The Use of Science in Determining Value
Science can play an important role in the preservation, history, and authenticating of our Antique Egyptian reliefs. From a scientific standpoint, Professor Patricia Jue of the Chemistry Department was able to assess the deterioration of the objects and, along with Sharisha Guarneiri, determine the best possible method for storing these fragile relief sculptures. Science clearly is essential for the preservation of these objects. Another area in which scientific analysis proves helpful is in determining the history and authenticity of the sculptures and their pigmentation. It is important also to be able to determine the authenticity of these pieces, and in cases such as ours, connoisseurship is often the most common technique used. Connoisseurship is a valuable tool, but it is not always definitive. It is often based purely on human judgment and personal opinion, which can be swayed by external factors. This is where science can again prove fruitful in using chemical analysis in order to make determinations about our reliefs that could not be found through the eye of a connoisseur.
By simply looking at our reliefs we can determine some information about the limestone and pigments. The first is that our reliefs are not highly fossilerous, having many visible layers of fossils. This is a good sign because most fakes were carved out of limestone that was fossilerous. Also, by looking at the reliefs, there are several pigments evident on the surface. Certain reliefs have visible coloring, for example 1966.1.882, which clearly has browns, yellows, reds, and black. Others have traces of colors or black lines that have faded over time and are less prominent. We can determine from the visible colors that these are likely earth pigments.
Earth pigments have been used since prehistoric times as artistic pigments because of their availability, high coloring capacity, and their stability in varying weather conditions. The pigments we likely see on our reliefs are umbers, siennas, and ochres. These types of pigments are created using ground earth or clay mixed with spit or animal fat. We can also identify carbon black on many of the reliefs, which is made by heating wood or plant material with restricted air (Douma). All of these pigments are easy to use and prepare, making it difficult for us to determine the location from which the pigment was extracted since the ingredients can be found anywhere. Sometimes pigments can provide clues to finding forgeries based on the materials available in particular regions and time periods. If materials in the pigments that were not used in Egypt during Antiquity were discovered, we would be able to label them as fakes.
Analyzing the composition of the pigments could be useful in determining possibly where the paint was added. The best tests to carry out the analytical characterization of natural earth elements are scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and x-ray diffraction (XRD) scans. Testing the pigments could possibly establish a relationship between the source and composition of the earth pigments (Genester and Pons). This would be helpful information because by concluding the origin of the pigments we could establish if some are forgeries. If the pigments present originate from somewhere other than Egypt we could determine them as forgeries. Colgate has the proper instrumentation for these tests, but these tests would be destructive to the reliefs. In some cases this would require removing generous samples and sample preparation could require coating the sample.
An alternative to testing the pigments would be to perform tests on the limestone. This would not be destructive because in the repacking of the objects, samples of the stone were collected from each of the reliefs that had flaked off while wrapping. SEM and XRD testing would be useful for testing the limestone, though it would require preparation as well as a great deal of skill and training. The mineralogy of the limestone could provide us with some information about where the stone came from by matching our reliefs to limestone deposits in Egypt. Based on literature of limestone deposits (Middleton and Bradley). Even if we were able to find a match to a limestone deposit, the limestone could be quarried miles from where the sculptures were made and this could not determine forgeries. Therefore we would not be able to deduce where the sculptures where carved, just where the limestone itself came from. This would be helpful, similar to the pigmentation source, in identifying forgeries but would not give us an exact time period from which the sculptures were made.
Providing a source for the limestone or pigments could help in dating the reliefs to a certain extent, but there is much error in this method of dating. A more accurate method of dating the reliefs would be to carry out Carbon 14 dating. This method would allow us to directly date organic carbon black pigments on the reliefs. This would allow us to date them to centuries back with little error. We would need to sample from each relief and scrape the black powder from the limestone in order to test. This long process “aims to separate a sample’s inorganic carbon coming from the limestone support (calcium carbonate, CaCO3, not useful for dating) from the pigment’s organic carbon component” (Douma). Unfortunately we do not have the instrumentation for carbon dating at Colgate and this would have to be performed at an outside laboratory.
Testing and removing samples brings up an ethical dilemma. “Testing pigment would require removing samples from the objects. Since there is very little pigment on most of the objects, and much may be original, I believe it would be imprudent to remove any pigment until we have a very good idea of the value of the objects” (Patricia Jue, Chemistry Department). Testing the pigments would possibly bring about valuable information such as the origin of pigments or limestone and the more accurate dating of carbon. Due to the destructive nature of some of these tests, many scholars are reluctant to test our reliefs scientifically before knowing the ‘value’. We are afraid to ruin the value of these objects by removing samples, but the value of our reliefs is very little if we do not know their history.
It seems that the information we would learn from scientific testing would be fruitful enough to be worth the sacrifices of destructive testing because it would increase their value in many ways. It is important to not discredit the benefits of scientific analysis in determining our sculptural reliefs’ history. Testing the reliefs could increase the value of the objects by confirming their history and possibly even authenticity. Therefore any scientific test that could provide useful information about our reliefs’ should be carried out despite this dilemma of determining the value first. Determining specific information about these sculptures through scientific analysis would determine a certain value, monetary and scholarly, that would help us move forward in the research and exhibiting of these reliefs. The benefits of scientific testing and how we could move forward with that information, by sharing our findings in an exhibit that would follow Mayer’s original intentions for the reliefs to be a teaching tool and adding to this area of scholarly work, would only make these reliefs more valuable.
Jamie Dal Lago '13 is an Art History Major and Film and Media Studies Minor at Colgate University.