Norbert S. Baer

Indoor air pollution: Effects on cultural and historic materials

Although the development of central air-conditioning systems some 50 years ago caused substantial attention to be paid to the effective control of the museum environment, interest in air pollution damage to art works predates that development. They discuss individual pollutants (sulfur oxides, nitrogen oxides, etc) as well as categories of indoor pollutants (those emitted from building materials, those emitted by artifacts, etc.). Tables provide data on air quality criteria for museums, archives, and libraries, as well as indoor air pollution damages to specific materials.

Pyrolysis gas chromatographic studies on Egyptian archaeological specimens: Organic patinas on the “Three Princesses” gold vessels

Abstract In 1916 a tomb in Egypt of three foreign wives of Thutmosis III was discovered and looted by robbers. Soon after, objects including gold vessels purporting to be from the tomb, were offered to the Metropolitan Museum of Art. In the mid-1970s the museum began a comprehensive study of this so-called “Three Princesses” Treasure. There soon was a growing realization that some of the gold was of modern origin. In a recent study using pyrolysis gas chromatography (Py-GC) we found that the organic patinas on all of the faked vessels gave virtually identical pyrograms; these in turn are very similar to pyrograms of standard mixtures of salts of long chain fatty acids. Further, the pyrograms of the patinas were identical to pyrograms of the organic contents from one of the jars from the same find. Py-GC made it possible to establish the identity of the patinas and the jar contents quickly. Further analysis by conventional methods was undertaken to identify the composition of this material.

Application of pyrolysis-gas chromatography and pyrolysis-gas chromatography/mass spectrometry to the unmasking of amber forgeries

Abstract Attempts to forge amber inclusions have been known from ancient times, when natural materials such as melted amber or copal were used. At the very beginning of the Twentieth Century these natural materials were mostly replaced by Bakelite and similar synthetic polymers. These materials are not transparent and so can readily imitate certain kinds of milky amber but are useless in terms of transparent ambers with inclusions. In the 1940s two new classes of organic materials became available for amber imitation, i.e. polyester resins and epoxy resins. Both are transparent, able to dissolve organic dyes and can achieve an appropriate degree of hardness, depending on the addition of fillers (e.g. fiberglass), the structure of the original monomers, and the degree of crosslinking. With easy commercial availability and sophisticated “artwork” one can prepare convincing imitations of large transparent amber pieces with a wide variety of “inclusion” (ants, bees, lizards, mosquitos, etc.). Py-GC provides a simple test for the unmasking of such fakes, and Py-GC/MS can identify quite precisely the structures of the materials used for these purposes. A growing number of fossil forgeries produced in the Dominican Republic, and sold there and in New York, have been documented. The results reported are based largely on forgeries acquired by D. Grimaldi specifically for this study and kept at the American Museum of Natural History in New York; and from the Conservation Centers collection of forged artifacts and jewelry made available by New York galleries and private collectors.

Currency features for visually impaired people

The estimated 3.7 million Americans with low vision experience a uniquely difficult task in identifying the denominations of U.S. banknotes because the notes are remarkably uniform in size, color, and general design. The National Research Councils Committee on Currency Features Usable by the Visually Impaired assessed features that could be used by people who are visually disabled to distinguish currency from other documents and to denominate and authenticate banknotes using available technology. Variation of length and height, introduction of large numerals on a uniform, high-contrast background, use of different colors for each of the six denominations printed, and the introduction of overt denomination codes that could lead to development of effective, low-cost devices for examining banknotes were all deemed features available now. Issues affecting performance, including the science of visual and tactile perception, were addressed for these features, as well as for those features requiring additional research and development. In this group the committee included durable tactile features such as those printed with transparent ink, and the production of currency with holes to indicate denomination. Among long-range approaches considered were the development of technologically advanced devices and smart money.

Use of tombstones in investigation of deterioration of stone monuments

A number of researchers have used tombstones to study the deterioration of stone. The tombstones can provide a large number of samples for statistical analyses. Measurements have included index of legibility, microrelief of resistant inclusions, and loss of thickness. Lack of information about past exposure conditions makes it difficult to derive quantitative relationships. The most useful results involve ranking of stone durability, and identification of time periods or geographic regions with high rates of stone deterioration.

Volatile amines used as corrosion inhibitors in museum humidification systems

The importance of controlled environmental conditions to the preservation of cultural artifacts is well established. The most important factor in climate control is thought to be the maintenance of an optimum and stable level of humidity since fluctuations in humidity levels can cause deterioration and damage to artifacts. Maintenance of steady humidity levels is essential in museums situated in most of Europe and North America where uncontrolled interior humidity levels can exceed 80 per cent during humid summer months and drop to 20 per cent, or lower, during dry winter months where central heating is used. ’ The technology to control museum environments is relatively new, beginning less than

Risk management, value and decision-making

0 years ago with the development of central air-conditioning. Although the complexity and expense of specialized climate control systems has increased, the basic function remains the same: to introduce moist air into the environment with humidi~cation equipment during dry periods and to remove moisture from the air with dehumidification equipment during humid periods. At present, most museums maintain a controlled environment through central air-conditioning systems that circulate RH and temperature-controlled air filtered of particulate matter. In some cases gaseous pollutants, i.e. SO,, NO,, and 0, are removed.*

Air Pollution Effects on Physical and Economic Systems

Summary In over three decades of teaching at the Conservation Center of the Institute of Fine Arts, New York, the author has explored a number of organizing principles to synthesize the vast body of materials science encountered in the conservation of cultural property. Among these has been the concept of risk management as defined by various committees of the National Academy of Sciences. This led logically to the question of value and values. In the recent past, the author has engaged in interdisciplinary dialogue with economists, mathematicians and political scientists, considering mechanisms of decision-making in the preservation of cultural property. Using selected examples drawn from the assignments the author has given his students, the evolution in his teaching methods and the parallel evolution of the discipline of conservation are examined.

Conservation notes: microenvironments

Publisher Summary The visual quality of the atmosphere, consisting of its color and the clearness with which distant objects could be seen, is one of three measures of environment quality that are available to almost every member of the public whether they be trained scientists or not. The other two readily apparent air quality indicators are odors and large dust or soot particles. Material damage is measured by noting quantitative changes in some physical or chemical feature of the material. A wide range of sensitive materials could be affected by air pollution. Metals, masonry, paint and other coatings, other materials—paper, photographic materials, textiles, and leather— and cultural property—historically and culturally valuable structures and objects—form classes of materials that are used and are economically important. Monitoring methods that are designed for ambient air quality and occupational air quality are potentially applicable to the measurement of indoor air quality. Some of the special requirements of indoor air quality monitoring impose problems in this technology transfer. These problems are related to such factors as sensitivity, short-term response, multiple point monitoring at several locations in a structure, ability to depict human exposure, noise and other intrusions in occupied dwellings, prevention of contamination or change of the indoor environment by monitoring equipment exhaust or by removing excessive quantities of sample air from the indoor space with external samplers, and, as in any monitoring program, cost.

Forgeries of Fossils in “Amber”: History, Identification and Case Studies

Environmental standards are usually written for ambient conditions on the scale of a room in a museum, library or historic house, but it is often the microenvironment (exhibition case, box, compact shelving etc. That dominates the artifacts response to temperature and humidity. The authors review the results of studies of microenvironments for paper-based and photographic materials and provide a table of qualitative properties of protective enclosures and diagrams of gas migration in an exhibition case and a document box (with hand-hole). References. -- ICCROM