Painted Wood Research Articles

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 protection of joinery

The Building Research Station at Garston recently held a one day seminar on Developments in the protection of joinery. The country is currently spending in the region of £90 million a year on the maintenance of exterior joinery, and investigations are in hand to reduce this figure. The Paint Research Association, on behalf of the Building Research Establishment, has recently conducted an investigation into the interactions between wood properties, preservative types, paint systems and conditions of use, to establish the basic criteria for effective, commercial treatments for joinery components.

THE USE OF THE AIRBRASIVE PROCESS FOR CLEANING ETHNOLOGICAL MATERIALS

Ethnological specimens of many different materials can be dry cleaned mechanically by means of a grit-spraying unit. Plain and painted leather, corroded metal, beadwork, metallic embroidery, wood, ivory, bone, basketry, some paper, pottery, shell, some textiles and stone are items which can be cleaned with less disturbance to the surface than is often occasioned by the use of other methods. A specimen constructed of several materials may be cleaned by this one method rather than by several, thereby also avoiding the use of water, solvents or other chemicals. The powdered abrasives used are calcium magnesium carbonate, sodium bicarbonate, glass beads, and several grades of aluminium oxide. Silicone carbide powder is used occasionally for very hard corrosion products on metal.

The Permeability of Moisture through the Paint Film on Wood Surface

The permeability of moisture through the paint film on the wood surface seems to differ from that in the case of an isolated paint film. The main difference is that the swelling of the wooden basis caused by the adsorption of moisture expands the paint on the wood surface, and that subsequently the expansion of the film gives rise to high permeability of moisture through it. In this paper discussion is made on the method to determine the permeability of the paint film on the wood surface on the measurement of the rate of moisture adsorption and desorption of wood coated with four kinds of paint, i.e. aminoalkyd resin paint (AA), nitrocellulose lacquer (NC), polyester resin paint (PE) and polyurethane resin paint (PU).From the adsorption and desorption curves for the painted wood (Fig. 1 and 2), the adsorption and desorption curves for the wooden basis are plotted in Fig. 4 and 5, assuming distribution of moisture within the paint film and the wooden basis which is schematically shown in Fig. 3. The rate of moisture permeation is obtained from inclination of the curves in Fig. 4 and 5, and is plotted against the average moisture content of the wooden basis in Fig. 6. The coefficient of moisture permeation, P, has been calculated, using eq. 5, where Q/tA is the rate of moisture adsorption or desorption from the unit area of the surface, l the thickness of the paint film, ua the equilibrium moisture content for wood at the surrounding humidity, and ub the moisture content of the wooden basis. The coefficient, P, is plotted against the average moisture content of the wooden basis in Fig. 7. The figure shows that the coefficient, P, is slightly increasing with the increasing moisture content of the wooden basis.The comparison of the measured P values with those calculated by eq. 6 from diffusion coefficient, D, density, ρ, and k-value of the isolated paint film shown in Table II indicates that the nature of moisture permeation of the paint film on the wood surface differs from that in the case of an isolated paint film.

Angeli z glasbili v Srednji vasi pri Šenčurju in v Gostečah

Angeli z glasbili v Srednji vasi pri Šenčurju in v Gostečah

A Renaissance Birth Plate

The early Renaissance custom of presenting gifts on a painted wooden tray to the mother of a new-born child is familiar to historians and lovers of art. The trays, however, for all the freshness of their pictures and their aspiring classical themes, soon lost their vogue. With the expansion of the ceramics industry in the sixteenth century and the development of the historiated style of pottery a specially designed set of majolica ware was substituted for the wooden tray.1 The fashion of giving birth-wares persisted until the eighteenth century.

木材塗装の基礎的諸問題

木材塗装の基礎的諸問題

A practical approach to evaluation of the germicidal efficiency of a general purpose military disinfectant.

The bactericidal activity of a general purpose disinfectant consisting of 25% sodium-o-phenylphenolate and 75% sodium-4- and 6-chloro-2-phenylphenolate was evaluated by a simulated in-use, surface-square dilution method. Common floor (asphalt, rubber, and unglazed tiles) and wall (stainless steel tile, ceramic tile, and painted wood) surfaces of various porosities and compositions were selected to simulate actual-use conditions. The method used consisted of inoculating the surfaces of 1-in. square sections of floor and wall covering with a test organism, air-drying the inoculated surface, applying the disinfectant, allowing it to act for 10 min, and recovering the survivors by plating. Confirmatory results of the standard phenol coefficient and use-dilution tests indicated 700 ppm of the disinfectant to be a safe use concentration. The in-use surface-square dilution studies have shown that this is a more than adequate safe concentration for stainless steel, both glazed and unglazed ceramic tile, and nonwaxed surface of asphalt tile. However, concentrations ranging between 2,500 and 6,000 ppm for plastic-fortified rubber tile, 1,500 and 2,000 ppm for waxed asphalt tile, and 2,000 ppm for painted wood were required to achieve 99.9% reduction of either Salmonella choleraesuis or Salmonella schottmuelleri. These results indicate that a disinfectant concentration derived from the Association of Official Agricultural Chemists use-dilution test cannot always be relied upon to provide a dependable index to actual safe use-dilution when a disinfectant is supplied to certain wall or floor surfaces.

Wood Painting

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A Practical Approach to Evaluation of the Germicidal Efficiency of a General Purpose Military Disinfectant

The bactericidal activity of a general purpose disinfectant consisting of 25% sodium-o-phenylphenolate and 75% sodium-4- and 6-chloro-2-phenylphenolate was evaluated by a simulated in-use, surface-square dilution method. Common floor (asphalt, rubber, and unglazed tiles) and wall (stainless steel tile, ceramic tile, and painted wood) surfaces of various porosities and compositions were selected to simulate actual-use conditions. The method used consisted of inoculating the surfaces of 1-in. square sections of floor and wall covering with a test organism, air-drying the inoculated surface, applying the disinfectant, allowing it to act for 10 min, and recovering the survivors by plating. Confirmatory results of the standard phenol coefficient and use-dilution tests indicated 700 ppm of the disinfectant to be a safe use concentration. The in-use surface-square dilution studies have shown that this is a more than adequate safe concentration for stainless steel, both glazed and unglazed ceramic tile, and nonwaxed surface of asphalt tile. However, concentrations ranging between 2,500 and 6,000 ppm for plastic-fortified rubber tile, 1,500 and 2,000 ppm for waxed asphalt tile, and 2,000 ppm for painted wood were required to achieve 99.9% reduction of either Salmonella choleraesuis or Salmonella schottmuelleri. These results indicate that a disinfectant concentration derived from the Association of Official Agricultural Chemists use-dilution test cannot always be relied upon to provide a dependable index to actual safe use-dilution when a disinfectant is supplied to certain wall or floor surfaces.

The prismatic binocular microscope adapted for dermatologic use.

The illustrations show an adaption of a prismatic binocular microscope which has proven itself invaluable in our practice. Head loupes, hand magnifiers, shop and pocket microscopes, and stereobinocular microscopes have been described 1 which have been inadequate or cumbersome resulting in disuse and unpopularity of these instruments. Recent first hand observation of a stereoscopic binocular microscope suggested extremely simple changes which makes it possible to use this fine instrument for dermatologic purposes. The illustration (Fig. 1) shows such a Kern prismatic binocular microscope as it is ordinarily used. The body of the microscope is on a stand ready for observation of material placed on this stand. Various light attachments and arrangements are available for this. By removing the stand and inserting a (painted) wooden ½ in. dowel 6¼ in. long, the instrument becomes an easily hand-held and supported microscope, which rests on its newly created unipod on whatever part of the body the examiner wishes to inspect closely.

Distortion of Polar Diagram Due to Interposition of Wooden Screen in the Vicinity of a VHF Radiator

AbstractA teak wood structure in the proximity of a VHF radiator distorts the polar diagram. Experiments showed that the distortion in the polar diagram is due to the “reflection” and “transmission” properties of teak wood and “absorption” is only of a second order of magnitude. The relationship between the reflection coefficient, frequency, dielectric constant and thickness of wood is determined. The agreement between the theoretically calculated and experimentally observed values of distortion is close. The distortion due to deal wood, perspex, wetting and painting of teak wood was also measured. Laboratory measurement of dielectric constants substantiated the field measurements. The optimum dimensions of a shelter enclosing the radiator for minimum distortion are indicated.

St. Andrew in the Work of Tilmann Riemenschneider

THREE statues of St. Andrew by Tilmann Riemenschneider have hitherto been known: the stone statue in the Wurzburg Cathedral from Riemenschneider's workshop (Figs. 1–2); the lindenwood statue in the altarpiece of the Twelve Apostles in the Kurpfalzische Museum, Heidelberg, which after removal of its coat of paint proved to be a work by the master (Figs. 5–7); and the painted wooden statue that disappeared from the chapel of the Ehehaltenhaus in Wurzburg. The last can be evaluated from the photograph with some probability as also a work of the master (Fig. 3). A fourth statue of St. Andrew by Riemenschneider's hand, an unpainted lindenwood sculpture in the collection of the Samuel H. Kress Foundation, so far unpublished, will be introduced here (Figs. 8–10). Yet before we discuss this statue, we will have to study the other three, since that has never been done with any degree of thoroughness. Through such a comparative study a new insight into Riemenschneider's development during the first decade of the si...

Peterborough, Lincoln, and the Science of Robert Grosseteste: A Study in Thirteenth Century Architecture and Iconography

THE painted ceiling in the nave of Peterborough Cathedral is one of the very few and, for that reason, very important painted wooden ceilings which still remain in Europe from the twelfth and thirteenth centuries. The main part of the nave was built ca. 1155–1175, the west transept ca. 1177–1193 and the west front ca. 1193–1220.1 The ceiling must have been constructed and painted before the dedication of the church in 1238. Cave and Borenius date it “about 1220,”2 but there are reasons for a somewhat later date. At that time the church was not a cathedral but a Benedictine abbey of great importance. Of about the same time as the painted ceiling are some interesting illuminated manuscripts of Peterborough origin, especially psalters, e.g., the Psalter of Robert de Lindeseye in the Society of Antiquaries, London, and a psalter (MS 12) in the Fitzwilliam Museum, Cambridge.3 As early as ca. 1155–1175 the choir screen was also decorated with paintings. There were more than one hundred scenes, all of which have...

The Use of adhesive Agents in DDT Sprays

A previous investigation by the writer established that the minimum deposit of DDT on both cement and old painted wood necessary to ensure complete mortality of bed-bugs 48 hours after spraying was 0·2 mg. per sq. cm., and that the toxicity of both surfaces diminished slowly over a period of six months. The present work has shown that when DDT is applied with an adhesive agent, the minimum deposit of insecticide necessary on these surfaces to yield a similar kill at the same interval after treatment was only 0·06 mg. per sq. cm. The addition of an adhesive agent to a DDT spray thus effects considerable economy in the use of DDT. Campbell and West (1944), investigating the toxicity to houseflies of coumarine resin and DDT dissolved in white spirit, have reported an increase in the efficiency of DDT when sprayed with an adhesive agent. These authors confined their investigation to a resin only and they suggested that the coumarone resin conferred, in a manner not specified, increased insecticidal activity on the DDT. The present work has shown that relatively small doses of DDT are highly effective in the presence of at least three dissimilar adhesive agents. It is possible, therefore, that instead of increasing the activity of DDT, the agent merely blocks the minute pores of the treated surface, and by minimising absorption of the solution, increases the amount of DDT available to the insect. Alternatively, the adhesive agent may have some affinity for substances on the surface of the bug's tarsi and so assist transfer of DDT from the sprayed surface to the insect.The residual toxicity of cement treated with DDT and an adhesive agent, like that of a similar surface treated with DDT alone, diminished slowly. The toxicity of painted wood, on the other hand, treated with doses of DDT and adhesive agent ranging from 0·005 to 0·02 mg. per sq. cm., decreased within one month, irrespective of the adhesive agent used. This fall in toxicity is puzzling, particularly in view of the fact that no such decrease occurred when the surface was treated with a heavier deposit of DDT and adhesive agent, namely 0·06 mg. of each per sq. cm. This latter observation seems to preclude a possible interference with the efficiency of DDT by a slow interaction of the paint constituents and the adhesive agent.The application of these adhesive agents, even in relatively high doses, failed to prevent the removal of DDT from a smooth surface by repeated washing and rubbing; furthermore, an increase in the deposit of adhesive agent does not markedly increase the insecticidal efficiency of a given deposit of DDT.

A Byzantine Reliquary of the True Cross from the Sancta Sanctorum

The small painted wooden reliquary of the True Cross found among the objects in the Sancta Sanctorum early in the twentieth century, after centuries of being hidden, is one of the few Byzantine icons which have come down to us.2 It is now in the Museo Cristiano of the Vatican Library. The upper face of the lid (Fig. 1) has represented upon it a Crucifixion which is motivated by the fact that the box is a reliquary of the Holy Cross. The most striking motif is the Virgin embracing the suppedaneum, a theme which does not appear elsewhere in Byzantine art, so far as I know. It may be found in Italian art3 of the thirteenth century, and widely spread throughout Europe at a later date, as an expression of pathos.

Studies in the Painting of Wood

Studies in the Painting of Wood

New Books Studies in the Painting of Wood I—Influence of Wood Structure on Paint Behaviour

New Books Studies in the Painting of Wood I—Influence of Wood Structure on Paint Behaviour

Studies in the Painting of Wood

Studies in the Painting of Wood