GLOSSARY OF MAP TERMS

Note: In the texts accompanying the maps on our webpage listings we use certain designated words and terms, explained below.

1. Age-toning. A descriptive word for areas of discoloration or browning that have appeared on old maps over the years. Generally from improper storage and handling.

2. Blue-Back chart. A method used by private publishers in London during the 19th century to distinguish them from the official Admiralty charts. The name came from the heavy blue paper backing used by publishers to strengthen the charts. The blue-backing was also used by American chartmakers Edmund Blunt and George Eldridge in the late 19th/early 20th century.

3. Cartouche. An ornate or ornamental frame drawn by engravers on old maps as decorative surrounds for map titles or information which often included the name of the cartographer and the date and location of the publisher or printer.

4. Chain & Wire marks. These are crossed lines, often visible on handmade rag paper when held to the light that came from the impression of the grid on which the rag pulp was spread to dry during the early paper-making process.

5. Circa (c). The word Circa and its symbol (c.) means approximate. When dating old maps sometimes the precise date of issue is not known so an approximate date e.g. c.1759 is used to define a period of time when the cartographer flourished and was known to have worked on similar maps.

6. Compass Rose. The design from a compass card, engraved on a chart for navigators to set their bearings on a pre-selected course and by which bearings of visible objects may be taken to fix a ship's position on a chart.

7. Copper engraving. The method of engraving & printing maps from copper plates and used by engravers from the 16thcentury until the early 19thcentury. About 800-1000 'pulls' or images could be taken from the plate before it needed to be re-etched.

8. Lithography. A method of printing, popular in the 19th century where the image was cut on a stone or other substance and inked in selected areas that are chemically treated, and transferred to paper.

9. Meridian. From the Latin 'medius' meaning middle and 'dies' meaing day. A semi great circle joining the earth's poles known as lines of Longitude crossing the equator and all parallels of Latitude at right angles.

10. Neat Line. This is an engraved line that is drawn around the perimeter of the map's image.

11. Octavo. A paper size approximately 8"X9". Bound into a book it is folded in half three times. Abbreviation 8vo.

12. Outline Color. Hand color that is applied to old maps only around the land boundaries and the seacoast.

13. Platemark. A slightly raised border around a map made by the impression of the copper or steel plate used in engraving a map or print.

14. Prime Meridian. In 1880 international agreement was reached to accept the longitude of Greenwich, England as the Prime Meridian from which all sea time is measured. Prior to that England, Spain and France had their own Meridians through the Azores, Paris and London. Some early sea charts included all three Meridians on their surface.

15. Quarto. A sheet of paper folded in half twice with dimensions approximately 9"X11". Abbreviation: 4to.

16. Recto and Verso. Recto is the front side of a page. Verso is the reverse.

17. Re-margined. A map that has had a margin added or extended generally to add space for matting when framing. Maps published in atlases sometimes had narrow margins along the bound edges and sometimes when maps were issed two or three to a page, they have been cut into individual images requiring margins to be added on two or three sides.

18. Rhumb Lines. Lines on the earth's surface which intersect all Meridians at the same angle. Meridians and parallels of Latitude are rhumb lines. Rhumb lines which cut Meridians at oblique angles are called Loxodromic curves. The radial lines on a compass are also called rhumbs. On early charts rhumb lines are drawn radiating out from a compass rose.

19. Rococo. An 18th century French style of ornamentation that included leaf, flower, shell and scroll motifs, often used as frames or cartouches surrounding the title on 18th century maps. A style much used by Jacques Nicolas Bellin, Hydrographer to the King in Paris in the 18th century to decorate his maps and charts.

20. Steel Engraving. A method of engraving and printing from steel plates which became popular in the mid 19th century. As steel was a much harder substance than copper, many more images could be printed from the plate before it needed to be re-etched.

21. Wood Cuts. A method of printing from a wooden block on which an image is cut in reverse. Primarily used to the middle 1500's before copperplate printing became popular.

References:

“The Makers of the Blue Back Chart” by Susanna Fisher
“The Oxford Companion to Ships and the Sea” Ed. Peter Kemp.
“How to Identify Prints” by Bamber Gasgoigne.

Conservation and Care of Old Maps, Prints and Paintings.