Prior to the mid 1800’s most maps were printed on paper handmade from plant fibres usually derived from old linen and cotton rags, hence the term “rag paper”. By around 1850 machine-made paper became dominant and most maps were printed on this paper. While this change made the production of maps cheaper the disadvantage was that machine-made paper included wood pulp which contained lignin and was acidic. Over time this causes the paper to become fragile as the acid attacks the fibres and the paper becomes brittle and inflexible resulting in tears and paper loss. A classic sign that paper contains wood pulp is it begins to turn brown, the rate of which increases with exposure to light.
A solution for the preserving and strengthening maps is to lay them down on linen or cotton cloth. This method of strengthening maps has been used for centuries, especially on folding maps or those subjected to a lot of handling. It is also used on items that were printed on cheap paper, such as film posters, that were never intended to last for years, many of which are now in a very delicate condition.
If the map is intended to be framed, then we can lay it down in one piece rather than dissecting it. The reason for dissection is that it can be folded without damage to the map and a slipcase made that protects and keeps the map out of the light.
Should you have a map, or indeed any other paper item such as a poster, that is torn or damaged in one way or another and you think is beyond repair, send us an email, preferably with a photo. We may well be able to save it, even if it has a piece missing it will still have a value though it may be only sentimental.
We only repair the physical damage to paper to prevent the item crumbling or falling apart. Other problems, such as foxing or mould, should be treated by a trained conservator.
Foxing is quite a common condition in old maps or prints. It manifests itself in reddish brown spots and is so named because of the similarity in colour to the fox. Although badly foxed paper can be unsightly the structure of the paper is not damaged and if the item is kept away from humidity and bright light it should not increase.
Experts do not fully agree about the causes of foxing but it probably involves humidity, fungal spores and compounds such as copper and iron in the paper.
The treatment of foxing and other conditions is best left to a professional paper restorer, more especially if the item is valuable. The use of bleaching agents as sometimes advocated online is not advisable. The treatment usually involves chemicals that can further damage the paper. If the foxing does not bother you it is best left alone.