X-Ray Microanalysis of Art Glass
Figure 6: (A) Metallic surface produced on Effetre 271 Silver Plum glass (left) as opposed to the normal color of the glass. (B) X-ray spectrum indicating the presence of manganese and zinc along with silicon on the glass surface.
are generally considered safe for skin contact, and compounds of these metals are oſten used in dermatologic therapies. Lead, on the other hand, is not considered safe for human
contact. It has been banned from use in jewelry production and is currently the subject of restrictive legislation by the Consumer Products Safety Commission [2]. Te presence of lead on jewelry surfaces exposes the wearer to potential toxic skin contact. Contact dermatitis reactions to chromium, cobalt, or nickel in jewelry alloys also give a clear demonstration of this type of hazard. Metallic lead on exposed glass surfaces, while not a paint, might be interpreted as a coating and fall under the statutes outlined in the Consumer Products Safety Improvement Act (CPSIA), which limits the lead content of a surface on any material that may be contacted by children under 12 years of age to less than 90 parts per million as of August 2009 [3]. Producing and/or selling items with this type of surface might be interpreted as a violation of the CPSIA. Many glass workers assume that the disappearance of the
metallic sheen from reheated reduction glasses is caused by the metal melting back into the glass. Te fuming experiment demonstrates that lead is vaporized from the surface of the reduced glass, and lead vapor is present in the torch plume. Glass workers using inadequate ventilation in their work area will be exposed to varying levels of toxic metal vapors as well as other respiratory irritants in the torch plume. Te presence of these elements in this atmosphere underlines the importance of appropriate torch plume capture and exhaust from the immediate work area.
2010 September •
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Figure 7: (A) SEM image (BSE mode) of Kugler 215 (Gold Brown) showing bright islands on the surface similar to those observed on Effetre 456 (Figure 1). Inset image shows the silver surface that develops on this glass under reducing flame conditions. (B) X-ray spectrum indicating the presence of lead as well as silver in this glass.
Conclusion Te exact formulas for colored glasses have long been held
as closely guarded secrets. In the modern world, however, this information needs to be readily accessible to the end users of raw glass materials as well as consumers of art glass products. Consumers cannot depend on the color name or the surface color of a finished piece to determine the metallic elements present in the glass. Issues related to glass composition include safety and health considerations for the artist and the consumer, as well as possible legal implications for all concerned with the production and sale of these materials. Anyone working with these materials should familiarize themselves with the possible chemical hazards involved and take appropriate steps to ensure safe working conditions. Distributors and consumers need to have more information in order to make informed decisions about the use of art glass products.
References [1] C MacLeod, Technology and Culture 28 (4) (1987) 776–803. [2] U.S. Consumer Product Saſtey Commission, “Consumer Product Safety Improvement Act of 2008,” http://www.
cpsc.gov/cpsia.Pdf.
[3] U.S. Consumer Product Saſtey Commission, “Consumer Product Safety Improvement Act, Section 101,” http://
www.cpsc.gov/about/cpsia/sect101.html.
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