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1.
《文物保护研究》2013,58(1):15-32
Abstract

An investigation for light exposure on pigments in low-oxygen environments (in the range 0–5% oxygen) was conducted using a purpose-built automated microfadometer for a large sample set including multiple samples of traditional watercolour pigments from nineteenth-century and twentieth-century sources, selected for concerns over their stability in anoxia. The pigments were prepared for usage in watercolour painting: ground and mixed in gum Arabic and applied to historically accurate gelatine glue-sized cotton and linen-based papers. Anoxia benefited many colorants and no colorant fared worse in anoxia than in air, with the exception of Prussian blue and Prussian green (which contains Prussian blue). A Prussian blue sampled from the studio materials of J.M.W. Turner (1775 ? 1851) was microfaded in different environments (normal air (20.9% oxygen) 0, 1, 2, 3.5, or 5% oxygen in nitrogen) and the subsequent dark behaviour was measured. The behaviour of the sample (in normal air, anoxia, and 5% oxygen in nitrogen) proved to be consistent with the 55 separately sourced Prussian blue samples. When exposed to light in 5% oxygen in nitrogen, Prussian blue demonstrated the same light stability as in air (at approximately 21°C and 1 atmosphere). Storage in 5% oxygen is proposed for ‘anoxic’ display of paper-based artworks that might contain Prussian blue, to protect this material while reducing light-induced damage to other components of a watercolour, including organic colorants and the paper support.  相似文献   

2.
《文物保护研究》2013,58(3):201-210
Abstract

Thirty artists' colors have been exposed for 12weeks to 120ppb of formaldehyde in purified air as well as to purified air alone (control experiment). The exposure was carried out in the dark at ambient temperature (19 ± 2°C) and humidity (RH 44–52%). Color change (?E) was measured using a reflectance color analyzer after one, two, three, four, six, eight, 11 and 12 weeks of exposure. Color parameters (x, y, X, Y, Z, L*, a*, b* and ?E)"were also calculated from the 380–700nm spectra, recorded with a reflectance spectrophotometer, of unexposed colorants and of colorants exposed for 12 weeks to purified air and to formaldehyde. Regression analysis of the two data sets indicated that the color changes measured by these two methods were in excellent agreement (nearunity slopes, with correlation coefficients > 0.99). Exposure to either formaldehyde or pure air on watercolor paper resulted in little or no color change for all the colorants tested, including inorganic colorants, alizarin lakes, quinacridones, triphenyl methanes, indigo derivatives, arylamides and natural colorants such as curcumin. Formaldehyde, which is ubiquitous in indoor air, including museum air, does not appear to be a major threat to colorants in museum collections.  相似文献   

3.
《文物保护研究》2013,58(4):267-280
Abstract

This project examines the lightfastness of prints created with the most commonly used digital technologies (inkjet, color electrophotography, dye sublimation and digital press) along with prints created using traditional technologies (color photography, black-and-white electrophotography and offset lithography). The inclusion of traditional prints provides benchmarks for collection care professionals to better gauge the significance of the results. In this study, prints were subjected to two types of lighting used independently to simulate daylight through window glass and artificial indoor illumination. Five aspects of light damage were assessed: fade in the mid-tone neutral, fade in the darkest neutral tone, paper yellowing, changes in paper gloss and text readability. In general, digital prints were less sensitive to light than traditional prints; but each digital printing technology produced at least one sample that performed worse than its traditional benchmark in at least one of the aspects of light damage studied. Therefore, it is recommended that cultural heritage institutions strive to provide the most benign environment possible, taking display practices currently in use for traditional prints as a minimum starting point for the care of digital prints. Close monitoring for signs of change is also recommended.  相似文献   

4.
ABSTRACT

Twentieth century paints often contain titanium dioxide and zinc oxide based white pigments that can range from photostable to highly photocatalytic. Photocatalytic pigments can cause the degradation of paint upon UV exposure, whereas photostable pigments may be benign or can protect paintings from degradation. Hence, knowing whether or not a pigment is photocatalytic is of high importance for risk assessment and the subsequent decision making process concerning storage and exposure conditions of objects. Here we present a proof of principle, focused on titanium white paints, for an easy-to-use and low-tech application of a commercial photocatalytic activity indicator ink (PAII) on embedded paint samples or cross sections. This test determines, qualitatively, if a photocatalytic pigment is present in a white paint sample. The PAII paint sample staining application shows an obvious color change, within five minutes of UV irradiation, for paint samples containing photocatalytic pigments. A microscope with a camera and a UV source are the only necessary equipment for the application of this method. A quantitative image processing protocol is also proposed as an extension of the staining method by applying open source software analysis to measure the color change using photographs. The test was evaluated on reference paints with well-characterized pigments and applied on samples from modern paintings by Piet Mondriaan, Robert Ryman, and Lucebert, indicating the presence of harmful photocatalytic pigments in these cases. The novel application of a commercial ink on paint samples offers a simple test, not just for assessment of photocatalytic activity of titanium white pigments, but which may in future be applied for the detection of photoactive forms of zinc white and other potentially harmful semiconductor pigments in art objects.  相似文献   

5.
ABSTRACT

Lighting a cultural heritage artifact requires balancing visual perception with preventive conservation, by providing the best lighting (in terms of spectral distribution and quantity) to enable the viewer to appreciate details and color, while limiting photo-induced degradation. The paper outlines the methodology applied by a multi-disciplinary team while lighting the Shroud of Turin at its last public exhibition in 2015. The methodology considered the special requirements of the Shroud, including exposure to ultraviolet light, while providing appropriate display conditions that would meet audience expectations. The desired appearance (readability of the body image and color) was defined with the help of Shroud researchers and confirmed by subjective tests, while appropriate light levels for preservation were set in agreement with standard requirements and using knowledge of the degradation of linen in visible and UV light. The installation provided a controlled environment and a managed visitor route to the Shroud, assuring excellent perception of both details and color, with the lowest illuminance level about 15?lx.  相似文献   

6.
The impact of the spectral composition of light on the discoloration of paint pigments has been investigated for the case of lead chromate sulfate, an unstable yellow pigment used by Vincent van Gogh and other painters. With LEDification, museum lighting is moving from using halogen to LED lamps. LED light sources have a significantly different spectral composition than halogen lamps. To understand the impact of these differences on pigment stability, the wavelength dependence of pigment discoloration was determined. Contrary to the expectation that lower wavelength photons induce more damage than higher wavelength ones, UV (394?nm), blue, and cyan light all lead to similar levels of discoloration of a pigment for the same level of radiant power. By understanding this wavelength dependence, it becomes possible to create white light LED lamps with a spectral composition tuned to minimize the degradation effect. An existing LED solution with a modified emission indeed resulted in 30% less color change in the experiment than halogen. Furthermore, a method is proposed to optimize the LED spectra by tuning to the properties of each specific artifact. Simulations show that this can reduce the damage of the light source by 45% in specific cases.  相似文献   

7.
《文物保护研究》2013,58(1):22-26
Abstract

Very small paint samples from Cosimo Tura's ‘The Annunciation with Saint Francis and Saint Louis of Toulouse’ were submitted to amino acid analysis in order to determine the nature of the binding media. The four panels appeared to have been painted with egg tempera, and showed extensive localized deterioration in the blue areas but not in the other coloured areas. Following the Picotag method, the samples were hydrolyzed in an acid vapor, derivatized with iso-thiocyanatobenzene, and analyzed using reversed phase high pressure liquid chromatography (HPLC). Amino acid analysis demonstrated that the red and brown areas were painted using egg yolk as the binding medium, while the blue areas were painted with animal-skin glue (distemper). Analysis of the green paint indicated a mixture of egg yolk and glue. The use of these techniques makes it possible to identify proteinaceous materials in art objects from samples in the microgram range.  相似文献   

8.
Background:With the mandate to review all available literature in the study''s inclusion parameters, systematic review projects are likely to require full-text access to a significant number of articles that are not available in a library''s collection, thereby necessitating ordering content via interlibrary loan (ILL). The aim of this study is to understand what effect a systematic review service has on the copyright royalty fees accompanying ILL requests at an academic health sciences library.Case Presentation:The library created a custom report using ILLiad data to look specifically at 2018 ILL borrowing requests that were known to be part of systematic reviews. This subset of borrowing activity was then analyzed to determine its impact on the library''s copyright royalty expenditures for the year. In 2018, copyright eligible borrowing requests that were known to be part of systematic reviews represented only approximately 5% of total filled requests that involved copyright eligible borrowing. However, these systematic review requests directly or indirectly caused approximately 10% of all the Spencer S. Eccles Library copyright royalty expenditures for 2018 requests.Conclusion:Based on the sample data set, the library''s copyright royalty expenditures did increase, but the overall financial impact was modest.  相似文献   

9.
This study aims to measure the mechanical strength of chemically degraded wood samples and compare the values obtained with fresh wood and degraded wood treated with sugars. The mechanical strength of chemically degraded waterlogged wood samples was determined using a three-point bending system to generate load-deflection curves and subsequently calculate the modulus of elasticity and load to failure longitudinally. The values obtained allow us to compare the mechanical properties of white birch wood samples that were air dried after treatment with 60% w/v solutions of sucrose, trehalose, or sucralose. In addition, the same parameters were measured for fresh white birch wood samples and chemically degraded samples that were allowed to air dry without treatment. Fresh white birch was found to have a longitudinal modulus of elasticity of 11.5?GPa whereas this value decreased by 70% when the wood was degraded. Treatment with sugars increased the measured values of modulus of elasticity up to 36.9?GPa, a substantially higher value than for fresh wood. These data indicate that non-reducing sugars could be useful alternatives to polyethylene glycol for the conservation of waterlogged archaeological wood.  相似文献   

10.
《文物保护研究》2013,58(4):257-266
Abstract

A study of the accelerated light fading behavior of face-mounted color photographic materials has shown that alterations on the surface of the materials influence their fading characteristics. With the help of spectral density measurements it became apparent that the application of materials such as silicone rubber, adhesive film and acrylic sheeting, but also laminating films, onto the surface of the prints accelerated the degradation of the colorants, especially the yellow dye, in chromogenic materials. In the case of silver dye bleach materials, however, the opposite effect was observed. The influence of the material combination on the stability of face mounted color photographic prints was demonstrated to vary considerably. In order to better assess the inherent damage potential of the materials themselves, these were examined by means of instrumental analysis and measurements of pollutant gasses. Besides off-gassing compounds such as acetic acid and changes in pH caused by aging of the adhesive, face-mounting with a rigid plastic sheet (acrylic glazing) also affected the respective fading behavior of the various materials that were tested.  相似文献   

11.
《文物保护研究》2013,58(3):212-222
Abstract

It is still unclear why some of the blue enamel on sixteenth- and seventeenth-century stained window glass is flaking off, while enamel layers with other colours are still in relatively good condition. In order to obtain a better understanding of this conservation problem, 31 historical recipes used for the fabrication of blue enamel were compared with results from the chemical analysis of 25 historic samples. The chemical composition and the microstructure of the enamels were analysed in cross-section by means of electron probe microanalysis (EPMA). This study demonstrated that the variation in chemical composition of the samples can be explained by the use of the wide range of recipes existing at that time. Although this study gave an insight into the composition, heterogeneity and use of colouring substances, no clear relation could be found between the parameters analysed and the deterioration rate of the blue enamel paint layer.  相似文献   

12.
《文物保护研究》2013,58(4):265-273
Abstract

This paper reports on the results of experiments to test for visual changes to paint systems after biocidal treatments, using a statistical binary procedure. Four biocides were selected, two of which are fungicides—a quaternary ammoniumorganotin mixture (BioMet 66®)in distilled water and an orthophenylphenol (Lysol®) in a spray— and two of which are fumigants—sulfuryl fluoride (SO2F6), a gas (Vikane®), and nitrogen gas (N2) (as an anoxant). The procedure used to assess the effect of the biocidal treatments was a random field visual scoring regimen by two paintings conservators. The tests were conducted on 30 combinations of linen, rabbitskin glue size, lead white oil ground and oil-based paints. The visual assessment procedure provided information on color change, gloss change, blanching, topography change and precipitation. The results indicated that Vikane adversely affected 10 of 11 pigment systems; Lysol adversely affected six of 11 pigment systems; BioMet 66 had a minor effect on four of 11 pigment systems; and nitrogen had no visible effect on any sample. The visual technique provided a quick and broad method for assessment of non-subtile visual changes.  相似文献   

13.
《Public Services Quarterly》2013,9(2-3):167-190
  相似文献   

14.
ABSTRACT

The surface texture of a stone represents a sensitive parameter in evaluating its conservation state. In monuments and sculptures, in fact, external agents continuously alter the appearance of stones, determining peculiar weathering patterns and modifying properties such as retention of water and particles, interaction with light, color, and finishing. The application of protective coatings also determines changes in surface appearance of a stone, usually evaluated and monitored by color change tests. Surface metrology methods offer the possibility to quantify these changes, evaluating the impact of external agents (natural, i.e. weathering, and artificially, i.e. protective coatings) on natural stones. In this research, we demonstrate the potential of surface areal measurements in describing the evolution of weathering processes and the effects of protective treatments on porous stone materials. The obtained results suggest that the extent of the modifications is related to the scale of observation (small- vs. large-scale undulations, i.e. roughness and waviness, respectively), with an overall increase of surface roughness as the weathering proceeds. Unexpectedly, coatings based on nanoparticle dispersions increase the topographic height parameters, due to the absence of a homogeneous film.  相似文献   

15.
Abstract Over the last 10 to 15 years, zoos and aquariums have set out to influence visitors' conservation‐related knowledge, attitudes, affect, and behavior. In 2000, the Institute for Learning Innovation collaborated with Disney's Animal Kingdom (DAK) on a comprehensive baseline study conducted to assess the outcomes of a DAK experience on visitors in four areas: knowledge, attitudes, affect, and behavior. This article describes one aspect of the comprehensive study: an investigation of the long‐term (two‐to‐three‐month) impact of a visit to Conservation Station at Disney's Animal Kingdom on visitors' intended conservation action. The study used a behavior change model from the health arena: the Prochaska Model of Behavioral Change. The model proved helpful but had some drawbacks, suggesting the need to develop a more sensitive change model. The implications of this study could assist institutions in thinking about what audiences or messages to emphasize in order to influence behavior.  相似文献   

16.
《文物保护研究》2013,58(3):195-208
Abstract

Pyrolysis–gas chromatography was applied to the characterization of synthetic organic pigments. On pyrolysis, azo pigments and phthalocyanine blue yield characteristic fragments. These pyrolysis products were identified, and the mechanism of decomposition was studied. In the case of paint samples, the main pyrolysis products derive from the medium, although the presence of additional peaks enables azo pigments and phthalocyanine blue to be characterized. Some examples of the analysis of artists' paints are given and the peaks are identified. The main limitation of this technique is that it is impossible to detect chemically and thermally stable pigments, or inorganic components.  相似文献   

17.
ABSTRACT

Chalconatronite, Na2[Cu(CO3)]2·3H2O, is formed as a corrosion product when copper alloys are exposed to sodium carbonate solutions in the air. This also happens when metals come into contact with corroding soda glass which forms alkaline surface films in reaction with humidity from clean air. More often, substantial amounts of formaldehyde are present indoors which react to formate via the Cannizzarro reaction and accumulate over time in the films. Twenty cases of chalconatronite (including two mentioned in the literature) are reported as occurring on heritage objects with glass in contact with copper alloys: Baroque reliquaries with set glass gems, enamel on metal (sixteenth century and a modern replica of intentionally unstable composition), Christmas tree glass baubles with wires, glass buttons with metal shanks, a glass figure with a wire support, miners’ lamps, and a glass framed daguerreotype. These confirmed identifications might help conservators in investigating similar cases to shed more light on the formation conditions.  相似文献   

18.
高校图书馆内部环境对学生心理影响及优化途径   总被引：26，自引：0，他引：26  
从环境心理学角度出发,分析了高校图书馆光、声环境,色彩及室内空气质量对学生心理因素的影响,进而从环境设计视角,探讨优化图书馆建筑内环境的途径。  相似文献   

19.
On Collection Size and Retrieval Effectiveness   总被引：3，自引：0，他引：3  
The relationship between collection size and retrieval effectiveness is particularly important in the context of Web search. We investigate it first analytically and then experimentally, using samples and subsets of test collections. Different retrieval systems vary in how the score assigned to an individual document in a sample collection relates to the score it receives in the full collection; we identify four cases.We apply signal detection (SD) theory to retrieval from samples, taking into account the four cases and using a variety of shapes for relevant and irrelevant distributions. We note that the SD model subsumes several earlier hypotheses about the causes of the decreased precision in samples. We also discuss other models which contribute to an understanding of the phenomenon, particularly relating to the effects of discreteness. Different models provide complementary insights.Extensive use is made of test data, some from official submissions to the TREC-6 VLC track and some new, to illustrate the effects and test hypotheses. We empirically confirm predictions, based on SD theory, that P@n should decline when moving to a sample collection and that average precision and R-precision should remain constant. SD theory suggests the use of recall-fallout plots as operating characteristic (OC) curves. We plot OC curves of this type for a real retrieval system and query set and show that curves for sample collections are similar but not identical to the curve for the full collection.  相似文献   

20.
ABSTRACT

Adsorbent materials can be used for the removal of organic acids from air in storage rooms with heritage collections. The organic acid removal efficiency of two commercially available activated carbon air-filters were tested in situ in two unoccupied stores with densely packed collections. One filter was designed for outdoor type pollutants (Filter A), while the other was designed for organic acids in indoor air (Filter B). Furthermore, the acetic acid removal efficiency of a desiccant silica gel rotor used for dehumidification was measured in a laboratory at different relative humidity levels. Finally, passive removal of acetic acid by silica gel and unfired clay brick were tested in a chamber, and for clay brick at room level as well. Filter B had the highest removal efficiency. The removal efficiency of both filter types depended on the airflow and the filter performance varied considerably in situ from the values reported from standard laboratory tests. Increasing the filter airflow reduced the removal efficiency from 77% and down to 7% for Filter A, and from 92% to 24% for Filter B. There was almost no effect of active air filtration on the concentration of organic acids when this was measured in the middle and in the corner of the storage rooms away from the ventilation inlets. The desiccant dehumidifier removed 98–100% of the acetic acid from the air, independently of the relative humidity. The desiccant rotor will, however, only be running when there is a need for dehumidification and as a result will only periodically remove pollutants. The high acid removal efficiency by dry silica gel was furthermore demonstrated in a chamber test. A clay brick wall in a test room established a concentration gradient across the room and reduced the concentration of organic acids by 56% compared to close to the emission source.  相似文献   

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