Deterioration Of Paintings Research Articles

Evaluation of the corrosion resistance of painted steels by impedance measurements

The behaviour of six metal-paint systems exposed to accelerated corrosion tests, salt spray and Kesternich cabinet tests (humid air cycling with periodical addition of sulphur dioxide) has been investigated by the a.c. impedance technique. Regular inspections of rusting and blistering on painted surfaces were carried out. Adhesion evaluation was performed using pull-off tests after exposure to the various atmospheres. It was found that a.c. impedance measurements complement the results of the accelerated tests and provide comparative quantitative data and valuable information on the coating degradation mechanism. The impedance measurements associated with accelerated tests enable the early prediction of the paint deterioration in comparison with usual atmospheric exposure and help to anticipate the metallic corrosion at the metal/coating interface.

Fouling Control of Navy Surface Ships - 1990

1The Author The Author received a B.S. degree from the New York State College of Forestry, Syracuse University. He joined the staff of the Material Laboratory at the New York Naval Shipyard in 1951 and carried out applied research as a wood technologist in the foreign wood program for all wood minesweepers. In 1962, at the Naval Applied Science Laboratory, he was engaged as a rubber technologist in the development of elastomeric vibration damping materials and the Laboratory's research studies on marine fouling. Since 1970, at the David W. Taylor Naval Ship Research and Development Center, he has been a materials engineer involved with the Center's programs on deck coverings, corrosion and conservation of energy. He is a member of ASNE. ABSTRACT Ongoing investigations on three test ships covering a period of five years have identified the performance characteristics of an antifouling (AF) paint for long-term service. This paint ablates by the sequential hydrolysis of the surface and shearing action of the ship's passage through the water to remove the persistent settlement of microorganisms while continuously releasing an environmentally acceptable component to control calcareous fouling. During the past decade a variety of toxicants have been investigated and formulated into a number of AF paints that can be grouped on the basis of how the toxicant is combined and released from the paint matrix. Observations relative to color change, fouling and paint deterioration, define the qualitative criteria for evaluation. Quantitative data obtained with improved instruments for taking dry film thickness measurements and roughness determinations both in drydock and underwater accurately track these parameters during long-term service. Field studies have shown that ablation of the AF paint is an effective mechanism to limit the formation of microbial biofilms on AF paint surfaces. Field studies have also revealed that reliance on toxics will not control the accretion of microorganisms on a ship's hull. The ablative AF paint has been found to be superior to all non-ablative AF paints evaluated by the Navy to date.

Deterioration of anti-corrosive paints by extracellular microbial products

Abstract Microorganisms are frequently found on deteriorated coatings and their deteriogenic action can be demonstrated by testing them against sound coatings of the same composition. No blistering or loss or adhesion occurred on either biocide containing coatings or coatings tested under sterile conditions. The mechanism of the attack is largely unknown. It has been assumed previously that to bring about loss of adhesion and blistering, the microorganisms must penetrate the coating and act from beneath the film. However, observations reported here indicate that microorganisms attack the coating from the surface thereby changing its chemical and physical properties. It has been demonstrated that these effects are generated by metabolites excreted by these organisms.

Natural ventilation of the Paintings Room in the Altamira cave

The Altamira cave (Santillana del Mar, Santander, Spain) is famous for the ceiling of one of its chambers, the Paintings Room, which is decorated with palaeolithic paintings. However, the massive influx of visitors resulted in deterioration of these rupestrian paintings and the cave was closed in 1977 to determine both the causes and the maximum number of visitors that could visit the cave without putting the paintings at risk1–3. The natural ventilation of the Paintings Room is one of the most important factors in formulating the maximum occupational index for visitors to the cave. The emission of carbon dioxide and water vapour by visitors inside the chamber is directly proportional to the number of visitors and the time spent in the room. By ventilating the room, these components should be removed from the air within a short period of time, thus returning the chamber to the prevailing conditions before visitors were allowed in. We report here variations in the 222Rn concentration in the air of the Paintings Room which we use as a quantitative index of the natural ventilation existing in this chamber. We carried out parallel studies of the temperature at different points in the cave and the evolution of the carbon dioxide concentration in the air of the Paintings Room, and hence established the maximum number of people per hour that should be allowed to visit this chamber.

Microbiological degradation of lead-containing pigments in mural paintings

AbstractThe causes of lead-containing pigment conversion in mural paintings of the Church of St John The Divine in Rostov the Great (Yaroslavl region) were studied. The degree of bacterial contamination of the mural paintings was determined. Bacteria were revealed to participate in the conversion of white lead to lead sulphide. It was proved that oxidation of white lead resulting in the formation of brown-coloured lead dioxide is a biogenic process. Microorganisms isolated from the mural paintings are capable of oxidizing, along with white lead, other bivalent lead-containing pigments (massicot, minium). The mechanism of lead oxidation is discussed. Establishment of the fact of bacterial deterioration of mural paintings in the monument under study is a necessary step in the elaboration of methods for its restoration.

Deterioration and preservation of Carolingian and mediaeval mural paintings in the Müstair Convent (Switzerland) Part III: Techniques and materials used and past restorations

Deterioration and preservation of Carolingian and mediaeval mural paintings in the Müstair Convent (Switzerland) Part III: Techniques and materials used and past restorations

Deterioration and preservation of Carolingian and mediaeval mural paintings in the Müstair Convent (Switzerland) Part I: Decay mechanisms and preservation

1 THE PROBLEM Since the wall paintings were restored in 1947-51 accelerated decay has been observed. Three types of deterioration occur: 1 deposition of dirt, 2 detachment of the Romanesque intonaco from its support, 3 decay produced by soluble salts. In order to understand the entire problem, some general features and the main events which have affected the paintings will be mentioned. The Miistair Convent is situated on an alluvial cone at 1250 meters above sea level, in the Miinstertal,a valley issuing to northern Italy at the southeastern border of Switzerland. The alluvial coneis used as farming land. The church is integrated into the building complex of the convent and its southern and eastern side lie next to a public cemetery. The walls, composed of local rubble stones (schists, gneisses and rauhwackes) and lime mortars, still carry the original mediaeval lime plaster on their outside. Only in the basal zones, where they were affected by ground moisture, the plaster has been replaced by mortars containing Portland cement. The walls of the convent show the normal aspect of rising damp up to some three-four meters above the soil. The inner surface of the church is covered by the Carolingian plasters and frescoes, on which the Romanesque ones with their intonaco are superposed. Actually the preserved portions of the Carolingian frescoes are visible on all walls with the exception of the three apses, where the well-preserved Romanesque. paintings are partially superposed. The. main events that have affected the mural paintings are given in Table 1. The most remarkable events are two fires in the eleventh and fifteenth centuries, and the last restoration of

Deterioration and preservation of Carolingian and mediaeval mural paintings in the Müstair Convent (Switzerland) Part II: Materials and rendering of the Carolingian wall paintings

Deterioration and preservation of Carolingian and mediaeval mural paintings in the Müstair Convent (Switzerland) Part II: Materials and rendering of the Carolingian wall paintings

SIX YEAR INTERACTION OF UNDERWATER CLEANING WITH COPPER BASED ANTIFOULING PAINTS ON NAVY SURFACE SHIPS

ABSTRACTThe U.S. Navy implemented a program for the underwater cleaning of Navy surface ships during the fuel crisis of the early seventies. New methods were developed to inspect fouling and paint damage on the hull of a waterborne ship. Underwater photographs of ship bottoms before and after cleaning were used to devise ratings for fouling and paint deterioration. Ratings were employed to evaluate the multiple underwater cleaning of forty‐four surface ships whose hull coatings comprised a copper based vinyl antifouling paint and an epoxy polyamide anticorrosion paint. It was found that the service life of this coating system was shortened by the formation of a thin surface overlay of insoluble cupric compounds. Further, it was found that initial application of more coats of antifouling paint did not lengthen service life. The data indicate that epoxy AC coatings that may have been more uniformly applied are more likely to perform their protective functions better than similar coatings whose uniformity of thickness is not readily controlled. Underwater cleaning does not damage the hull coating when intact on flat and slightly contoured surfaces but may damage the antifouling paint on surface protuberances. Underwater cleaning does not induce blisters but may aggravate corrosion when existing blisters at the coating‐to‐steel interface are ruptured by the cleaning action thus exposing the metal substrate. Underwater cleaning is a viable maintenance procedure and provides an added option to control fouling and extend the service life of the antifouling paint when it reaches a marginal level of performance.

Deterioration and restoration of some Swedish mural paintings

Deterioration and restoration of some Swedish mural paintings

The influence of atmospheric pollutants on the deterioration of mural paintings in the Scrovegni Chapel in Padua

The influence of atmospheric pollutants on the deterioration of mural paintings in the Scrovegni Chapel in Padua

Co-metabolism of paint byAureobasidium pullulans BH-1-ATCC 34621

Although the ability ofAureobasidium pullulans BH-I-ATCC 34621 to cause paint deterioration during its growth on wood has been reported, the mechanism by which paint degradation occurred was unclear. Evidence now indicates that co-metabolism of acrylic, resins in the paint is the cause of paint deterioration byA. pullulans.

Paint Deterioration as a Result of the Growth of Aureobasidium pullulans on Wood

Growth of Aureobasidium was noted on both painted and unpainted wood surfaces but not on painted glass slides, indicating that the source of carbon and energy for growth was not associated with paint components but was probably supplied by the wood. Several aromatic compounds related to aromatic extractives of wood were shown to support growth of this fungus.

The Feasibility of using Thermography to Detect Subsurface Voids in Painted Wooden Panels

Thermography is a technique whereby the construction or condition of objects is studied by means of precisely measuring temperature variations over the surfaces of such objects. Voids within solid structures tend to cause cold or hot spots on the surfaces of these structures as the whole object is heated or cooled slightly. Industrially, thermography is used to detect voids in cast and laminated structures. By studying areas of known voids in test panels, the described research indicated that voids as small as 1/8 in diameter beneath the gessoed surfaces of wooden panels could be resolved with a raster scanning radiometer, the principal instrument used for thermo- graphic studies. Smaller voids were discernible when they were grouped together. Only voids im- mediately beneath the gessoed surfaces of the test panels were detectible. Additional tests indi- cated that areas of simulated cleavage between the wood support and the gesso layers on the test panels could be detected thermographically. Thermography is the technique whereby the structure or condition of objects is studied by means of precisely measuring temperature variations over the surfaces of such objects. Research was undertaken to determine whether thermographic techniques could be ap- plied to the field of art conservation to detect subsurface voids within painted wooden panels. It must be stressed, however, that this research was carried out as a feasibility study with no attempt being made to establish or refine a technique that could be im- mediately applied to the examination of works of art. Blind cleavage and worm tunneling are two manifestations of the deterioration of panel paintings that can be difficult to detect. The term cleavage refers most often to a loss of bond between two paint layers, between a paint layer and the ground layer, or between the ground layer and its support. Blind cleavage is simply a form of cleavage that cannot be de- tected visually. Worm tunneling is the condition affecting panel paintings wherein insects

The change of pH under a paint film due to cathodic protection

The diffusion of OH −-ions and H 2 formed during cathodic protection through a paint film is studied. The diffusion equation is solved for non-stationary conditions and from this the steady state is also derived. It is shown that under usual operating conditions of cathodic protection of ships the stationary state is reached in about 15 days. The danger of paint deterioration through high alkalinity and blistering is found to increase with current density and paint film thickness and with decreasing diffusion coefficient in the paint. For practical calculations a better knowledge of diffusion coefficients in paints is needed.

High temperature resistant paint

Two water-base paints, a regular non-algae and an algae resistant emulsion for decorative purposes, were exposed to artificial, i.e. accelerated, and natural weathering tests and the deterioration compared to that for similar paint applied to exterior walls on multi-unit buildings in Singapore. The artificial weathering test was found not to provide a good representation of actual performance since it only monitors the deterioration due to chemical weathering and not that due to mechanical or biological weathering. The rate of deterioration of paint exposed in natural weathering tests in an industrial region in Singapore was faster than that for paint exposed in-service on multi-unit housing situated in industrial, central or coastal regions in Singapore.

Pullularia as a Cause of Deterioration of Paint and Plastic Surfaces in South Florida

Pullularia as a Cause of Deterioration of Paint and Plastic Surfaces in South Florida

Pullularia as a Cause of Deterioration of Paint and Plastic Surfaces in South Florida

(1950). Pullularia as a Cause of Deterioration of Paint and Plastic Surfaces in South Florida. Mycologia: Vol. 42, No. 3, pp. 432-448.

On the change of refractive index of linseed oil in the process of drying and its effect on the deterioration of oil paintings: A. P. Laurie. Proc. Roy. Soc., A 760

On the change of refractive index of linseed oil in the process of drying and its effect on the deterioration of oil paintings: A. P. Laurie. Proc. Roy. Soc., A 760

On the change of refractive index of linseed oil in the process of drying and its effect on the deterioration of oil paintings

The following paper is the results of experiments undertaken for the information of the Committee appointed by the Royal Academy to investigate the problems affecting the durability of pictures. One of the main defects of the modern picture in oil is that in course of years there is a lowering of tone over the whole of the picture-in contrast not only to the early fifteenth-century pictures in oil, but to many of the later schools of painting, such as the Dutch pictures. As the medium-linseed, walnut or poppy oil-is the same, and as the modern painter uses in many cases the same pigments, and in other cases superior substitutes, the cause of this lowering of tone must be found rather in the unscientific methods of using the materials than in the materials themselves. This view is confirmed by the fact that an examination of modern pictures-by which I mean pictures painted in the last hundred years-reveals marked differences in the extent to which lowering of tone has taken place. The pigments, if properly selected, being permanent under the conditions in a picture gallery, the lowering of tone must be ascribed to the medium. This necessitates a study of the properties of the medium with a view to finding out the reasons why lowering of tone takes place.