Considerations about foxing stains in three paper collections ranging from the 16th to the 20th century

Abstract

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.

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

“…The color of foxing spots of the manuscript, under reflected light, appear to be orange-brown. Similar to the report of Francisca et al (2020) [17], under UV radiation, there is a round, well-delimited white fluorescent halo surrounding a non-fluorescent darker center. What is clear is that the halo extends beyond the visible stain (Figure 3).…”

“…Therefore, these stains should be considered abiotic foxing. One sign of foxing stains is their fluorescence under UV light [8,17,18]. The color of foxing spots of the manuscript, under reflected light, appear to be orange-brown.…”

Microbes on the “peachy spots” of ancient Kaihua paper: microbial community and functional analysis

“…Microscopic observation of the presence of mycelia has been used as a criterion to determine whether a stain is due to mold or mildew damage. The presence of UV fluorescence is used as a standard to define “foxing spots” ( Meynell and Newsam, 1978 ; Koochakzaei and Alizadeh Gharetapeh, 2021 ), but fluorescence is also considered by other researchers as a factor in the formation of “foxing” spots ( Bicchieri et al, 2001 ; Figueira et al, 2020 ). The peachy spots on the Kaihua paper resemble foxing spots by description, although in our previous tests, no UV fluorescence was observation at the spots (data not shown).…”

Research on detection method of foxing on paper cultural relics based on CNN and hyperspectral

“…If the paper cultural relics are stored in an improper way, the paper will easily produce reddish-brown, brown or yellowish foxing [1] . And in the foxing area, the paper becomes weaker and more brittle than the unaffected area [2] . If the foxing ais not effectively detected and scientifically controlled, the foxing will further expand, causing irreversible damage to the entire cultural relic.…”