Antique maps present an interesting problem for the amateur collector: how does one distinguish a true antique from a reproduction? The world abounds with ephemera (paper goods) relating to geography, some of which has been mass-produced for anniversaries of world events or convening of countries or border changes; however, there are some signs of age that anyone can detect.
One simple thing anyone can do to education themselves about ephemera is to visit your local librarys rare book room or an antiquarian bookseller. Ask to see any map or botanical illustration books they may have, and specify that you are interested in those with hand-colored plates. Examine the impressions in the paper made by stone lithography. This way you can get a feel for what old paper with watercolor brushstrokes on it looks like. You could also search online for antique maps to get a feel for coloring and age of antique examples, but of course, observing antique ephemera in person is the best way to learn.
One English example we have consigned is a map of Cambridge, but the subject itself is not what is important about this item. The map is signed Christophorus Saxton at the lower right (most important maps list a cartographer near the directional compass or in an informational sidebar somewhere on the map). Saxton was the first cartographer to make a survey of England and Wales in 1570. Seven years later, the first atlas of the country was published, and which was continually published until the late 18th century. The Cambridge map is likely an example from that book, but I could not find another copy online to compare it with. The version we have is on very old paper with printing at the reverse and there is watercolor and gouache highlighting as part of the design of the map. Since the printing is spotty and the hand coloring in not entirely artful, I estimate this example to sell for $100 to $200 at auction.
Another framed map we have for auction is Dutch cartographer Willem Blaeus map of the Elbe River, including the Port of Hamburg, circa 1634. This map is from the French edition of his atlas entitled Theatrum, and is definitely taken from a book (the pages have a seam down the middle). This example does not have as much coloring as other examples I have seen, but it would be an interesting curiosity for someone how loves German culture. Due, to its pale coloration and fading, I would estimate it to sell for $75 to $150.
An unusual case is a map of Italy by Nicholas Visscher, who was part of a Dutch mapmaking dynasty that persisted until the early 18th century, when the plates were sold for preproduction to a printmaker. The example we have is likely a late 18th century copy from a book, indicated by the lack of coloration to the etchings figural decorations, which depict allegorical water nymphs and putti around the title boxes (putti is the plural form for the plump cherubs with wings that can often be seen in Renaissance, Mannerist, Baroque and Rococo art). Very valuable copies seem to have very fine polychrome watercolor work, and this example does not. I estimate this map to sell in the $100 to $400 range.
If you are interested in further information on antique maps you might want to explore the following references: