What Is Foxing On Books? Top Full Answer 2022

What is foxing on books? Foxing on books is a type of book damage caused by a chemical reaction between the paper and the environment. The most common cause of foxing is exposure to high humidity levels, which causes the paper to become discolored and spotted. Foxing can also be caused by exposure to pollutants in the air, such as smoke or mold.

What Is Foxing On Books?

What Is Foxing
what is foxing on books?

Foxing refers to disfiguring little yellow-brown patches or defects in your newspaper. Iron and mold pollutants from the newspaper are two major culprits. Molds feed the newspaper, as do any filth or organic material, such as fingerprints, food stains, and smashed insects.

Tiny metal impurities are present in newspapers due to the manufacturing process or as a result of filth and pollution. Damp environments encourage mold development and cause iron impurities to rust.

A conservator may be able to reduce the disfiguring impact of foxing in certain circumstances, but in many cases, you must accept this earlier injury.

Recently released books are expected to be short-lived nowadays, and how we utilize them reflects this. People commonly push open the pages of a new paperback and press firmly on the spine’s inside to keep the book open.

This is often accompanied by a shattering sound when the acute fractures form. Although this is appropriate for a one-time bestseller, you must exercise caution if you want to pass on your works to future generations.

First, determine if your newspaper and books have historical, artistic, or emotional worth. If you feel they are valuable, consider having them appraised, guaranteed, and carefully preserved.

The cost of inattention and poor-quality repairs is high. Because books aren’t often displayed as attractive things in their own right, there’s sometimes a reluctance to pay for competent conservation. It would help if you weighed this against your books’ monetary and emotional worth.

How to Prevent and Reverse Foxing in Rare Books

How to Prevent and Reverse Foxing in Rare Books

There is never a bad moment to think about the effects of humidity and moisture on rare books. Too much sunshine, like too much smoke, may be harmful to your precious books. And we’re not talking about direct water, such as spilled liquids.

The relative humidity of the air might be a problem. Extra humidity (usually relative humidity over 75%) may encourage the development of fungus and mold, leading to foxing. What are the most efficient ways to reverse foxing if it occurs? Even better, how do you keep your valuable books from foxing?

Tips to Prevent Foxing

The greatest way to avoid continued or initial foxing in your rare books is to store them correctly. Readers should be stored in a safe, dry place. Libraries and museums maintain a relative humidity of 50%, eliminating foxing. Use the following approaches at home:

Completely store your books. Please store them in a location with central air conditioning and heating. Digital devices are trustworthy and reasonably priced.

If you reside in a comparatively humid region, consider using a dehumidifier.

Always use acid-free paper when wrapping, mailing, or mounting rare books and ephemera. Foxing changes the pH of this newspaper, and more acid may cause further destruction.

Strategies to Remove Foxing

Typically, removing foxing markings must be left to a skilled book conservator or preservationist. Professionals might choose between two methods for undoing foxing:

In the newspaper, they use a reducing agent such as sodium borohydride. These representations are mild enough not to need to be removed from the newspaper after treatment, but they may not remove the markings.

They’re repairing the newspaper using an oxidizing chemical like sodium tetraborate. Oxidizing chemicals, which are more strong than reducing agents, must be removed from the newspaper after treatment.

The effectiveness of this broker is determined by the weight of this book’s document. As a result, the chemicals must be properly mixed and applied. Most rare book vendors will choose to leave foxing alone and try to prevent further damage.

Additionally, look for signs that foxing was removed with bleach since this may cause the newspaper to decay quickly. Page wrinkling and edema may result during bleach treatment.

The definition and fundamental chemistry of foxing stains on books, papers, and images

It’s worth noting that the word “foxing,” which refers to brown or reddish-brown discoloration on books, papers, and certain pictures, is derived from The F and Ox in Ferrous Oxide, or iron oxide deposits that are attracted to places in the paper substrate.

The essential or gating component in the formation of foxing stains is the prolonged exposure of a book or other paper materials to water or, more often, excessive humidity.

This similar humidity exposure plays a role in the development of fungal growth in or on books and papers and other materials such as book bindings, glues, cloth covers, and, of course, other interior construction materials and surfaces.

What Do Foxing Stains Look Like on Books or Paper?

What Do Foxing Stains Look Like on Books or Paper

I’m not a book or paper conservator, but our picture (above left) shows an example of minor foxing markings or stains on both the page edges and inside the pages. The illustration is from our copy of Dora Russell’s Hypatia or Woman and Knowledge, third impression, produced by Mackays Ltd., Chatam, London, in the mid-1920s.

We see a characteristic fungal colony pattern when we examine little brown patches of “foxing” stains on a sample sheet macroscopically. The colony grew from a single spore core.

However, light microscopy of these samples in acid fuchsin and KOH (not the best mountant chemicals for this purpose) and dry without a cover slide and using both reflected and transmitted light produced just a few fungal spores resembling Cladosporium sphaerospermum.

Our picture on the left shows the preparation of a big sample (triangular cut) of one of these dark spots.

More research is being conducted, and other specialists have analyzed foxing stains using different approaches, including FLIR. [Forensic microscopic photos of these stain ingredients will be available soon. [Ed.]

Research reported by Arai et al. s. Established the fungal basis of foxing stains. Recently, Zotti et al, discovered Cladosporium sphaerospermum, Penicillium purpurogenum, Aspergillus malleus, Pithomyces chartarum, and Aspergillus sclerotiorum as among the most prevalent fungus linked with foxing markings or stains on paper using FLIR, culturing, and other approaches. The researchers discovered these fungal genera/species before and after microwave treatment of foxed papers.

Further research by the same authors discovered that these biotas were missing after mechanical “rubbing” of the stained regions to remove the visible stain, which astonished me.

My early research on brown foxing stains like the ones illustrated above shows that the foxing stains contain components that lie inside the matrix of wood pulp fibers that comprise the paper itself, making mechanical surface treatments challenging.

While fungi and certain yeasts are identified in foxing markings on books and papers, the main genera and species seem to be in the Penicillium group, according to Zotti, who has done considerable study on foxing alongside Arai.

There were ten species of filamentous fungus and one yeast type discovered. Penicillium was the most often represented fungal species, with five distinct strains, whereas each of the other genera had just one species.


How do you get rid of foxing in a book?

Generally, removing foxing markings should be left to a qualified book conservator or preservationist. Experts can reverse fox using one of two methods: On the paper, use a reducing agent such as sodium borohydride.

Does foxing on books spread?

Foxing is a natural aging process that causes reddish-brown stains and stains on old newspapers. Unlike mold, foxing spreads evenly across online pages and cannot spread to other books or items.

Is book foxing mold?

Foxing is caused by mold and metal impurities in paper. Foxing occurs on brown, yellow, or red stains on paper, frequently in spidery patches or scars.

Can foxing be removed?

How Do You Get Foxing Stains Out of Paper? Foxing stains may be cleaned using chlorine bleach or normal home bleach (Sodium Hypochlorite), which has high alkalinity and readily destroys paper fibers.

What causes brown spots on old books?

Foxing. The word ‘foxing’ refers to the appearance of little golden brown patches or blotches on paper. Mold and iron impurities in the paper are the two most common reasons. Molds feed on both the paper and any dirt or organic material, such as fingerprints, food stains, and crushed insects.


Foxing is a common problem for books. It is caused by a reaction between the paper and the environment, usually involving moisture and fungi. The result is brown or reddish spots on the paper. While foxing does not usually damage the paper itself, it can make the book difficult to read.