Since its founding, The Metropolitan Museum of Art has been committed to the care and technical study of artworks in its collections. Museum staff played a pivotal role in transforming the craft of art restoration and repair into the profession of art conservation, which is based on modern advances in the material sciences. In the early 1960s a committee headed by Murray Pease, the first person to hold the title of conservator at the Museum, wrote a set of ethical and professional guidelines for the American Group of the International Institute for Conservation that continues to guide conservators today. These guidelines state that testing and treatment should only be undertaken
for "the preservation of the aesthetic, conceptual, and physical characteristics of artwork." As a result, examination techniques requiring little or no samples are employed before any treatment is undertaken, and minimal treatments are performed using materials that will not deteriorate, which was not always true of past restorations. Considerable attention is also given to the environments in which works are displayed, from the mounting and design of the exhibition casework to the light, temperature, and humidity levels in the galleries.
Conservators and conservation scientists made many exciting and interesting discoveries as they and the curators re-examined the Museum's collection of Islamic art prior to the reopening of the New Galleries for the Art of the Arab Lands, Turkey, Iran, Central Asia, and Later South Asia in November 2011. This exhibition and the accompanying lectures and gallery talks present some of their most interesting discoveries.
Although the human eye responds only to the narrow range of electromagnetic energy known as "visible" light, imaging using other wavelengths on the electromagnetic spectrum allows us to see the "invisible" in works of art. Infrared radiation, at wavelengths longer than visible light, can penetrate paint layers to reveal otherwise hidden preparatory designs. At shorter wavelengths ultraviolet radiation can reveal surface treatments and repairs, as well as highlight the presence of materials such as pigments, dyes, and metal leaf. X-radiographs, which have even shorter wavelengths, can uncover evidence of original fabrication and subsequent alterations. These different types of radiation are put to further use by the Museum's Department of Scientific Research. Museum scientists use instrumental analytical techniques to characterize and identify materials based on the specific interactions—including absorption, fluorescence, and diffraction—that occur between the radiation and the molecular or atomic components of an artwork. Sadly, the radiation in the visible and ultraviolet ranges that allows us to see and appreciate works of art can also be the cause of their deterioration. This is especially true for materials such as textiles, paper, and certain pigments and dyes. For this reason, works made with light-sensitive materials are exhibited under low light levels and for limited periods of time.