How to Preserve Antique Maps

“Maps are a universal medium for communication, easily understood and appreciated by most people, regardless of language or culture,” said revered American geologist Daniel F. Merriam.

Throughout the history of humanity people have been going to or coming from some place. It’s a shared experience, if not physically, certainly intellectually. In some cases, that shared experience has contributed to maps. Most often today, it’s a digital map of some type that guides people in their travels. However, not so long ago printed maps were a daily part of life, and a folded paper map could be found in the glove compartment of nearly every vehicle on the road. Schoolchildren could expect to see a map of the world in their classrooms.

Today, antique and vintage maps are objects appreciated by collectors, historians, artists and academics, among others. To learn the ins and outs of collecting maps, see the archived article Collecting Old Maps, featuring expertise from Jasper52’s resident map expert Steve Kovacs.

Once again we turn to Steve for insight on the correct way to conserve old maps so they can remain intact and beautiful for future generations to enjoy.

Does the type of materials the map is printed on make a difference in whether or how quickly a map may deteriorate? Is it true some of the earlier maps, made of a paper with a fiber core, fare better over time than some made from more modern elements? 

The nature and quality of the paper substrate (n.b. – underlying layer of material) on which the map is printed are among the most important factors impacting the long-term condition of the map. Interestingly, older maps, primarily pre-1800, are more likely to maintain their condition, given that they were usually made of linen rags or flax with longer fibers and were low in acid-producing lignin content. With the ever-growing demand for paper to make maps, books and newspapers, by the early to mid-1800s the industry increasingly turned to a much cheaper paper source, wood pulp. Wood-based paper unfortunately has shorter fibers and much more lignin, which is a natural part of the wood structure. In turn, lignin will give off organic acids upon exposure to air and light, and these acids cause yellowing, browning and brittleness to the paper over time.

What are some of the most common issues impacting the condition of a map, and what are some specific steps one can take to avoid each?

As with paper in general, moist or wet conditions, large temperature fluctuations, UV light, oxygen in the air, and pests (worms, insects, rodents) can all contribute to the degradation of the paper itself or the pigment or dye in colored maps. Aside from handling abuses or crayon or ink markings, most condition issues are caused by these environmental factors. Moisture in combination with higher temperatures often causes mildew to develop. UV light and oxygen can cause foxing (reddish-brown spots), yellowing, browning and brittleness, especially in paper made of wood pulp, and degrade some pigments and dyes, thus changing or fading the colors.

To mitigate these potential issues, some common-sense steps in storage or display should be exercised, as outlined in the next section. Also, if the map is dear to you, consider cleaning and professional de-acidification – a simple washing process – to minimize any further yellowing, browning or brittleness that might otherwise occur.

View a presentation of conservation techniques involving the treatment of an 1808 map of Milledgeville, Georgia. Note: The video is visual only; no sound:

What are some options for storing maps properly and safely?

Maps should be kept in typical room-temperature and humidity conditions, so not in hot attics, not in damp basements, and not next to heat sources. Preferably keep the maps laid flat in boxes or shallow drawers and, less ideally, gently rolled in a tube that is at least three inches in diameter. Very importantly, longer-term direct physical contact with the map should be only by archival, acid-free materials, an excellent option among these being polyester (e.g., Mylar) sleeves or acid-free paper. Avoid direct sun exposure and handling with dirty hands.

How would you recommend someone display an antique map, if that is their intention, so it isn’t compromised by light and moisture?

Many of us elect to display some of our favorite maps, and usually in frames. Before framing, it’s best to restore the map if there are any defects. As noted earlier, all physical contact with the map should be with archival, acid-free material, including the matting, the support board behind the map, etc. Do not glue the map to a board or backing; rather, use mounting corners or possibly acid-free hinging tapes to hold the map in place. If the map is fragile, backing with Japanese paper might be warranted. Avoid direct contact between map and glass. UV glass should be used, and do keep the framed map away from direct sunlight and heat sources. A professional framer who is familiar with maps should be considered.

What are some signs that a map is damaged? Some are more obvious than others I suspect, so how can you tell?

Most damage is readily visible on a map: 1) discoloration due to mildew, soiling, foxing, yellowing, browning, color fading; 2) voids caused by pests or mishandling, 3) tears, splits; 4) water stains, 5) uneven surfaces, etc. Needless to say, both sides should be evaluated. Brittleness is often not visible but can be devastating to a map.

If a map is damaged is finding a conservator the best next step? What kind of things should one look for or check on to determine the conservator you are looking to work with is reputable?

Nothing lasts forever, but if a map is damaged, short of a minor issue (unclean surface, small tear, slight and age appropriate discoloration), it is typically best to engage a professional conservator or restoration expert, or your map might suffer considerably over time. Cleaning dirt off the surface, closing a small tear with archival material on the back or minor flattening under weights are about as far most of us ought to take do it yourself conservation, and only if one is confident doing so after reading how to perform the task properly.

The process of finding a conservator or restoration expert is like finding any other good professional. Most people would rely on information such as: a) personal recommendations by trusted antique map or book dealers or fellow map collectors; b) inquiring about length of time in the conservation and restoration business; c) learning about their experience base suggested by their client list (see if they have serviced antique map and book dealers and institutions) and viewing before-and-after restoration images of items; d) considering their professional accreditations (i.e., AIC – American Institute of Conservation) and the like.

While having the conservator nearby is good, shipping to a conservator is a good option as well. Do get an estimate up front, though (pictures of the problems to be resolved do help), as restoration service pricing can vary significantly. There are numerous individuals or companies offering restoration and conservation of works on paper – maps, books, letters, paintings – and some also deal with other forms, such as paintings on canvas, photographs, etc.

What are your four best pieces of advice when it comes to preserving and caring for an antique map?

When it comes to preservation and care of maps I’d offer the following thoughts:

• Enjoy your maps. Chances are, most of them are many multiples of your age and have survived. But don’t add stress to their lives through abuse or neglect. Be knowledgeable what heals them and what prolongs their lives.    
• The most important and likely easiest step is to help mitigate any future deterioration through appropriately storing or displaying your maps, as was discussed earlier.
• Decide what role each map plays in your life. Is it dear to your heart? Will you or do you already prominently display it? Will you keep it in your collection long term? Or, is it just a nice-to-have map? The more important the map is to you, the more important it is that you proactively consider any restoration that might be needed.   
• When it comes to active conservation and restoration, aside from minor steps, it is typically best to use the services of a professional conservator or restoration expert. With that said, balance the cost of restoration with the monetary and sentimental value of the map.

If you are looking for a new subject on which to focus your collecting efforts, you might want to consider antique and vintage maps, which are a fusion of several interests in one fascinating topic.

About the Expert:

Steve Kovacs has been passionate about geography and maps for five decades. His interest has taken him from studying and collecting maps to opening a boutique online map gallery. He also enjoys putting his knowledge of maps to use for his global travels – he’s visited 55 countries so far. He also has a background in science, engineering and business. He is a member of the International Map Collectors’ Society and serves as the expert curating Map auctions for Jasper52.