BIODETERIORATION OF PAINTS PDF

INTRODUCTION. There is now a high level of acceptance amongst biodeterioration biologists and technologists in the paints and biocides industries , that. Several paints of varying chemistry have been in use for domestic and industrial purposes. The painted Biodeterioration of domestic and public buildings. PDF | This paper presents a review of the biodeterioration of architectural paint films by bacteria, fungi and algae, concentrating on external films. references .

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Biodeterioration and Biodegradation, 9. Biodeteriortion these damages one should add those inflicted by metabolites, often acidic in nature, and by extracellular enzymes excreted by microorganisms. Danin A and Caneva G Deterioration of limestone walls in Jerusalem and kf monuments in Rome caused by cyanobacteria and cyanophilous lichens. Their objectives were to study all aspects of the growth of fungi on applied surface coatings and to develop a standard method of test.

Dry-Film Algal Testing A similar process has been followed for the laboratory evaluation of paints intended to be resistant to algal growth.

BIODETERIORATION OF PAINT AND PAINT FILMS

This in turn could promote separation of the painted surface from the ground or of the ground from the masonry on which the fresco was laid. Two types of aesthetic damage were observed, white efflorescence and green-to-black stains.

Many of the components of paintings are biodegradable, and so are the additives glues, emulsifiers, thickeners, etc.

With few exceptions, the paintings, some as long as 5 m, represented different animals some imaginaryand their quality was such that the cave was designated by some the Sistine Chapel of the Paleolithic. Giacobini C, Firpi M. If, for any reason, control of humidity, temperature, and light, as occurs in museums, is not possible, then protection of objects of artistic or historical interest rests only on the intrinsic components of such objects that can render them refractory to microbial colonization.

Microbial Degradation of Paintings

Further, in laboratory experiments, they demonstrated that treatment with fungicides could arrest or prevent microbe-induced damage to paintings. It may be added that high levels of humidity, temperature, and light, as may be found, for instance, in warmer climates, may shorten the, one could say, life span of a painting by exacerbating the damages caused by paintd pollution, biological attack, and natural aging.

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Growth of Beauvaria alba on mural paintings in Canterbury Cathedral. Indeed, these organisms have been reported to contribute to the weathering process of masonry A hypogean algal association. For instance, from a fresco in St. A somewhat similar sequence of events was postulated by Karpovich-Tate and Rebrikova to occur on frescoes and masonry in a Russian cathedral Controlli microbiologici su alcuni affreschi fiorentini; pp.

Ottawa, September The analyses were essentially limited to the fungal population and demonstrated biodeteiroration clear differences existed between the numbers of species isolated from art works and those isolated from the environment in which the art work was located. The Biodeterioration Society, Kew. In this type of experiment only the viable counts of the fungi Aspergillus niger and Penicillium chrysogenum increased in the first period of incubation. However, wide quantitative variations are evident.

Ann Arbor Science Publishers, Inc. After these biodeteriotation papers, Gargani 14 and Tiano and Gargani 57 published a detailed investigation of the microbial floras of art works, mostly frescoes. Unlike Bacillus pumilusgrowth and survival on mock paintings of the bacteria isolated from the fresco were not stimulated by the presence of Aspergillus niger.

A list, certainly not exhaustive, of the organic components that may be present on paintings can be found in references 15 and Firstly by discussion at the meetings, secondly by carrying out and reporting on individual laboratory investigations and, most importantly, by organising, performing and reporting on collaborative experimental work or round robin testing.

Opificio delle pietre dure e laboratori di restauro di Firenze.

In this review a brief description of the paints and their compositions, paint properties, paint biodetoriation and biodegradation are described. Further, no attempt has been made to identify the species responsible for the damage, both aesthetic and biodeterioratkon, and the species that are just saprophytes living on the painted surface may be growing at the expense of other microorganisms colonizing the frescoes.

Further, Aspergillus nigerone of the most ubiquitous fungal contaminants, was isolated in only one case. Indeed, work under way in my laboratory has demonstrated the existence of differences in the microbial colonizations of mock paintings when different pigment binders oil or distemper were used or when the same type of painting was relined with different glues unpublished data.

A microbiologist should be asked to characterize the microbial flora present on a work of art when it appears to be still in its pristine condition and well before any alteration becomes evident. Extensive analysis of the composition of, and the variations in, the microbial population of the painted areas as well as of the unpainted rocks and the surrounding environment led to the conclusion that the population of Bracteacoccus minorresponsible for the maladie vertealso increased when the cave was closed to the public and kept in continuous darkness for long periods.

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However, sampling at different intervals months revealed significant differences in the compositions of the flora of the painted surface whereas there was little variation from sampling to sampling in the flora of the environment.

The painted surfaces undergo damage or discolored due to natural weathering, and the growth and activity of living organisms.

Biodegradation and biodeterioration in Latin America. Although dead bacterial cells adhering to the paint layer did stimulate growth of the fungus, further experiments provided evidence that bacterial colonization of the painted surface had chemically modified some of the components of the paint, rendering them utilizable by the fungus It sounds almost tautological to state that, besides the chemical composition of an art work, the environment conditions the development of a microbial flora, as it is quite obvious that a specific microbial flora will develop, for instance, on a fresco on the facade of a church where it receives a considerable amount of light and a different flora will develop on a similar fresco inside the same building in which light is very reduced.

Microbial Degradation of Paintings

Members of the genera AlcaligenesBacillusFlavobacteriumand Pseudomonas represented the most frequent bacterial species present at all times. Indeed, a previous report showed that Aureobasidium pullulans was unable to utilize hydroxyethylcellulose, a component of the paint, for growth but that it utilized this compound pretreated with cells of Pseudomonas or even with a cellulase produced by the bacterium In Lascaux Cave was opened to visitors, but in it was closed indefinitely to the public.

In laboratory experiments, 19 species of the fungi isolated from the two biodeterioeation were tested for the capacity to grow on the materials used for restoration calcium caseinate, animal glue, and masonite, used as biodeteerioration support panel.