What’s Foxing?

Print anything with Printful



Foxing is rusty brown color defects found on paper from the 18th and 19th centuries. The cause is unknown, but it’s believed to be related to fungi and iron salts. Controlling humidity can manage foxing, but restoration methods are debated and can damage paper quality. Some people attempt to remove fox stains to maintain or increase the value of items such as old books or artwork.

Foxing is a term that refers to rusty brown color defects on paper. The condition is commonly found on items produced in the 18th and 19th centuries. The exact cause of foxing is not known, and methods of recovering foxing are debated. It is believed that the problem is best managed by controlling humidity and contact.
A person may find that vintage paper, including that used for documents, artwork, and maps, is prone to developing fox spots. When this happens, the object is said to be fox. Why these spots appear and the cause of these spots are not conclusive.

Speculation, however, attributes the problem to interactions between fungi and iron salts, or ferrous oxide, in the paper. Mushroom spores are small and can easily travel through the air. Foxing often starts at the edges of pages and moves inward. For many, this suggests that environmental factors indeed play a significant role in the problem. It is also believed that acidic materials, such as cardboard and glues that come into contact with an object, can aggravate foxing.

The condition can generally be controlled if the relative humidity is controlled. A certain degree of relative humidity is required for mushroom growth. Therefore, it is recommended that you store items that have faded or may become faded in a location where the relative humidity is below 70 percent. When this happens, the mushrooms should go dormant. It should be noted, however, that if the document is taken out of this controlled environment, the fungi are likely to start growing again.

There are several ways to reset foxing. The effects of the spots can be reduced with sodium borohydride or calcium hypochlorite. Some people have found that repeatedly dabbing hydrogen peroxide on stains gets rid of them. The debate about restoring foxing arises from the problems that can be associated with each method. Attempting to fix fox spots often damages paper quality, compromises artwork or printed content, or works only in the short term causing more problems in the long run.

As there is debate regarding the restoration of foxing, there are also debates about the need for such a process. Many people attempt to remove fox stains to maintain or increase the value of items such as old books or artwork. Some, however, feel that like other antiques, defects should not be a factor that detracts from value.




Protect your devices with Threat Protection by NordVPN


Skip to content