Excerpt from the Journal of Advanced Appraisal Studies

Fellow Washington DC area appraiser and auction specialist Dale Sorenson, Ph.D. of Waverly Auctions wrote a very good introduction to inspecting and appraising maps.

Dale Sorenson, Ph.D., has had 30 years experience appraising and selling at auction rare and used maps and atlases, books, prints, autographs and manuscripts. 27 of those years were spent by him owning and develop-ing Waverly Auctions into an international market place of those items listed above. Four years ago he sold Waverly Auctions to Quinn's Auctions in Falls Church, Virginia, where he is currently employed as Director of Waverly Auctions.

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From the Journal of Advanced Appraisal Studies, A Primer on Valuating and Appraising Maps, by Dale Sorenson, Ph.D.


An accurate dating of a map requires more than accepting the date (if there is one) in the cartouche. The copper plates used to print maps were often reworked by a new publisher/mapmaker to reflect changes in geography, patronage, cartographer, or publisher. This later issue or printing by the new publisher might not include a date or the original date might be left intact. Many maps were produced to become part of an atlas. One atlas by Ortelius, Theatrum Orbis Terrarum, was first published in 1570 in Latin (text showing on the verso of the map). He died in 1598, but his atlas continued to be published until 1624; by that time at least 42 editions had been published in Latin, French, Spanish, Italian, and German. The date on a map might remain for several years before it was changed. If the text is present on the verso, a review of map references (several are mentioned at the end of this article) might point to a few dates as best options. Of the 42 editions noted above, at least 22 were published from 1570 - 1624 with a Latin text on the verso. If the precise dating proved impossible, then one could use that date range instead. If the text on the verso was in Spanish, the date range would narrow - the first atlas published in Spanish was 1588, the last in 1612. Size might also be a factor here; the same maps for the folio size were reduced in size and published in 31 editions between 1576 and 1697. Ordinarily each map of the smaller size would have less value than its larger folio size map. See pages 29-30 of Tooley, Maps & Map-Makers, cited in References.

When recording a date or date range, it is an acceptable practice to put within brackets a date found in a reference book or a date arrived at after further research. If a date can be found on the map but research leads to the conclusion that the map was actually printed later, it is acceptable practice to include the recorded date followed by the actual date within brackets. Or, one might only be able to conclude and state that a map was printed about a certain date (circa), or after a certain date.

Maps were not printed in color until the 19th century, when litho-graphy became prominent. Many of the early maps were hand-colored in outline only, largely to define some geographic aspect, such as mountains, bodies of water, political borders. The traditional colors used were blue (water), green (countryside), brown and red (mountains), etc. Cartouches were often left plain probably because they required more skill to apply the color. It isn’t easy to determine early from later color, but one can be reasonably assured of early color by holding the map up to the light (where chain lines and watermarks can also be seen). If the coloring bleeds through to the back (especially green which had copper in the mixture), it is probably contemporary color (meaning of or near the time the map was produced). One might find the cartouche colored as well, but often that will have been added later. These observations are quite general and there are exceptions. So, each map needs to be viewed (literally) separately from any strict guidelines. If the coloring is well-executed, the value of the map is normally enhanced, and especially if the coloring is early or contemporary. However, in the case of a wood block map, more often than not, early or later coloring detracts from its simplicity and thus reduces its commercial value. I am aware of a recent auction where a rare wood block map of North America went unsold because it had been hand-colored.