Old Map plates, Globe Gores & Ephemera

Most of the paper is made from wood which consists of cellulose and lignin. These components are high oxidizing agents and hence turn to yellow when exposed to oxygen over time. Indeed, your books dislike sunlight. The UV rays present in the light prompt and encourage the action of the oxidation process.

Foxing is an age-related process of deterioration that causes spots and browning on old paper documents such as books, postage stamps, old paper money and certificates. The name may derive from the fox-like reddish-brown colour of the stains, caused by the rust chemical ferric oxide which may be involved. Paper so affected is said to be "foxed".

Foxing is rarely found in incunabula, or books printed before 1501. Decrease in rag fibre quality may be a culprit; as demand for paper rose in later centuries, papermakers used less water and spent less time cleansing the rag fibres used to make paper. An early work of art to have been affected by foxing is the Portrait of a Man in Red Chalk, a drawing on paper by Leonardo da Vinci.

The causes of foxing are not well understood. One theory is that foxing is caused by a fungal growth on the paper. Another theory is that foxing is caused by the effect on certain papers of the oxidation of iron, copper, or other substances in the pulp or rag from which the paper was made. It is possible that multiple factors are involved. High humidity may contribute to foxing. Foxed documents can be repaired, with greater or lesser success, using sodium borohydride, proprietary bleaches, dilute hydrogen peroxide or lasers. Each method risks side effects or damage to the paper or ink.

Another method is to scan the image and process that image using a high-level image processing program. This can usually remove the effects of foxing while leaving text and images intact.– (Courtesy of Wikipedia).

Old globes Can yellow and darken with age. This is caused by acids in the wood and papers used to create the globe and/or the layered varnish or shellac that was applied over the paper surface of many globes. In some instances, this discolouration can be remedied or reduced by cautiously cleaning. The map gores can very easily and irreparably be damaged by incorrect cleaning. Using specialist conservators who have the right museum grade materials and experience is recommended.

Ultraviolet light can fade the maps, darken and yellow any surface varnish that may have been applied over the maps and cause parting and separation of the globes support orb and gores. It is recommended that UV protective glass is applied during framing and positioning the map or globe in a conspicuous place away from sunlight advisable.

HiBCoR - Map Grading System

Grading systems can be subjective and therefore varies between the types of maps graded along with their age and condition to a certain extent.

The HiBCoR grading system with condition codes were introduced by Graham Arader in 1979. Others like Rodney Shirley used a Rarity Index system that has also been popular among cartographic dealers & collectors.

The HiBCoR system uses four main areas for consideration -  Historical importance, Beauty, Condition and Rarity. This grading type is on a scale of 1 to 10.

Rarer maps in poorer condition may be graded higher than a more common map in good condition. Price is always a condition of grading with a rare map showing more colour originality and vibrancy, gaining favour over a modern map with similar attributes.

Prices can be significantly different. I tend to research Maps and Globes that are for sale on the open market, reading their descriptors and deciding where my product reasonably sits in between, in a fair and consistent way. Beware, as many antiques can be marketed and priced far higher than they should be, often by sellers who have no knowledge of the product and often surreptitiously disregarding significant damage that may be present.  

Maps and globes, particularly old ones that have highly decorate cartouches, borders, monsters and sea creatures, ships, compass roses and scrollwork may command more of a decorative premium.

The older the map or globe may determine the type of surface product used. Handmade paper, velum or laid parchment that was used in period times. Printing processes like Rock Petroglyphs, Woodblock, Copper Plate, Steel Plate, Line Engraving, Lithography, Intaglio, Raised Relief, Etching, Mezzotint, are all different modes of creation. Engravers used tools called a Burin or Graver to cut designs into surfaces of the printing plates before an engraving was pressed. Copper was traditionally used as a printing plate surface and then steel in more modern times.

Cartographic materials were expensive in period times, and it often took time to create the paper and many months to produce large scale detailed engravings. Maps of period drawings and sketches of far reached areas of the world would often be engraved many months after their conceptional design, because of the time and distance taken before the traveller returned home. Atlases that encompassed many maps took even longer to construct.

I use a slightly different (A+ to C) grading process that encompasses the salient points within HiBCoR. This is detailed in my Terms and Conditions page.