe topic of metal ions, electronic structure, electron transition and electromagneticradiation absorption to give rise to colors. The understanding of materials andtheir electronic properties gives students a link to the importance of chemistry inproducing stained glasses and the research required to manipulate the chemistryto produce them.

Figure 2. Stained glass, Sainte Chapelle, Paris, France.

Acids and Bases Chemistry

Another important topic covered in a chemistry course is the one relatedto acids and bases. Of course, color indicators are a classic example that canbe used to introduce the topic in addition to more unusual examples such asthe action of acids on metals, the destruction and preservation of statues andpaper or the nature of acidic and basic organic dyes that have been used inthe production of masterpieces of art. The introduction of dyes as opposed topigments allows students to separate organic and inorganic chemistry into distinct

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fields of chemistry. The various acid or base functional groups found in dyescan begin the discussion of organic materials and their chemical properties, colorand permanence. The study of dyes provide students a perspective of how anunderstanding of chemical behavior and structure over time led to a much morediverse range of colors used by an artist. Student are made aware that many dyeswere first produced without any thought about their chemical structure.

Organic Chemistry

As organic and inorganic chemistry has been introduced to students throughthe topic of acids and bases additional selected topics in organic chemistry arealso taught in this course for non science majors. The subject matter of organicchemistry puts every student on the same level since it is very rare any incomingfreshman has had any organic chemistry prior to taking this course. In additionto the acid and base functional groups, additional organic chemical groups canbe described in a simple manner. Details about geometry and hybridization ofthe atoms are not necessary in such an introductory course. The primary goal isto introduce students to what functional groups are present in common materialsto the artist or non-artist palette and uses. Acetone, ethyl acetate, and terpenederivatives to cite only a few examples are described since they are commonlyfound in the painter’s studio as paint removers or thinners.

Dyes, used in the manufacture of the organic colorants for the artist’s palette,also can serve as a great source for teaching organic functional groups. Historicallythey have been extracted from plants, like the red obtained from the madder root orfrom bugs such as the red from the cochineal bug, as shown in Figure 3.a. Dyes arealso synthesized in the chemistry laboratory, like the famous historical landmark:the mauveine dye, as shown in Figure 3.b.

Figure 3. Molecular structure of organic dyes: (a) cochineal red and (b)mauveine.

Perkins’ synthesis of mauveine leads to a discussion on the history oforganic chemistry, which includes Wohler’s urea synthesis and its significancefor organic chemists. The description of organic dyes also includes a discussion

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on chromophore and auxochrome groups. Students in this course are alsotaught an introduction to spectroscopy as described later in this chapter. UV-visspectroscopy is used to show the effect of acids, bases, oxidizers and reducingagents on dyes and how that chemical change impacts the structure resulting ina change in the absorption spectra and ultimately to their observations of thematerial (3).

Carbohydrate and protein chemistry are also introduced in this course.Encaustics are produced using beeswax as a binder which may also containresidual sugars and honey. This discussion brings to bear the importance ofunderstanding the functional groups contained in carbohydrates and so thestructures of mono, disaccharides and polysaccharides are studied. In addition,the chemical composition of cellulose is provided to aid the discussion onwooden sculptures and cotton canvasses and textiles. Some knowledge of proteinchemistry is also provided since ancient glues were prepared from animal hides.We introduce students to the use of milk as a reported paint binder and textilesmade from silk that have been used as art supports. In addition to natural polymersbeing described as significant aspect and contributor to art as described in thiscourse, synthetic ones are also introduced. Indeed modern paintings may useacrylic-based paint and modern sculptures may contain plastic materials. Theintroduction to plastics is also used to show the difference between thermoset andthermoplastic polymers, their uses and preparation.

The last major family of biomolecules covered in the course is the lipid family.Lipid binders are the most widely used. We begin with the use of animal fatsused in cave paintings, beeswax, as mentioned earlier, used in Egyptian and Greekencaustics, egg tempera as the preferred media for painting up to the 15th centuryand finally drying oils. Examples of each media are included in the introductionfollowed by a chemical description of saturated and unsaturated fatty acids andtheir properties to explain the difference between drying and non-drying oils tothe students such that the oxidation process that occurs when oil paints dry can beshown.

Spectroscopy

The topics described above represent two thirds of the material presented tothe students during this one-semester introductory course. The remaining third ofthe course is dedicated to spectroscopy. Now that the students have a backgroundin chemistry related to the different classes of materials that can be found in a pieceof artwork, ranging frommetals to wood to egg andmilk, they are prepared to learnabout the technical analysis of works of art. UV- vis spectroscopy is presentedwhich provides a review of auxochrome and chromophore groups. This also leadsto a student understanding of how colors are viewed differently. Students arepresented with information that shows the variations in the spectra due to themodification of chemical structure as the result of pH or dilution effects, as shownin Figure 4.

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Figure 4. UV-vis spectra showing the effect of dilution on the cochineal red dye.

The use of dating techniques such as carbon dating provides a reviewon isotopes and atomic structure. A broader discussion on balancing nuclearequations, radioactivity, half-life and safety issues follows. Thermoluminescenceis also presented as a technique to date ceramics. Although the topic is notcovered in depth, it allows for a discussion on crystal lattices.

Infra-red spectroscopy is also covered and provides a great review of theorganic functional groups learned earlier in the class (4). Basic knowledge is givento the students who are then able to differentiate between the spectra of moleculescontaining common functional groups and recognize the specific peaks associatedwith them, as shown in Figure 5.

More sophisticated instrumentation is also discussed in this course.For instance students learn about x-ray spectroscopy. X-ray spectroscopyencompasses a wide range of techniques which can be connected to the technicalanalysis of the works of the cultural heritage (5). X-ray diffraction allows theinstructor to discuss crystal lattices as would be noted during the discussion ofinorganic materials. Bragg’s equation is presented to the students although noactual calculation used in crystallography is performed. However this allowsfor an introductory discussion in mineralogy and gemology. X-ray fluorescenceand laser ablation coupled with inductively coupled plasma spectroscopy arealso shown which allow for a review on atomic structure. Examples of varyingelemental compositions in coins or in pottery are given. The importance ofknowing the exact chemical composition of an artifact is emphasized as it canhelp archeologists establish ancient trade routes or forensics scientists detectfakes and forgeries (6).

Finally gas and liquid chromatography coupled with mass spectrometry(LCMS or GCMS) is introduced to the students. These techniques are largelyused in the technical analysis of works of art (7). The analysis of paint binders forinstance can be done by GCMS whereas dye analysis is carried out using LCMS.The spectra shown to the students allow for a review of molecular structure oforganic compounds, as shown in Figure 6.

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Figure 5. IR spectra of beeswax and paraffin wax.

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Figure 6. Mass spectrum of methyl linoleate.

With the appropriate set of data, the students can determine if the binder usedin a given example was egg or oil-based and also identify an unknown dye bymatching its mass spectrum with a known substance.

Conclusion

This introductory chemistry course, aimed specifically at art majors, allowsthe students to see the connection between chemistry and the technical analysisof works of art and more generally of the cultural heritage. Students from allbackgrounds benefit working with real-life applications of chemistry and bykeeping the students excited with cross-disciplinary examples. Two reflectiveexamples of comments written by students at the end of the semester are citedhere to show how they embraced the course: “The course is very interesting andmind opening” and “This was a very interesting course and unlike any othercourse I have ever taken regarding the material”. It is especially noteworthy toreceive such positive comments from the students enrolled in this course, sincethey are all non-science majors and mainly freshmen.

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References

1. Uffelman, E. S. J. Chem. Ed. 2007, 84 (10), 1617–1624.2. Uffelman, E. S.; Alty, L. T.; Fuchs, R. W.; Sturdy, L. F.; Bowman, D. S.;

Lemon, A. M.; Malachosky, E. W. Abstracts of Papers, 241st ACS NationalMeeting and Exposition, Anaheim, CA, United States, March 27-31, 2011;CHED-98.

3. Hill, P. S. The Molecular Basis of Color and Form: Chemistry in Art,Laboratory Manual; Millersville University, Millersville, PA, unpublished.

4. Derrick, M.; Stulik, D.; Landry, J. Infrared Spectroscopy in ConservationScience; The Getty Conservation Institute: Los Angeles, CA, 1999.

5. Uda, M.; Demortier, G.; Nakai, I. X-rays for Archeology; Springer:Dordrecht, The Netherlands, 2005.

6. Bradley, D.; Creagh, D. Physical Techniques in the Study of Art, Archeologyand Cultural Heritage, 1st ed.; Elsevier: New York, 2006.

7. Mills, J. S.; White, R. The Organic Chemistry of Museum Objects, 2nd ed.;Butterworth-Heinemann: Woburn, MA, 1999.

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