This site offers detailed information about the galleries and auction houses offering works by specific artists.
Another, less detailed, site offering subscription auction database information.
Blouin Art Sales Index
Previously called Hislop’s Art Sales Index, provides 5 million auction records for free
Getty Provenance Index Databases
Includes 1.5 million records taken from source material such as archival inventories, auction catalogs, and dealer stock books.
Previously called Artfact, this online auction marketplace includes fine and decorative arts, antiques, collectibles, and estate sales. Offers free, limited access and subscriptions for full access.
Lugt’s Répertoire Online
Online edition of Lugt's Répertoire des Catalogues de Ventes Publiques, fN8650.L8, v.1-4, Art/Classics, lists over 60,000 art sales catalogues dated 1600-1900 from libraries in Europe and the U.S.A. The catalogues provide information on the provenance of art objects, the history of collecting, and historical market trends. Numerous catalogues have been added to the original work and corrections made. Searchable by Lugt number, date, place, provenance, auction house and existing copies. In addition, the Libraries database allows the searching of libraries holding art sales catalogues. To search either Répertoire or Libraries, use scroll bar on left-hand side of page to scroll down to bottom to locate the two search bars--Click on either Search Répertoire or Search Libraries to open up a search window.
New York Public Library, Auction Sales Indexes
New York Public Library guide to auction sale indexes, price guides and catalogs. Because individual auction houses do not issue their own indexes, the use of these compilations provides the best approach to finding sale information. Each index provides different coverage in terms of dates, contents and scope. This guide includes the following sections: Chart of Subjects Covered by Various Auction Indexes; Current Auction Sales Indexes; Retrospective Auction Sales Indexes; Price Guides; Electronic Resources for Auction Sales; Publications of Sotheby's and Christie's.
SCIPIO (Access via http://www.lib.berkeley.edu/ARTH/ under Art History Resources/Auction-Related Information)
SCIPIO, or Sales Catalog Index Project Input Online, was formed to help researchers identify annually published auction catalogs; it is a particularly valuable resource for those seeking information on the provenance of art objects and rare books, connoisseurship, the history of collecting and collectors, historical and contemporary market trends, and the relationship between art and economics. Includes sales catalogs dating from the late sixteenth century to currently scheduled auctions. Important private sales as well as sale catalogs from all major European and North American auction houses are covered in subject areas of world art from all time periods, books and manuscripts, painting, sculpture, drawing, prints and photographs, furniture, decorative and applied arts, musical instruments, and objets d'art.
Condition also affects the value of artwork, and being able to identify condition problems can assist in the appraisal process.
Fine Arts Conservancy: Glossary
An illustrated dictionary of condition terms, both for paintings and works on paper.