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    Tips of the Trade

    Verifying Antique Maps


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    Don't be fooled by a modern reproduction of an antique map.

    A loupe is the most important tool for the hunter of old maps.

    Creases are a sign of authenticity in old maps.

    Paper made before 1800 almost always looks different.

    An avid map-lover pokes around a flea market to see if she can find an antique map of the United States. She flips through a bunch of old-looking maps in a crumbling cardboard boxes and finds one, dated 1784, that depicts the United States as far west as the Mississippi River. The 13 original colonies on the eastern seaboard—the only ones that were part of the country at that time—are distinguished with soft pastel colors. The woman is entranced by the map, which is wrapped in plastic. She sees the $50 price tag stuck to it.

    Don't be fooled by a reproduction "antique" map

    "Is this an antique map," she asks the owner of the booth, who is chewing on a toothpick. "Or is it one of those 20th-century photo-mechanical reproductions?"

    "It doesn't look like a photo to me," the guy replies. "But if you're really interested, I'll sell it to you for $40."

    She's hardly convinced. Is there a way she might tell if she's looking at an antique treasure of a map, or one of the millions of photo-reproductions produced over the last 100 years? Chris Lane, co-owner of the Philadelphia Print Shop, says there are ways our hypothetical collector—and you—can learn a few tricks to identify antique maps from their copies.

    Distinguishing the two kinds of maps is crucial, because only antique maps have the historical and monetary value that map copies largely lack.

    "Antique maps are part of history," Chris says. "They were made at a particular point in time, when people used them and they had an influence on the course of events. Modern maps are mere copies with decorative value only, like a poster."

    Zooming In
    When Chris leaves his shop looking for an antique map, he always goes hunting armed with an 8X-power magnifying loop. By looking at a map through his pocket-sized magnifying lens he can see one of the tell-tale signs of a photo-reproduction: a matrix of little dots that make up the image.

    "The loop is a crucial tool," Chris says. "I never go anywhere without it." The extra magnification is especially helpful in detecting the modern photo-mechanical maps that are obscured behind glass or plastic.

    Folds and Plate Marks
    Another signal that a map is an original antique, instead of a modern reproduction, is a fold down the center of the map. Most of the antique maps that have survived until today were produced for atlases. Any map bigger than a standard sheet of paper would probably have straddled two pages in its atlas; thus it would have a fold down the middle so as to fit into the atlas when closed. Whereas maps manufactured in the 20th century were meant primarily to be mounted on a wall as decoration, and lack these folds.

    Most maps made before the middle of the 19th century were copper engravings. This process creates a little ridge, called a plate mark, around the edge of the map—a result of the plate's pressing against the paper. While wood cuts and lithographs do not have plate marks, the absence of a plate mark on a pre-1840 map should raise a red flag, because of the prevalence of copper engraving during that period.

    Maps Before 1800
    But if the map that our flea-market shopper found was made before 1800, as its 1784 date claims, it should also be printed on a different kind of paper.

    "Almost all maps made before 1800 used hand-laid paper," Chris says. This paper was made by hand rather than by machine, which came about later. It was made by pouring paper pulp into a wooden frame with a bottom of cross-hatched wire mesh, which would leave its pattern in the paper.

    "If you pick up a map and hold it up to the light you'll see a series of close-together thin lines crossed about every inch or so by a perpendicular line," Chris says. "Those are called chain marks. It looks a little like the weave of a rug." Later papers made in the 19th century by machine don't have these cross-hatches.

    Chris adds that all reputable antique map dealers make a practice of culling out the real antique maps from the reproductions, which makes them the safest places to buy antique maps. Auctions can be a different story altogether. "I once saw a reproduction sold at Sotheby's," he says.

    For more information on collecting antique maps, Chris recommends:
    A Guide to Collecting Antique Maps, by Christopher W. Lane with D.H. Cresswell, Philadelphia Print Shop, 1997.
    Collecting Antique Maps, by Jonathan Potter, London, 1999.
    Antique Maps: A Collector's Handbook, by David Bannister and Carl Moreland

    More ANTIQUES ROADSHOW Tips from the Prints & Posters category:
    Finding a One-of-a-Kind Map (Tucson, 2007)
    WPA: Putting Art to Work (Houston, 2006)
    Chromolithography: Bringing Color to the Masses
    Jules Chéret: Elevating Ads to an Art Form (St. Paul, 2005)
    Who Were the Prairie Print Makers? (Portland, 2005)
    Lithography 101
    World War One Posters: Easy Targets

    Dennis Gaffney is a freelance writer in Albany, New York. He has been a regular contributor to ANTIQUES ROADSHOW Online since 1998.