Foxing Stains Research Articles

Paper Foxing Stains on a Historic Manuscript from the Early Qajar Era: Abiotic or Biotic Foxing?

The aim of this study was to identify the nature and cause of foxing spots in a historical manuscript. This manuscript was a Holy Quran from the beginning of the Qajar period and the end of the 18th century. Samples were incubated for 14 days and were evaluated for the presence of fungal activity. UV fluorescence photography, micro X-ray fluorescence spectroscopy and Fourier transform infrared spectroscopy were also used to investigate the characteristics and causes of foxing spots. The results showed that there was no fungal activity in the foxing spots of this manuscript. Based on the morphology of the stain in UV fluorescence photography, these foxing stains are of the Bullseye type, usually associated with metal ions. µXRF spectroscopy also showed a high accumulation of iron and copper at the site of these spots. This indicates abiotic foxing in this manuscript. Based on FTIR spectroscopy and peak deconvolution and fitting by Gaussian function, abiotic foxing increases the cellulose oxidation rate. Intensification of cellulose oxidation in foxing stains can be considered as one of the reasons for paper discoloration.

Characterization of an early 20th century Chinese manuscript with foxing stains

Foxing spots are reddish-brown, brown, or yellowish spots in irregular shapes that are commonly discovered on paper materials. Effects of such foxing spots on degradation of Chinese papers have rarely been reported. In this study, a 20th century Chinese manuscript with few foxing stains was examined to explore the cause of stain formation. The paper areas with foxing stains were more acidic than those without the stains, while no obvious differences in cellulose crystallinity and iron and copper contents were observed when comparing paper areas with and without foxing spots via X-ray diffraction (XRD) and energy-dispersive X-ray fluorescence spectroscopy (ED-XRF), respectively. For further exploration, few fungal hyphae and spores in various sizes were observed using SEM, leading to increased mean roughness of the paper surface for the foxed area. This is further supported by the presence of amide II in the foxed area only, as detected via attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy. Fungal culture was then carried out to demonstrate that fungi belonging to the genera Alternaria tenuissima and Alternaria solani were present. This research provides an improved understanding of the effects of foxing spots on Chinese archives and informs of further conservation efforts.

Evaluation of Carboxymethyl Cellulase Activity as an Indicator of Active Moulds Inside Foxing Spots on Paper

ABSTRACT Foxing is a special case of fungal deterioration on paper, recognizable by spots of yellowish to brownish colours. Measuring the carboxymethyl cellulase activity (CMCase) by 3,5-dinitrosalicylic method was used to assess the presence of active cellulase inside foxing stains. This was done on foxed paper samples and compared with five fungal strains (belonging to the species Eurotium herbariorum, Talaromyces atroroseus, and Penicillium minioluteum) with cellulolytic capacity, previously identified inside foxing spots, and a highly cellulolytic strain of Trichoderma viride, as a reference. The highest activity of T. viride, expressed as the reducing equivalent glucose released (mg L−1), is achieved at 26°C and in Czapek medium supplemented with carboxymethyl cellulase and sucrose. In the same conditions, for all strains, the activities reached their highest value on the seventh day and then decreased. The method was sufficiently sensitive to indicate the presence of CMCase activity inside foxing spots. These cellulase activities cause paper degradation even after the fungus dies, as the excreted enzymes remain active on the substrate.

Considerações sobre manchas de foxing em três colecções de papel dos séculos XVI a XX

Three surveys on the occurrence of foxing stains were carried out on papers dating from 1560 to 1975 in three Portuguese collections. Foxed papers were found to be more intensely and intrusively stained in certain time periods of each collection. Based on historical data and on the professional paper conservation experience, the authors linked the increased occurrence of foxing stains in certain time periods to the new papermaking processes and materials, which began to be introduced in the late 18th century, and in particular to a synergistic effect between three factors: the use of deficient gelatine sizing which began to present a poorer quality and homogeneity, the presence of iron-containing impurities throughout the paper leaf and a distinct sorbency of moisture. Observing batches of morphologically similar papers by using photographic imaging with different types of light sources and incidences, the authors verified that similar papers present similar foxing stains.

Foxy Underpants: Or the Use of Chelators and Enzymes to Reduce Foxing Stains on Early Nineteenth Century Men’s Linen Underpants

ABSTRACT This paper describes a successful treatment to reduce foxing stains on a pair of men’s linen underpants ca. 1830 in the collection of the Costume Institute at The Metropolitan Museum of Art. The underpants are ankle length and have a wide corset-like waistband containing 12 baleen stays. Such undergarments are rare in museum collections, yet provide a reminder of the importance of fashionable bodies for men. Foxing stains can be disfiguring on any work of art, but the stains were considered particularly distracting on the underpants. While foxing stains are a common problem in textile collections, most recent studies have focused on paper collections. Building on research by paper conservators and scientists, this treatment addressed the metals and microorganisms that cause foxing stains. Rather than use bleaching agents, the underpants were wet-cleaned in a series of baths with the chelator ethylenediaminetetraacetic acid, a lysing enzyme, and the surfactant sodium lauryl sulfate. An agarose poultice with hydroxybenzyl ethylenediamine was used to target an area with dark stains. In both visible and ultraviolet light, the stains showed considerable reduction after the treatment.

Image-Based Quantitative Analysis of Foxing Stains on Old Printed Paper Documents

We studied the feasibility of image-based quantitative analysis of foxing stains on collections of old (16th–20th century) European books stored in the Rare Book Library of the Seoul National University in Korea. We were able to quantitatively determine the foxing affected areas on books from their photographs using a newly developed image processing software (PicMan) including cultural property characterization applications, specifically. Dimensional and color analysis of photographs were successfully done quantitatively. Histograms of RGB (red, green, blue) pixels of photographs clearly showed the change in color distribution of foxing stains compared to the other areas of the photographs. Several sample images of quantitative measurement of foxing stains and virtually restored images were generated to provide easy visual inspection and comparison between restored images and the original photographs. Image quality, resolution, and digital file format requirements for quantitative analysis are described. Image-based quantitative analysis of foxing stains on paper documents are found to be very promising towards automation for objective characterization of photographs of cultural properties. This technique can be used to create a cultural property digital database. Quantitative and statistical analysis techniques can be introduced to monitor the effect of storage and conservation environment on the cultural properties.

Analysis of paper foxing by newly available omics techniques

The aim of this study was to determine the cause of foxing on 19th century paper using omics methods, including metagenomics via high-throughput sequencing on the Illumina platform and metabolomics via high-resolution surface-assisted laser desorption/ionization time-of-flight mass spectrometry (SALDI-ToF-MS) imaging using the gold nanoparticle-enhanced target (AuNPET) method. Metabolomic analysis as well as ninhydrin and amido black staining of paper samples showed the presence of proteinaceous substances in areas corresponding to foxing. Products of cellulose biodegradation and microbial metabolites, including yellow-coloured pigments (2-methyl-6-phytylquinol; delta-, gamma- and beta-tocopherols; 3-hydroxy-L-kynurenine) were detected. No difference in metal-ion content was seen between areas with and without foxing. Higher degrees of biodiversity were identified within foxing stains compared to foxing-free areas. Phoma sp. and Cladonia sp. moulds and Gluconobacter and Ralstonia bacteria were predominant in DNA samples obtained from foxing stains. The presence of these microbes has never previously been linked to the phenomenon of foxing. These studies indicate that foxing is a result of a combined effect of microbial action, paper-degradation by microbes, dye production, and chemical changes occurring in paper due to oxidation of cellulose metabolites.

Electrochemical removal of stains from paper cultural relics based on the electrode system of conductive composite hydrogel and PbO2.

Constructing methods for cleaning stains on paper artworks that meet the requirements of preservation of cultural relics are still challenging. In response to this problem, a novel electrochemical cleaning method and the preparation of corresponding electrodes were proposed. For this purpose, the conductive graphene (rGO)/polyacryamide (PAM)/montmorillonite (MMT) composite hydrogel as cathode and PbO2-based material as anode were prepared and characterized. The electrochemical cleaning efficiencies of real sample and mimicking paper artifacts were evaluated, and the effects of the electrochemical cleaning on paper itself were detected. Based on the above experiments, the following results were obtained. The composite hydrogel with attractive mechanical properties is mainly based on the hydrogen bond interactions between PAM chains and MMT. The results of cleaning efficiency revealed that the black mildew stains together with the yellowish foxing stains were almost completely eliminated within 6 min at 8 mA/cm2, and various stains formed by tideline, foxing, organic dyes and drinks could be thoroughly removed at 4 mA/cm2 within 5 min. In addition, the proposed cleaning method has advantages in local selectivity, easy control of cleaning course, and reusability, which represents a potential utility of this approach.

Microbial Life and Death in a Foxing Stain: a Suggested Mechanism of Photographic Prints Defacement.

The gelatin-silver halide black and white prints represent an enormous photography heritage with a great value. Unaesthetic phenomena, the foxing stains that are caused by microbial growth on surface, have been described in stamps, drawings, books, and tissues but, until now, scarcely for photographic materials. In this study, a combination of various techniques, including culture-dependent and culture-independent approaches (RNA and DNA analysis), scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) and μ-Raman spectroscopy supported by X-ray fluorescence analysis (XRF), permitted to describe the microbial contamination dynamics of foxing stains present on the surface of two gelatin-silver halide photographs. The investigation provided also information on the effects of microbial activity on the materials' chemistry of the two prints. The action of microbial community resulted locally in either (a) formation of mixed aluminum-iron-potassium phosphate compounds that could be attributed to the hydrolytic activity of bacteria, (b) leaching of barite,

Characterization of foxing stains in early twentieth century photographic and paper materials

The subject of this present work is a group of nine historical pictures shot in Palermo by the Sicilian photographer E. Interguglielmi in 1912. They are nine matte-collodion prints mounted on the original cardboard supports and all of them show foxing stains affecting the paper surface. In order to characterise the chemical composition of the supports and investigate foxing spots, non-destructive and micro-destructive analysis were carried out. X-rays fluorescence (XRF) analysis was used to characterise the elemental composition of all the mounting boards, allowing a comparison between the foxing spots and non-affected areas. Laser-Induced Breakdown Spectroscopy was used to investigate the presence of lower atomic number elements, not detectable by XRF, while SEM imaging allowed the investigation of surface appearance and nature of original paper samples from the cardboards.

Multi-analytical characterization of paper samples exhibiting foxing stains.

Multi-analytical characterization of paper samples exhibiting foxing stains.

Multi-analytical characterization of paper samples exhibiting foxing stains

Multi-analytical characterization of paper samples exhibiting foxing stains

Contribution to the characterization of foxing stains on printed books using infrared spectroscopy and scanning electron microscopy energy dispersive spectrometry

This study is part of research on the biological foxing formation affecting some old documents and explores the potential of ATR-FTIR spectroscopy to characterize foxing spots on paper from nine printed books, dating from early 19th century to mid-20th century. Preliminary assays allowed to highlight clear differences in FTIR spectral profiles between molds and the paper substrate on which they grew. However, spectra of foxed paper spots showed solely the absorption bands of cellulose due to very low amount of fungal elements inside the spots. Foxing spots were successfully differentiated from unstained areas of the paper by a slight intensity increase in the 1500–1700 cm−1 region and the appearance of small representative band near 1520 cm−1 which could be used as a marker for biological foxing. Comparative elemental analysis by SEM-EDS was also carried out with the intention of revealing other significant differences between the inside and the outside of spots. At this stage of the study, the findings are not totally conclusive. However, the overall results achieved by these two techniques encourage further research to gain a better understanding of biological foxing.

Analytical and microbiological characterization of paper samples exhibiting foxing stains.

This work comprises the use of a multi-analytical approach combined with microbiological studies to characterize six paper samples, containing foxing stains, from the 20th century, regarding their cellulose matrix, fillers, and sizing materials, and to evaluate possible paper degradation that might have occurred during the foxing stains. Photography under different illuminations and optical microscopy were used for morphological characterization of the paper samples and foxing stains. Scanning electron microscopy coupled energy dispersive spectroscopy (SEM-EDS) was of particular importance for defining the presence of fiber disorder and disruption on the surface of some of the stains, and localized accumulations of mineral-like particles on the surface of others. SEM-EDS, attenuated total reflection Fourier transform infrared spectroscopy (ATR-FT-IR), and energy dispersive X-ray fluorescence (EDXRF) were used for the identification of mineral fillers, whereas sizing agents were analyzed using ATR-FT-IR. EDXRF results showed that no differences, within the standard deviation, were found in iron and copper contents between the foxed and unfoxed areas. Fungi belonging to the genus Penicillium spp. were found in all the paper samples. Unfoxed areas presented lower contamination than the foxed areas.

Treating a Previously Bleached Artwork on Paper

AbstractThe case study describes the treatment of an etching that had been bleached in the past with 4% hydrogen peroxide and had subsequently suffered extensive colour reversion in the form of foxing and overall discolouration. Staining was most likely caused by the action of hydrogen peroxide on previously unnoticed iron particles in the paper. The print now underwent treatment to stabilize the damaged paper. The print was immersed for 50 seconds in 0.1 M hydrochloric acid HCl (pH 1.1) to extract as much as possible of the iron contamination from the paper; this was followed after rinsing steps by complexation of remaining iron ions through immersion in a calcium phytate solution (1.75 mmol/L, pH 5.3). The treatment, which included extensive rinsing, significantly diminished the foxing stains. No further bleaching treatment was conducted to diminish remaining stains so as not to risk further destabilization of the pre-damaged paper.

Characterisation of foxing stains in eighteenth to nineteenth century drawings using non-destructive techniques

The reddish-brown, brown or yellowish stains of circular or irregular shape known as foxing spots have been fully described in conservation literature but still, this phenomenon does not find any scientific agreement since many hypotheses have been raised concerning their origin. In this work a contribution to foxing definition not only focussed on its appearance but also reported on its chemical information. For this purpose foxing stains present in drawings from two Portuguese artists dated from the eighteenth to nineteenth centuries were observed under ultra-violet light and optical microscope and analysed by three non-invasive spectroscopy techniques. The observations carried out on the stains provided information on their surface morphology. The use of energy-dispersive X-ray fluorescence revealed a variation on the elemental content between foxing and paper region. Although the results from X-ray diffraction analysis showed no signs of cellulose degradation in foxing stains, Fourier-transformed infrared analysis revealed the presence of oxide groups. Both the information on the chemical nature and surface morphology of the stains achieved in this study will contribute to increase foxing formation information and develop future protocols for conservation purposes.

ATR-FTIR and FT Raman spectroscopy and laser cleaning of old paper samples with foxings

Samples of old paper are studied using ATR-FTIR and FT Raman spectroscopy. It is demonstrated that the methods of laser spectroscopy make it possible to distinguish between the foxing localization regions and the region of homogeneous aging (yellowing). A significant bleaching of old paper and an almost complete erasure of the foxing stains can be reached using laser irradiation.

Assessment of the Effect of Various Bleaching Agents on Papers with Foxing Stains

The study evaluated the effect of various chemical bleaching agents on the long-term colour stability of paper and on the discoloration caused by foxing stains. Five different historical paper samples, covered with foxing stains, were characterized. Several spots were tested for the presence of transitional metal ions using laser-ablation-ICP-MS; the fibre composition and pH of the paper were also determined. Colour changes, experienced by the discoloured areas and the paper after washing and deacidification and subsequent to the application of one of the five different bleaching solutions investigated, were followed using scanned images. CIELAB values were determined with Photoshop 7.0 software. The effect of different bleaching solution applications on the colour stability of the treated paper during thermal ageing was evaluated as well. Results indicate that when higher concentration of iron ions are present in the paper, treatment with the complexing agent EDTA and sodium dithionite efficiently brightens the foxing stains and the paper and improves their colour stability. In this study, it was shown that for papers with low transitional metal content, washing and deacidification, as well as the application of sodium borohydride, gave superior results when compared to hydrogen peroxide or calcium hypochlorite treatments.

Inhibition Properties of Simple Fungistatic Compounds on Fungi Isolated from Foxing Spots

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.

Removing foxing stains from old paper at 157 nm

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/cm 2 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.