What is Coade Stone? When was Bakelite invented? What is the chemical structure of indigo? Is it safe to use mineral spirits? The answer to all of these questions and much more can be found in CAMEO, the Conservation and Art Materials Encyclopedia Online, available at www.cameo.mfa.org,  a set of Internet databases that serve art-related professionals as well as the general public.
Started in 1999 by the Museum of Fine Arts, Boston, the primary CAMEO database combines technical, historical, chemical, and visual information on historic and contemporary materials used in the preservation and production of artistic, architectural, and archaeological artifacts. With more than 10000 records, the knowledge base is broad—artifacts, sites, and treatment methods can include any combination of materials that have been used in the history of mankind. Additionally, the information required for conservation is becoming ever more complex and technical due to factors such as an increased availability of analytical techniques, the better understanding of deterioration processes, a wider selection of treatment materials, the new emphasis placed on preventive conservation, and ever-growing concerns about health and safety.
CAMEO entries include materials such as pigments, minerals, binders, coatings, adhesives, fibers, dyes, solvents, corrosion inhibitors, woods, pollutants, insects, pesticides, and storage materials. Each term was selected based on its mention in conservation literature, regardless of whether its use on objects or in museums is now considered ‘good’, such as Paraloid B-72,  or ‘bad’, such as DDT  or Soluble nylon. 
Examples of more materials and related terms in the encyclopedia include:
Materials used in the production, conservation, or analysis of historic and processed materials (stainless steel, eosin, Portland cement, plywood, Art-Sorb, acoustic tile, etc.)
Compositional groups (oil, alcohol, acrylic, aniline dye, polymer, etc.)
Chemical and physical classes (abrasive, detergent, sealant, absorbent, insecticide, etc.)
Analytical tools (hygrometer, X-ray fluorescence analysis, infrared spectroscopy, etc.)
Material characterization terms (hardness, gloss, porosity, refractive index, etc.)
Selected devices (Solander box, smoke detector, laser pointer, fluorescent lamp, etc.)
The primary description pages for each record contain a brief but comprehensive text about the general class of material along with its major use or biological source (see Fig. 1). For a natural product, its native geographical region is listed. Information is supplied about the material’s production, manufacturer, historical availability, appearance, and uses. For searching purposes, alternative, foreign, and archaic names are included in a synonym field, along with common misspellings.
Because of the condensed format of these descriptions, references, such as review articles, book chapters, and books, are included to direct the reader to more extensive information. Some of the references, such as the manufacturer’s Web pages, cited articles for the Journal of the American Institute for Conservation (JAIC), and Safety Data Sheets (SDSs), have direct hyperlinks to other Web sites on the Internet.
Several thousand images have also been added to CAMEO (see Fig. 2). Online thumbnail images can be enlarged with a click. These images provide an essential record of a material’s characteristics and include photographs and drawings of a material’s outward appearance, as well as analytical image records of a material’s microscopic and spectroscopic characteristics.
Examples of images in CAMEO are:
Images of artwork from the MFA’s collection that contain the material or have been treated or affected by the subject of the record (e.g., indigo, black walnut [see Fig. 2]).
Photographic images or drawings of minerals, gemstones, corrosion products, insect, animals, trees, and plants as well as processed products from these raw materials (e.g., quartz, ant).
Micrographs of minerals, metals, pigments, wood sections, and fibers, as well as positive and negative microanalytical results for spot tests and fluorescent staining (e.g., oak, cotton)
UV/Vis, infrared and Raman spectra of oils, resins, gums, waxes, proteins, pigments, dyes, and polymers (e.g., polyethylene, beeswax, realgar).
XRD patterns for minerals, pigments, and corrosion products (e.g., calcite, brochantite)
Comparative charts showing aging studies, stress curves, and product comparisons are also available. See for example, the records for blue pigments, gemstones, solvents and Paraloid.
In 2013, the CAMEO database was transferred from proprietary software and placed on a MediaWiki platform that resides on a cloud server. This transformation provided two significant changes for the active maintenance and growth of the database. First, it opens the database to data entry by many volunteer editors, whose updates provide the flexibility to keep editorial restrictions while also allowing easier, wide-spread contributions for revising and expanding the scope and content of our multi-functional information source. CAMEO currently has over 60 editors and that number is continually growing. Scientists interested in adding to the database are welcome to contact this author.
Secondly, the cloud server provides for virtually unlimited growth, which has placed CAMEO in the unique position to offer homes to small collaborative databases that benefit the conservation and museum communities. Two of the new major information resources are related to the use and analysis of natural and synthetic dyes in works of art. The first resource is the documentation of the Uemura collection of dyed fabrics that was acquired by the MFA in 2008. A database containing the original Japanese text with its English translation was created by Masumi Kataoka, Sherman Fairchild Fellow in Textile Conservation. Images of all of the dyed samples were collected by Keith Lawrence, scientific photographer. The second new resource is seminal to the scientific art analysis world because it provides critical analytical parameters for the analysis of synthetic and natural dyes using state-of-the-art liquid chromatographic and mass spectrometric equipment. This database initially will contain analyses carried out over the past ten years by Richard Laursen and collaborators at Boston University, comprising extensive work on many natural dye raw materials. Results from analyses of the Uemura archive carried out by Richard Newman at the MFA will also be included. It is anticipated that analyses from other researchers around the world will also be included in the future, making this CAMEO database an invaluable resource for high-quality information on the compositions of raw dye materials used throughout history, as well as samples from works of art that contain those dyes (see Fig. 3).
In 2006, the MFA formed a collaborative agreement with EU-Artech (Access, Research and Technology for the conservation of European Cultural Heritage)  to increase the international scope of CAMEO. In 2010, this partnership was redeveloped and extended with the CHARISMA (Cultural Heritage Advanced Research Infrastructures)  European research project consortium that focuses on providing transnational access, doing cooperative research, and networking applications in the field of cultural heritage conservation.
With this partnership, CHARISMA members have provided systematic review, correction, and update of the material records, including the introduction of records concerning examination and analysis techniques. The working group contributed European language synonyms, resulting in the addition of about 10000 non-English synonyms to the database as an aid for searching records. Now users can enter either English or non-English terms into the MATERIAL search box. Both the primary name and the synonym list are searched simultaneously, allowing for records to be retrieved by their Dutch, French, German, Greek, Italian, Portuguese, or Spanish names.
This collaboration helped expand the reach of the website into a broadly-used international resource. During the five year timeline of the CHARISMA working group project, CAMEO logged more than 1.5 million page hits in 219 countries. Further breakdown on the user distribution by Google Analytical statistics (Table 1) illustrates the impact that the CHARISMA work had on increasing the transnational use of CAMEO. The values for two one-month periods, January 2010 and January 2015, show the number and distribution of users of CAMEO at the beginning and end of the CHARISMA partnership. By percentages, the total number of users increased by 80%, and the relative percentage of the user pool outside the U.S. increased by 13%.
|Time Period||Sessions||Users||Countries||% Users Outside the U.S.|
Why is the technical information in CAMEO important for museums, and how is it used? Identification of materials in art is a significant consideration, but factors dealt with in the specialized field of preventive conservation can provide some insight into a few specific problems. An important goal of museums is to preserve their collections for future generations. In preventive conservation, the basic guidelines are to provide optimal environments for objects, thereby minimizing the causes of deterioration. These practices are widely considered critical for the cost effective preservation of large collections and are applied to the objects in storage as well as those on display.
To this effect, when sensitive objects go on display, they are placed in air-tight vitrines or display cases to provide physical safety while also creating controlled microenvironments that diminish pollutants, temperature and humidity fluctuations, and UV light exposure. Both high-tech and low-tech methods are used to create the environments. For example, some valuable organic materials, such as the Declaration of Independence, are stored in hermetically sealed cases that use oxygen scavengers to maintain an anoxic atmosphere. Also, it is common for display cases to be buffered at optimal levels using silica gel that has been conditioned to very specific moisture levels using saturated salt solutions. Controlled humidities are extremely important in many cases, such as where an archaeological ceramic with absorbed salts or a corroded sculpture with bronze disease must be kept at low humidities to minimize the formation of salt accretions or further corrosion. Additionally, vitrines containing objects made of silver or combinations of metals may contain scavengers, such as Corrosion Intercept, to hinder surface reactions.
Extreme care is used to examine all materials used in display case construction, since levels of any volatile components introduced in a contained atmosphere will be higher than levels found outside of it. Since the interior of a display case essentially creates a microclimate for the object, it can be disastrous if the materials used in the construction of the case release pollutants. For example, a common construction material is wood, but hardwoods, such as oak, release acetic acid, and some laminated woods, such as plywood, release formaldehyde and other reactive compounds. Vitrines can still be made with wood, as long as it is sealed with a barrier film, i.e., impermeable laminating material, such as MarvelSeal 360. A video on the Marvelseal 360 record illustrates the correct method for the application of this heat-seal laminate. 
It is standard practice to test all materials that go into a display case, whether it is the base, gasket, adhesive, fabric, or display label. For decades, a low tech method, called the Oddy test,  has been used to evaluate display case materials by placing them in a sealed test tube with small coupons of silver, lead, and bronze, then waiting for 6 weeks to see if any corrosion or tarnish occurs. Attempts to evaluate off-gassing of deleterious materials by other methods, including residual gas analyzers and sorbent tubes, have not been successful. Current hopes are leaning in the direction of a colorimetric sensor array developed by the Suslick group at the University of Illinois at Urbana-Champaign that uses an array of chemically reactive dyes that are specifically reactive to potential pollutants, resulting in a visual indicator of aerosol problems (see text box and references therein).
CAMEO is a readily accessible resource that defines, characterizes, and increases our understanding of the materials found in historic and artistic works. It provides a time saving resource for the conservation field, where knowledge regarding material properties, reactivity, and history can be crucial to success and safety. It also enables all interested persons to access vast amounts of technical and visual material data. This is especially beneficial to labs or museums with limited personnel or resources, as all sections of the database are free to users on the World Wide Web.
The database is now based on a MediaWiki platform and resides on a cloud server, placing CAMEO in the unique position to offer homes to small collaborative databases that benefit the conservation and museum communities. Continually growing, CAMEO has established a collaborative agreement with an EU working group of museum scientists to enhance the content, breadth, and transnational accessibility of the database. CAMEO currently has over 60 editors and that number is continually growing. Scientists interested in adding to the database are welcome to contact this author. The MFA is committed to providing CAMEO as an outreach program, with numerous benefits for professional conservators, the museum community, and the general public.
In November 2015, CAMEO was the subject of a online presentation hosted by Robert Belfort and part of the CCCE Fall Newsletter: http://confchem.ccce.divched.org/2015FallCCCENL. This feature for Chem. Int. was inspired by that presentation.
©2016 by Walter de Gruyter Berlin/Boston