Foxing Stains on Books, Papers, Photographs: cause, cures, prevention

FOXING STAINS on books & papers - Definition of Foxing Stains on Books, Papers, Photographs: cause, cure, prevention
ARTWORK MOLD CONTAMINATION - separate article
BOOK MOLD, Moldy Book Cleaning - separate article
Questions & Answers about the cause, cure, & prevention of reddish-brown foxing stains on books, papers, photographs & similar materials
References

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Foxing stains: this article defines book & paper foxing - those reddish-brown stains found on some old books, papers, photographs, and other paper products. We explain the causes of foxing stains, the chemistry and mold components of foxing, and we describe what foxing looks like, how it is cleaned from books, papers, or photographs, and how foxing can best be prevented by book and paper restorers and paper conservators. We provide and cite an extensive list of authoritative references about foxing: cause, cure, and prevention. Also see BOOK MOLD, Moldy Book Cleaning.

Foxing Stains on Books, Papers, Photographs: cause, cure, prevention

Question/Comment: what causes rusty stains or foxing marks on books and paper ? Foxing definition, chemistry, causes, treatments or removal methods, and prevention

Are foxing marks on books and paper always caused by mould or are other factors also at work?

Also, I have a couple of books with shiny pages that have become sticky during a humid summer and have developed orange lines along the edges of some of the pages.

Is this a reaction of the acid in the books seeping through the cut edges or could mould be a factor? - Rachel 9/2/202

At left our photograph of book foxing illustrates foxing stains on the page edges of the book discussed in this article. Photograph taken in direct sunlight.

Reply: iron oxide, fungi and yeast associated with foxing on books and papers: causes, cures, prevention

Rachel,

Your surmise that more than mold is at work in the development of local discoloration or reddish-brown foxing marks on paper and books is correct in that at the core, foxing is caused by exposure of those materials to high humidity, and the brown stains characteristic of foxing marks are typically found to contain high levels of iron oxide (FeO) in one or more chemical forms. Paper chemistry as well as chemistry of inks and other materials comprising the book, paper, stamp, or other foxed document are also important components in the foxing problem. (Carter explains that the general yellowing of some paper products is distinct from the localized red-brown stains associated with foxing. [36][37])

How experts examine foxing stains on paper products

Foxing and other stains on paper are typically examined by several methods including

Direct visual examination in daylight or under daylight-frequency artificial light (photos included in this article) At left our photograph illustrates extensive foxing stains on the right-hand paper just inside the cover of the book used for these foxing illustrations. The role of chemistry of glues and other materials in the selective appearance of foxing stains in books and on other papers might be inferred by the foxing stain pattern shown at the right side of our photo.
Microscopic examination using transmitted light microscopy (photos included in this article)
Fluorescence, detected by exposure to UV radiation (“Wood light” instrument: Vilber Loumart, VL-15L, 15W–365 nm, tube power 30W). The procedure adopted follows the protocol presented in Zotti et al (2008)). [17a]
Light spectroscopy, or Fourier Transform Infrared (spectroscopy) - (FT-IR or FTIR), a term applied to a variety of types of spectroscopy including optical spectroscopy, infrared spectroscopy (FTIR, FT-NIRS, FTIR spectroscopy) - cf Zotti 2008 [17a]
Culture media might be used to further study some fungal species collected from a surface but with the caveat that most fungi will not grow on culture media and those that do may appear morphologically quite different from their growth on other substances (see MOLD CULTURE TEST KIT VALIDITY)

Brown stains on various paper goods may also be found to contain conidia and hyphae of fungi, but keep in mind that many of the fungi commonly identified as growing on or in paper products (listed below) do not themselves produce darkly-pigmented fungal materials. Some experts add that bacteria play a role in paper deterioration [29] (and possibly foxing), and indeed, fungi and certain bacteria are about the only natural organisms in the environment capable of breaking down cellulose.

Our own forensic microscopy lab work as well as that of other experts confirms an interesting diagnostic observation: the color and appearance of stains (black, brown, white, etc) that we see macroscopically or with the naked eye can be quite different from the color and appearance of the staining materials (often fungi) when examined at high magnification under the light microscope. [16]

In any case, and for those rusty reddish-brown foxing stains on paper, it appears that both moisture and several species of mold are at work together, conspiring in the accumulation of iron oxide stains or foxing stains on paper, as we explain in more detail here. It also is likely that paper and ink chemistry, such as pre-existing levels of iron in the paper, inks, bindings, or other materials is important in the development of foxing stains.

Definition & basic chemistry of foxing stains on books, papers, photographs

It is useful to note that the term foxing, used to describe brown or reddish brown discoloration appearing on books, papers, some photographs, derives its name from The F and Ox in Ferrous Oxide, or iron oxide deposits that are attracted to areas in the paper substrate. Exposure of a book or other paper materials to water or more often high humidity over the materials' life is the key or gating factor in the development of foxing stains. This same exposure to humidity is also a determining factor in the development of fungal growth in or on books and papers as well as on other materials such as book bindings, glues, cloth covers, and of course on other indoor building materials and surfaces.

Biotic foxing on paper is indeed a widely-recognized book and paper conservation concern. [1][2][3][4][5][6][7][8]9][10][11][12][14] Yet according to at least some of those experts, the biotic or even chemical origin of these stains remains unclear.

What do foxing stains look like on books or paper?

I'm not an expert book or paper conservator, but our photo (above left) is indeed a typical example of modest foxing marks or stains on both the page edges and within pages as well. The example is from our copy of Hypatia or Woman and Knowledge, by Dora Russell, third impression, printed by Mackays Ltd., Chatam, London, in the mid 1920's.

Examining small brown spots of "foxing" stains from a sample page macroscopically we observe a classic fungal colony pattern - as if a colony has grown from a single spore center.

But examining these samples by light microscopy in acid fuchsin and in KOH (not the optimal mountant chemicals for this purpose) as well as dry without a cover slide and using reflected as well as transmitted light did not produce good images of fungal colonization, just a few fungal spores resembling Cladosporium sphaerospermum.

At left our photo illustrates preparing a large sample (triangular cut) of one of these brown stains.

Further work is in process, and of course other experts have examined foxing stains using other methods including FLIR. [16] [Forensic microscopic images of these stain materials are forthcoming. - Ed.]

Research reported by Arai et als established the fungal basis of foxing stains. [31][32][33][34] while more recently, Zotti et als, using FLIR, cultures, and other methods, identified Cladosporium sphaerospermum, Penicillium purpurogenum, Aspergillus melleus, Pithomyces chartarum, Aspergillus sclerotiorum as among the most common fungi associated with foxing marks or stains on paper. Those researchers found these fungal genera/species present before and after microwave treatment of foxed papers. [16]

Further work by the same authors found that these biota were absent after mechanical "rubbing" of the stained areas to remove the apparent stain - which surprised me. My own preliminary work on the brown foxing stains such as those shown here suggests that at least in some cases the foxing stains involve materials that reside within the matrix of wood pulp fibers comprising the paper itself, making successful mechanical surface treatments difficult.

In an earlier work the same lead author, Zotti, who along with Arai has done extensive research on foxing, noted that the while fungi and some yeasts are found in foxing marks on books and papers, the dominant genera and species appeared to be in the Penicillium group.

Ten species representative of filamentous fungi genera and one yeast form were identified. Of the fungal species, the one most frequently represented was Penicillium, with 5 different strains, while for each of the other genera there was only one species. [17]

What are the Foxing Fungi? fungi identified as growing on or in paper materials included the following

At least ten species of fungi and one yeast have been identified as growing on/in or "hosted by" paper, [16][17][17a][29] Indeed, a literature search confirms that among scholarly and research papers we researched for this article, not one authority detected the presence of either of the two types of mildew (Oidium-Erysiphe - powdery mildew, or Peronosporaceae - downy mildew) among the various fungi found growing on books, papers, photographs, stamps, or other paper based works. [1] op. seq. Fungal species commonly identified as found growing on or in books, papers, photographs, stamps, etc. include at least the following:

Aspergillus sp.
Aspergillus melleus [brownish stains, visible microscopically]
Aspergillus sclerotiorum [pale brown stains on paper, visible microscopically]
Cladosporyum sp. [Cladosporium sp. - ed.]
Cladosporyum sphaerospermum [pale brown stains on paper]
Penicillium sp. [at least 5 different species or strains]
Penicillium purpurogenum [brownish-yellow stains; pale whitish stains, visible microscopically]
Pithomyces chartarum [often appearing black on surfaces, brown or dark brown stains visible microscopically]
Ulocladium alternarie
Yeast [species to be identified]

How to remove & prevent Foxing stains: Cures for Foxing on Paper, Books, Photographs

Conservationists and paper or book restorers typically use a range of chemical or plant extract treatments to attempt to neutralize the reddish stains associated with foxing. Removing ferrous oxide (FeO) from the paper appears to be a key step in both removing the stains and preventing their recurrence. Where appropriate, such as in visibly moldy books and papers, mold needs to be physically removed from paper and book surfaces first, typically by gentle brushing, wiping, or HEPA vacuuming. Some conservationists also attempt to "kill" the mold using microwave or freeze-drying methods.[16]

Watch out: killing mold simply means that most of the remaining mold spores, if placed in a culture media, will not reproduce. But depending on mold genera/species such spores may still be harmful to humans or other animals and may retain allergenic or even toxic chemicals such as mycotoxins found in some fungi. For this reason, a proper mold remediation strategy should always involve physically cleaning mold from materials and surfaces that can be cleaned, and correcting the conditions that caused the mold growth in the first place. See MOLD KILLING GUIDE for details.

Gas bleaching: bleaching foxed documents with chlorine dioxide gas, combined with de-acidification [35]
Laser treatments for foxing: Sarantopoulou et als. have explored and demonstrated successful removal of foxing stains in paper using lasers at particular wavelengths. [27]
Plant extract and paper amendment treatments for foxing: Tronson has developed a refined foxing removal method that considers the details and condition of the paper itself and uses plant extract treatments to remove the iron oxide staining material as well as additional steps to restore and preserve the paper fibers, sizing, and other components. [25]
Anti-fungal treatments for foxing prevention: S. Sequeira et als have researched and report on the efficacy of antifungal treatments for the prevention of foxing damage to valuable books and papers. The focus is on prevention, not removal or cure for foxing stains. [28]
Chemical treatments for foxing: For the removal of foxing stains on paper such as stamps and other paper materials, Coleman recommended a now-obsolete procedure that used, in order of increasing severity, immersion in solutions of washing soda, chloramine, sodium chlorite, and potassium permanganate plus oxalic acid. [26]

Watch out: Calvini has warned at this article's FAQs section of this article that procedure #5 above is obsolete, dangerous, and can cause blindness. We list it here only so that readers can recognize it and thus stay away from it.

Watch out: Separately, Tronson warns

There has been no definite cure for neutralising the mildew [it's mold not mildew - Ed] spore, chemical use not only breaks down the paper cellulose but also reactivates the ink so not only do the fibres of the paper break down, after a while and the paper starts to disintegrate and the ink or what ever medium can be rubbed off!
...
Bleach treated or chemical treated papers on the other hand will always be subject to the foxing returning and eventual disintegration. [25]

Is there a distinction between "mold" and "mildew" appearance on books & papers?

As a book collector and once-upon-a-time mycologist I found your web site of interest.

However, I do not believe there would be uniform acceptance among professional mycologists of your distinction between "mold" and "mildew". The organisms involved are all fungi in the classical sense. Those attacking dead organic matter like cellulose are not all that different biologically from their relatives that may have a preference for the living cells of plants and animals.

The fact that some parasitic species may be facultative heterotrophs (feeding on non-living materials) supports this view. I believe your cause is best served by promoting the idea that the fungi, a diverse and highly successful breed, will exploit any environment where nutrients and moisture are available whether or not it is living or dead. Books and their bindings in a high humidity environment are sitting ducks.

... [text omitted here]. - Chris 9/7/2012

See our article BOOK MOLD, Moldy Book Cleaning and its section on the Distinction between "mold" and "mildew" on books and in general is questioned & answered for additional details about the importance of the distinction between mold growth on surfaces and mildew growth.

Mildew doesn't grow on books, nor on leather shoes, nor on wallpaper, nor on other indoor building surfaces, though lots of other mold genera/species might

Chris,

Thank you for the interesting comments about book mold, mildew, HEPA vacuuming, and the important role of the fungi in our environment. I'm grateful to read your opinion and want to emphasize that we welcome polite, informed discussion or debate about this or any other topic found at InspectApedia.com.

Indeed even among expert book restorers the term mildew is often used loosely and technically incorrectly to refer to the role of certain fungi or mold genera/species in the cause of foxing on books and papers. A few points need clarification: by no means do I suggest that mildew is not a fungus, as mildew is indeed a proper subset of the huge kingdom of fungi. But the fungi appearing on books are different genera/species from the two fungi properly named mildew. There are some important distinctions to be made.

Mildew doesn't grow on shoes, nor on paper, though many other mold genera/species can grow on these materials

I learned about the distinctive properties of mildew as a living plant pathogen among other members of the Fifth Kingdom from Dr. John Haines, my friend and mentor, when John was still serving as the NY State mycologist. Discussing some mold samples I'd brought along for us to examine, I mentioned that I'd just collected some white mildew from leather shoes found in a moldy home. Like many people I just bandied the word mildew about willy-nilly. John asked why I thought it might be mildew, allowed me to embarrass myself, and then kindly explained that mildew grows on plants, not shoes.

Perhaps it's technical nitpicking, but mildew a subset of "mold" that only grows on living plants. Mildews are a small group of fungi found among the Basidiomycota, Ustilaginales if I recall correctly, and any "mildew" if properly identified, will be either Oidium-Erysiphe or Powdery Mildew or Peronosporaceae or Downy Mildew. Mildew, then, has nothing to do with and won't be found growing on books nor on other building surfaces unless the item in the building is a live or recently-live plant.

The fungi identified as mildew include these two groups

Below I include photos of Oidium or powdery mildew that I collected from a jasmine plant (below left) that was growing indoors (we moved it outside before this photo was taken) along with a photo of the same mildew from that plant under my lab microscope (below right).

Typical library bookshelf dust (C) Daniel Friedman

Watch out: In a library of moldy books, if by careless language we informed building management that we thought the dominant mold present was just a bit of mildew (say Oidium) we would erroneously conclude that other than a possible allergic response or perhaps a problem for nearby houseplants, there was no health risk to building occupants. But in point of fact what I find on moldy library books is typically a potpourri of fungi dominated on book jackets by several species of Aspergillus - far more likely to present an IAQ and health hazard to occupants.

See Distinction between "mold" and "mildew" on books and in general is questioned & answered for additional details about this distinction.

Frequently Asked Questions (FAQs) about foxing stains on books, papers, photos: causes, cures, prevention

Comment: correcting the record on Foxing and Foxing Stain Removal Techniques

I have read the article about I'm one of the authors quoted in the bibliography (16, 17: Zotti et al.).

In the article published by Inspectapedia there are some questionable statements:

1) Iron Oxide (FeO) has nothing to do with foxing. It represent the "scaling" of Iron and is generally inactive on paper documents.

2) Perhaps the author confuses it with Iron Oxy-Hydroxide (FeOOH) responsible of "rusting". Rust can be easily detected, and can not properly labelled as foxing.

3) The chemical origin of foxing is thought to be due to the fact that that Iron Ions [i.e., Fe(II) and Fe(III)] catalyse the oxidation of paper, yielding the yellow-brown stains. These stains belong to the organic chemistry of cellulose and gelatine.

4) Perhaps we were not clear in our articles, but we mean that "sometimes" the (dead) fungal bodies can be mechanically removed, thus explaining their absence in several SEM analyses. The FTIR analysis shows that fungi stained the fibres, and these stains can't be removed mechanically.

5) The reccommendation after Coleman [26] are out-to-date and potentially very dangerous: should not be described in detail in Inspectapedia, otherwise not trained people may apply them in a blind way, as they find only this receipt fully described.

Sincerely, Paolo Calvini [16][17][17a][17b]

Reply:

Sr. Calvini:

I cannot thank you enough for taking the time to send me your note.. I have edited the article above to reflect your warnings.

As a matter of editorial policy we ask for expert technical review of our articles, while at the same time,we understand that we should not burden experts with too great a volume of requests. Had I considered that risk was involved I might have been smarter by asking for further reviews. - Daniel Friedman, Editor.

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Technical Reviewers & References

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American Institute for Conservation of Art and Historic Artifacts (AIC), 1717 K Street NW, Suite 200, Washington, DC 20006 Phone 202-452-9545 Website: http:/aic.stanford.edu/
[1] Book Conservation, Department of Preservation & Collection Maintenance, Cornell University Library, Website: http://www.library.cornell.edu/preservation/operations/bookconservation.html - quoting:
Conservation staff will advise and assist the public with regard to water, mold or insect damage and offer advice on storage and environment. The book conservation unit is a resource for libraries, organizations, and individuals outside Cornell. The following book preservation publications are available to the public at the Cornell University Library website: http://www.library.cornell.edu/preservation/publications/index.html
- Air Drying of Wet Books, Cornell University pamphlet, gives critical advice on how to handle books that have been wet. Original source: http://www.library.cornell.edu/preservation/publications/documents/AirDryingofWetBooks.pdf
- Disaster Response Plan, Cornell University Library, Disaster Subcommittee, Department of Preservation and Collection Maintenance, Security and Library Safety Working Group, Cornell University Library, Ithaca, NY 14583, Rev. July 2006.
  Includes advice on preserving books following a disaster, storm, water, etc. including book drying and book cleaning methods following a water or flood disaster.
- Pigment Particle & Fiber Atlas for Paper Conservators, Claire McBride, Getty Trust Postgraduate Fellow 2002, see http://www.library.cornell.edu/preservation/publications/mcbride.html [draft, incomplete, unedited] includes pigment atlases for Eastern pigments and fibers, Western pigments and fibers, and combined sources.
- Preserving Books in Your Home Library, Cornell University Library, original source: http://www.library.cornell.edu/preservation/publications/PreservingBooks.pdf
[2] Book Conservation Internship Program, U.S. Library of Congress, see http://www.loc.gov/preserv/int_book.html
Canadian Conservation Institute (CCI), 1030 Innes Road, Ottawa ON K1A 0M5, Canada, Tel: 613-998-3721, Website: http://www.cci-icc.gc.ca/html/
Conservation on Line (CoOL), http://palimpsest.stanford.edu/
[3] Frost, Gary, Teaching Book Conservation Methods Within a Training Program, The Book and Paper Group Annual, Vol. Five 1986, Book & Paper Specialty Group, AIC, Chicago 1986. Gary Frost, Asst. Professor, School of Library Service, Columbia University. Web-search 02/23/2011, original source: http://cool.conservation-us.org/coolaic/sg/bpg/annual/v05/bp05-13.html
[4] Godsey, Joyce, Book Repair for Booksellers: A Guide for Booksellers offering practical advice on book repair, CreateSpace (April 22, 2009), ISBN-10: 1442137320, ISBN-13: 978-1442137325 [author is a bookseller trained in book conservation and repair].
[5] Greenfield, Jane, The Care of Fine Books, Skyhorse Publishing; Reprint edition (September 1, 2007), ISBN-10: 1602390789, ISBN-13: 978-1602390782. Quoting from Amazon.com product description:
Jane Greenfield, advisor in rare book conservation at Yale University Library, is a leading authority on preservation and repair. After attending the New York School of Applied Design, she operated her own bindery for several years, enabling her to write from an unusual level of both education and experience. Here she offers a concise yet thorough discussion of book construction, storage, handling, cleaning, and repair, as well as essential expert advice on how to properly store and handle books of value in order to protect them from fire, flood, theft, and common wear and tear. With a new introduction by bestselling author Nicholas A. Basbanes, this is an indispensable volume for bibliophiles of every description.
[6] Guild of Book Workers, 521 Fifth Avenue, New York, NY 10175-0038, National Organization for all the Book Arts, Website: http://guildofbookworkers.org/
Heritage Preservation (HP), 1012 14th Street, NW Suite 1200, Washington, DC 20005, Tel: 202-233-0800, Website: http://www.heritagepreservation.org/
[7] Johnson, Arthur W., The Practical Guide to Book Repair and Conservation, [may not be available]
[8] Lavender, Kenneth, Book Repair: A How-to-Do-It Manual (How-to-do-It Manuals for Libraries, No. 107) (How to Do It Manuals for Librarians), Neal-Schuman Publishers; 2 Sub edition (February 1, 2001), ISBN-10: 1555704085, ISBN-13: 978-1555704087 - Quoting:
Lavender's highly acclaimed guide has been completely revised and expanded to offer up-to-date help. Covering both basic book repair techniques and sound conservation practices, this completely revised step-by-step manual offers illustrated sections on cleaning, mending, hinge and spine repair, strengthening paperbacks, and more. Completely new chapters cover: wet and water-damaged books; mold and mildew; repair of book linings and pamphlet bindings; using acid-free materials to repair damaged books; lining paper objects; affordable repair tools and supplies and much more. A full discussion of when and how to make repairs, and alternative conservation practices that enable each librarian to develop procedures appropriate to his or her library are also provided. Here is the practical guidance you need to successfully perform archivally-sound repairs - even on a limited budget.
[9] McQueen, Sharon, Latorraca, Ellen, Warmbold, Richard, In-House Bookbinding and Repair, The Scarecrow Press, Inc. (September 26, 2005, ISBN-10: 0810852241, ISBN-13: 978-0810852242, Quoting:
In-House Bookbinding and Repair is a working document that contains information on setting up both a basic bookbindery and repair lab (i.e. the design, equipment, tools, and supplies needed) and instructions on rebinding and repairing cloth-bound books. Highly illustrated to greater enhance its usefulness, this manual also covers various aspects of book repair and conservation, and contains appendixes on manufacturers and suppliers of materials and products discussed in the text, an extensive Glossary of terms, a separate section on World Wide Web Resources, and a helpful bibliography. This manual will prove valuable to libraries of all sizes and locations.
National Park Service (NPS), Conserve-O-Gram [museum management series], Website: http://www.cr.nps.gov/
NEDCC, "Preservation of Library & Archival Materials: A Manual", Northeast Document Conservation Center (NEDCC), 100 Brickstone Square, Andover, MA 01810-1494, Tel: 978-475-6021 Website: http://nedcc.org/
[10] Rosenberg, Margot, Marcowitz, Bern, The Care and Feeding of Books Old and New, St. Martin's Griffin (March 1, 2004), ISBN-10: 0312326033, ISBN-13: 978-0312326036. [Authors are owners of Manhattan's Dog Lovers' Bookshop]
[11] Schecter, Abraham A., Basic Book Repair Methods,
[12] Swifter Sweeper Dry Sweeping Cloths, Unscented, [at Amazon, also at grocery stores, cleaning suppliers] [ Note: Amazon pays us a small pittance when items are purchased through the link above - Ed.]
[13] HEPA Vacuum Cleaners, HEPA-Rated [at Amazon.com - Note: Amazon pays us a small commission on purchases through this store]
- C-Backpack HEPA 10 Q Vacuum Cleaner - HEPA (recommended for professional and large project book and library cleanup projects)
- Dustless Technologies 6-gallon HEPA Vacuum Cleaner (small shop vac size)
- Eureka 2694F Pet Lover Mighty Mite (floor canister - may be suitable for book cleaning)
- Eureka 4870MZ Boss Smart-Vac Upright HEPA Vacuum Cleaner (upright)
- Hoover Platinum Upright Lightweight Vacuum Cleaner - HEPA (upright)
- Rigid WD1450 14-BGallon 6-HP Wet/Dry Vac - HEPA (shop vac size), may be too powerful?
- Sunpentown V-8506 Bagless Upright Vacuum Cleaner (upright)
[14] Verheyen, Peter D., Basic Paper Treatments for Printed Book Materials, presentation, Guild of Book Workers 9th Anniv. Seminar, Portland OR, 1989, web search 02/23/2011, original source: http://www.philobiblon.com/gbwarticle/gbwjournalarticle.htm Quoting:
Since these presentations and the synopses that later appeared in the GBW Newsletter, there has been some discussion. The presentations and these articles are not to be construed as a "how to" of basic paper conservation but rather as an introduction for those with interest but little experience. For the more experienced, they present the methods of the individual conservator for dealing with common problems. None of these methods is the only way to carry out a specific treatment. Each project has its own challenges and no two are alike. It is therefore important to continue to build our knowledge through both reading and the lessons of experience.
[15] Thanks to reader Mike Olsen for discussing the problem of how a lab can determine whether or not mold in a test sample is active or inactive - June 2010
[16] Zotti (2011): M. Zotti, A. Ferroni, P. Calvini, "Mycological and FTIR analysis of biotic foxing on paper substrates", International Biodeterioration & Biodegradation Volume 65, Issue 4, July 2011, Pages 569–578, [copy on file as Zotti_2011.pdf]
Abstract The small rusty stains (foxing) frequently found on historic paper documents, books, and prints have generally been analysed in the past by optical microscope through their morphochromatic appearance under visible light and UV radiation. Despite increased research efforts with more sophisticated techniques (mainly SEM and XRF), the biotic or even chemical origin of these stains remains unclear. The purpose of this paper is to verify to what extent a simple technique such as FTIR-ATR spectroscopy can be utilised for a clearer understanding of the controversial nature of foxing. Since this technique is sensitive to several organic chemical groups that are in common with both fungi and gelatine-sized ancient paper, some modern cardboards stained by biotic foxing have been selected for the analyses. The results clearly show the importance of FTIR and mycological analyses for the identification of residual microfungal agents, together with the by-products of their activity on paper substrates. Keywords: Archaeometry; Foxing; Moulds; Fungi; Paper biodeterioration; Paper composition. Corresponding author. Tel.: +39 0103099378; fax: +39 0102099377. Email: milla@klaatu.com.dist.unige.it
[17] Zotti (2008): Zotti, Mirca,Ferroni, Alice, Calvini, Paolo, "Inhibition Properties of Simple Fungistatic Compounds on Fungi Isolated from Foxing Spots", Restaurator [Restaurator. International Journal for the Preservation of Library and Archival Material] Volume 28, Issue 3, Pages 201–217, ISSN (Print) 0034-5806, DOI: 10.1515/REST.2007.201, April 2008, online publication, Summary:
Only few solvents and chemical compounds are employable for the reduction of acidity and fungi in aged paper documents. In this study, we tested the fungistatic properties of calcium propionate (already proposed as deacidificant) either in aqueous or ethanolic solution. Further, we compared the effect of this treatment with that of a commercially available fungistatic spray based on 4-hydroxybenzoate and propyl 4-hydroxybenzoate. One set of tests was performed on fungi isolated from foxed old paper samples. Another was performed on a sheet of glass that had recently covered a cardboard backing in a frame and that showed a one-to-one correspondence between the spawn on the glass and the foxing stains on cardboard. Ten species representative of filamentous fungi genera and one yeast form were identified. Of the fungal species, the one most frequently represented was Penicillium, with 5 different strains, while for each of the other genera there was only one species. The antifungal chemicals investigated presented different levels of effectiveness in inhibiting micro-organism growth: the results of a number of tests carried out on strains cultured in suitable media demonstrate that saturated solutions (3.5 g/L) of calcium propionate in ethanol significantly inhibit the fungal growing.
[17a] Zotti (2008): M. Zotti, A. Ferroni, P. Calvini, Microfungal biodeterioration of historic paper: preliminary FTIR and microbiological analyses International Biodeterioration and Biodegradation, 62 (2008), pp. 186–194
[17b] Zotti (2007): Zotti, M., Ferroni, A., Calvini, P., 2007. Foxing biologico: diagnostica multidisciplinare. In: Atti del V Congresso Nazionale IGIIC e Lo stato dell’Arte e Cremona, 11e13 Ottobre 2007. Nardini Ed, Firenze, pp. 267e272.
[18] Book Repair Guide, Bookcraft®, supplier of book, paper & photograph conservation and restoration supplies; archival storage advice, Tel. 1-800-448-6160 Website: www.gaylord.com, retrieved 9/1/12, original site http://www.gaylord.com/images/Bookcraft_BookRepairGuide.pdf, [copy on file as Bookcraft_BookRepairGuide.pdf] and sources recommended by Gaylord:
- [19] Banks, Paul N. & Pilette, Roberta, Eds., Preservation Issues and Planning, Chicago and London: American Library Association, 2000
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- [23] Preservation of Library & Archival Materials: A Manual. 3rd ed. Andover, MA, Northeast Document Conservation Center, 1999
- [24] Young, Laura. Bookbinding & Conservation by Hand. Reprint edition. Newark, Delaware: Oak Knoll Press, 1995
[25] Tronson, Paul, "Removing Foxing and Mildew", Bookbinding & Royal Bindings-Commissions Accepted-Worldwide, Canada, Email: paul@periodfinebindings.com, Tel: +1 250 580 1547, retrieved 9/11/12, original source: http://periodfinebindings.typepad.com/removing_foxing_and_milde/ [copy on file as Removing_Foxing_Tronson.pdf]
[26] Coleman, M.H.; Baynes-Cope, A.D.; Agabeg, R.C., "Foxing", Chemistry and industry, Vol. 7, February 15, 1969, p. 197, three letters to the editor, quoting:

Watch out: as we note below, the following advice is out of date and dangerous. Do not follow it for removing foxing stains. Rather we repeate it here only so that readers can recognize these procedures that should not be followed:

These three letters to the editor discuss removal of foxing stains from philatelic materials. Coleman recommends, in order of increasing severity, immersion in solutions of 1) 0.25% washing soda, 2) 2% chloramine T, 3) 2% sodium chlorite with 2.5% formalin, or 4) 5% potassium permanganate followed by 2% oxalic acid. Paper requires re-sizing. Baynes - Cope recommends early detection by ultra violet (UV) light, and removal by oxidative bleaching in hypochlorites. Test for color sensitive materials (eg. manuscript inks) or gums. Prevent foxing (microbiological attack) by maintaining humidity (RH) at 50-60% with good ventilation (air circulation), or interleaving pages with paper impregnated with orthophenyl phenol fungicide or its' sodium salt. Agabeg describes treatment of stamps using 1-5% chloramine T. Color sensitivity should be tested using a blank. Loss of original gum will reduce a stamp's value. This article is a reference for the conservation of library, archival and philatelic materials, and works of art (eg. prints, drawings) on paper.

Watch out: As Calvini has explained at FAQs,

The reccommendation after Coleman [shown just above] are out-to-date and potentially very dangerous: should not be described in detail in Inspectapedia, otherwise not trained people may apply them in a blind way, as they find only this receipt fully described.
[27] E. Sarantopoulou [Email: esarant@eie.gr] , S. Kobe,Z. Kollia, A.C. Cefalas, "Removing foxing stains from old paper at 157 nm", Applied Surface Science, Volumes 208–209, 15 March 2003, Pages 311–316, Physics and Chemistry of Advanced Laser Materials Processing,
Abstract: Using a molecular fluorine laser at 157 nm foxing stains were removed successfully from a 16th century old paper. Laser cleaning of stains and foxing from old paper manuscripts is far more effective at 157 nm in comparison to different wavelengths without leaving any yellowish after-effect on the paper. This is because at 157 nm illumination of old paper, complete bond breaking of all the organic molecules of the paper is taking place. Mass spectroscopy at 157 nm and for moderate laser intensities up to 1 mJ/cm2 of old paper suffering from foxing indicate organic matter disintegration to small photofragments atomic, diatomic or triatomic, which are flying apart with supersonic speed. In addition high spatial resolution energy dispersive X-ray system (EDXS) analysis over the effected areas indicate the presence of iron, suggesting that biological activity is taking place preferentially in paper areas containing iron.
[28] S. Sequeira, E-mail: , E.J. Cabritab, M.F. Macedoc, "Antifungals on paper conservation: An overview", International Biodeterioration & Biodegradation Volume 74, October 2012, Pages 67–86,
Abstract & Highlights: Since its invention, paper has become one of the main carriers of our cultural, scientific, political, economic and historical information. Given the importance of this material, its preservation is a matter of great interest. Paper can be deteriorated due to physical, chemical and biological agents. Within microorganisms, fungi are the major paper biodeteriogens. Throughout history, several methods have been used to prevent and stop fungal deterioration on paper based materials. In this work we present a review of the main chemical and physical methods used to avoid fungal paper biodeterioration until nowadays and also of some new approaches tested recently. The advantages and disadvantages of these methods are discussed as well as their health effects. Studies regarding antifungal compositions, methods of application, performance and effects on the treated materials are also presented with the aim of providing a clear set of conclusions on the topic.
The use of antifungals on paper conservation is reviewed. Performance and effects on the treated materials of each antifungal method are discussed. The advantages and disadvantages of the antifungal methods are compared. Composition, methods of application and health effects are described. Two tables summarizing the results are presented.
[29] Sabrina Manente Email: manente@unive.it, Anna Micheluz, Renzo Ganzerla, Giampietro Ravagnan, Andrea Gambaro, "Chemical and biological characterization of paper: A case study using a proposed methodological approach", International Biodeterioration & Biodegradation, Volume 74, October 2012, Pages 99–108,
Abstract: One of the most important causes of paper degradation is biodeterioration, caused especially by fungi and bacteria under certain environmental conditions. This study was designed to check the presence of cellulolytic microorganisms on documents from the 19th century, and to verify any biodeterioration that may have occurred by using a series of predominantly non-invasive analyses in order to preserve their integrity. For the characterization of paper documents various non-destructive micro-analyses were performed in succession, so as to deepen our knowledge of these step by step and thus provide a logical approach for the general study of this type of artifact. The samples were analyzed by using light microscopy, histochemical tests, pH analysis, SEM–EDS observations, Fourier transform infrared (FTIR) spectroscopy in ATR, and GC–MS. Organic cultures were also made with the samples taken from the surfaces of the documents; in particular, four fungal species, Aspergillus sp., Penicillium sp., Cladosporium sp., and Ulocladium alternarie, have been identified, as well as the presence of bacteria and dust mites. Finally, relations/correlations between the results of chemical and biological analyses are discussed.
Highlights: The biodeterioration of paper is caused especially by cellulolytic fungi and bacteria. Characterization of paper documents with non-destructive micro analyses. SEM–EDS, FT-IR in ATR, GC–MS and organic cultures. Isolated: Aspergillus sp., Penicillium sp., Cladosporyum sp., Ulocladium alternarie.
[30] High Definition Infra Red, The Truth About What You Thought You Knew, FLIR Systems, Inc., 27700 SW Parkway Ave., Wilsonville OR 97070, USA, Tel: 800-727-3547, Website: www.FLIR.com, retrieved 9/11/12, original source: http://gs.flir.com/uploads/file/white-papers/hd-infrared.pdf [copy on file as FLIR_hd-infrared.pdf]
[31] Arai, H., 1984. Microbiological studies on the conservation of paper and related cultural properties: Part 1, isolation of fungi from the foxing on paper. Science for Conservation 23, 33e40.
[32] Arai, H., 1987. On the foxing-causing fungi. Preprints of the ICOM Committee for Conservation.
[33] Arai, H., 2000. Foxing caused by fungi: twenty five years of study. International Biodeterioration and Biodegradation 46, 181e188.
[34] Arai, H., Nemoto, C., Matsui, N., Matsumura, N., Murakita, H., 1989. Microbiological studies on the conservation of paper and related cultural properties: Part 8, on the components found in foxing. Science for Conservation 28, 7e15.
[35] Meynell, Guy, "Notes on Foxing, Chlorine Dioxide Bleaching and Pigments", Paper conservator, ISSN 0309-4227, Vol 4, No. 1, 01/01/1979 p. 30
[36] Henry A. Carter, The Chemistry of Paper Preservation: Part 1. The Aging of Paper and Conservation Techniques, Journal of Chemical Education 1996 73 (5), p 417
Abstract: This study provides an introduction to the problem of the aging of paper and the conservation techniques that are currently being employed in paper preservation. The chemical reactions that are responsible for the aging of paper are discussed with the conclusion that acid-catalyzed hydrolysis is the predominant mechanism for cellulose degradation and strength loss. A description and the chemistry of a number of mass deacidification methods are presented. The more viable deacidification methods include the DEZ, Wei T'o, FMC, Bookkeeper, Viennese, Book Preservation Associates, Sable and the Batelle processes. A summary of the literature on the evaluations of these processes is presented, and the benefits and limitations of the mass deacidification methods are discussed. Other conservation techniques such as paper strengthening, conservation bleaching, and pest control are briefly introduced, followed by an introduction to alkaline papermaking.
[37] Henry A. Carter, The Chemistry of Paper Preservation: Part 2. The Yellowing of Paper and Conservation Bleaching, J. Chem. Educ., 1996, 73 (11), p 1068 DOI: 10.1021/ed073p1068, November 1, 1996
Abstract: The discoloration of paper on aging is of interest to the archival community and also to the pulp and paper industry where new and improved mechanical pulps are being developed. The yellowing of paper on aging can be attributed to the presence of chromophores found in some of the products formed from the degradation of one or more components of paper. This study identifies the nature of the chromophores found in cellulose, hemicellulose and lignin. The photooxidation of lignin-containing papers and the mechanism for photoyellowing are discussed. This is followed by a description of the basic principles of conservation bleaching which involves chemically treating papers in order to remove unwanted discoloration or stains. The washing of paper and the use of oxidizing and reducing bleaches are presented. The discussion on oxidizing bleaches includes hydrogen peroxide, alkaline hypochlorite, chlorine dioxide and sunlight. The chemistry of reducing bleaches focuses on dithionites and borohydrides.
[38] Henry A. Carter, The Chemistry of Paper Preservation Part 3. The Strengthening of Paper, Journal of Chemical Education 1996 73 (12), p 1160
Abstract: The following study describes the parylene and graft copolymerization processes that have been developed to strengthen fragile or brittle paper artifacts. The parylene process involves vaporizing di-para-xylylene at 150o - 250 oC and splitting the dimeric parylene gas at 650o - 690 oC to mono-para-xylylene. The monomer vapor collides with the surface of the paper sample at room temperature and penetrates the cellulose fibers. Polymerization of the monomeric units to poly- para-xylylenes then occurs with the deposition of a thin uniform film. This parylene film forms mechanical links with broken fibers and strengthening occurs. The graft copolymerization (British Library) method involves treating papers with gaseous monomeric ethyl acrylate and methyl methacrylate, and initiating copolymerization by irradiating the papers with low intensity gamma rays. Webs of long-chained polymers are deposited on and between the cellulose fibers thereby strengthening the papers. The chemistry as well as modifications to both processes are discussed.
[39] Henry A. Carter, The Chemistry of Paper Preservation: Part 4. Alkaline Paper, Journal of Chemical Education1997 74 (5), 508
Abstract: The inherent instability of old papers is largely due to the presence of acids which catalyze the hydrolytic degradation of cellulose. The use of alkaline paper can minimize the problem of acidity for new papers. This study focuses on the chemistry involved in the sizing of both acid and alkaline papers and the types of fillers used. The waterproofing agent that is used in acid paper is alum-precipitated rosin size, which tends to spread and create a hydrophobic surfaces over the cellulose fibers. Alkaline paper uses the synthetic sizing agents, alkyl ketene dimers(AKD) and alkyl succinic anhydrides (ASA). These alkaline sizing agents become chemically bound to the cellulose fibers with hydrophobic chains pointing outward, producing a water repellent surface. The sizing reactions take place in a neutral-to-alkaline medium. Calcium carbonate can then be used as a filler to replace expensive titanium dioxide. Finally, the advantages and potential problems in alkaline paper making are discussed.
[40] Henry A. Carter, The Chemistry of Paper Preservation. Part 5. Permanent Paper Journal of Chemical Education 2007 84 (12), 1937
Abstract: The acid-catalyzed hydrolysis of cellulose accounts for the deterioration of paper in library books and other written records. To combat this threat to our written heritage, new permanent papers have been developed that are relatively chemically stable and undergo a very slow rate of deterioration. Many of these new papers are manufactured from mechanical pulps that contain large amounts of lignin, and are stable when a calcium carbonate buffer is present. Based on the performance involving accelerated aging of the papers, the inclusion of lignin has been accepted in the standards for permanent paper by Canada and Germany, providing that a calcium carbonate buffer is present. Other countries are still reluctant to make the change in standards to include lignin. Research needs to be done to define optical properties and their requirements for the standards. The applications of the chemistry of paper preservation to teaching are also discussed.

Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair

Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.

The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume. Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.

Or choose the The Home Reference eBook for PCs, Macs, Kindle, iPad, iPhone, or Android Smart Phones. Special Offer: For a 5% discount on any number of copies of the Home Reference eBook purchased as a single order. Enter INSPECTAEHRB in the order payment page "Promo/Redemption" space.

Building inspection education & report writing systems from Carson, Dunlop & Associates Ltd

Carson Dunlop, Associates, Toronto, have provided us with (and we recommend) Carson Dunlop Weldon & Associates' Technical Reference Guide to manufacturer's model and serial number information for heating and cooling equipment
Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on any number of copies of the Technical Reference Guide purchased as a single order. Just enter INSPECTATRG in the order payment page "Promo/Redemption" space.
Environmental Health & Investigation Bibliography - our technical library on indoor air quality inspection, testing, laboratory procedures, forensic microscopy, etc.
Adkins and Adkins Dictionary of Roman Religion discusses Robigus, the Roman god of crop protection and the legendary progenitor of wheat rust fungus.
Kansas State University, department of plant pathology, extension plant pathology web page on wheat rust fungus: see http://www.oznet.ksu.edu/path-ext/factSheets/Wheat/Wheat%20Leaf%20Rust.asp
"A Brief Guide to Mold, Moisture, and Your Home", U.S. Environmental Protection Agency US EPA - includes basic advice for building owners, occupants, and mold cleanup operations. See http://www.epa.gov/mold/moldguide.htm
US EPA - Mold Remediation in Schools and Commercial Building [Copy on file at /sickhouse/EPA_Mold_Remediation_in_Schools.pdf ] - US EPA
US EPA - Una Breva Guia a Moho - Hongo [Copy on file as /sickhouse/EPA_Moho_Guia_sp.pdf - en Espanol
"A Brief Guide to Mold, Moisture, and Your Home", U.S. Environmental Protection Agency US EPA - includes basic advice for building owners, occupants, and mold cleanup operations. See http://www.epa.gov/mold/moldguide.htm
"Disease Prevention Program for Certain Vegetable Crops," David B. Langston, Jr., Extension Plant Pathologist - Vegetables, University of Georgia (PDF document) original source: www.reeis.usda.gov/web/crisprojectpages/209797.html
"Disease Prevention in Home Vegetable Gardens," Patricia Donald, Department of Plant Microbiology and Pathology, Lewis Jett
Department of Horticulture, University of Missouri Extension - extension.missouri.edu/publications/DisplayPub.aspx?P=G6202
"Management of Powdery Mildew, Leveillula taurica, in Greenhouse Peppers," Ministry of Agriculture and Lands, British Columbia - Original source: www.agf.gov.bc.ca/cropprot/peppermildew.htm
Fifth Kingdom, Bryce Kendrick, ISBN13: 9781585100224, is available from the InspectAPedia online bookstore - we recommend the CD-ROM version of this book. This 3rd/edition is a compact but comprehensive encyclopedia of all things mycological. Every aspect of the fungi, from aflatoxin to zppspores, with an accessible blend of verve and wit. The 24 chapters are filled with up-to-date information of classification, yeast, lichens, spore dispersal, allergies, ecology, genetics, plant pathology, predatory fungi, biological control, mutualistic symbioses with animals and plants, fungi as food, food spoilage and mycotoxins.
Fungi, Identifying Filamentous, A Clinical Laboratory Handbook, Guy St-
US EPA: Mold Remediation in Schools and Commercial Building [Copy on file at /sickhouse/EPA_Mold_Remediation_in_Schools.pdf ] - US EPA
Mycology, Fundamentals of Diagnostic, Fran Fisher, Norma B. Cook, W.B. Saunders Co. 1998, ISBN 0-7216-5006-6 (buy this book at Amazon)


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