Painted Surfaces Research Articles

Methodology & Resources: New Findings from the National Gallery of Art

The findings of the recent comprehensive technical study (2020–2022) of all four works by or attributed to Vermeer at the National Gallery of Art, Washington, are presented in three articles in this issue. This section offers guidance on using the JHNA image viewers and expands on the brief technical overviews in the articles with additional detail on the analytical methods used. For those who have not previously used such documents, we offer suggestions on how to interpret technical evidence. For those who regularly use such evidence in their research, the specific operating parameters of each method can be found in the endnotes of each section below. Whereas prior studies mainly relied on microanalysis of paint samples and magnified examination of the painted surface with a stereomicroscope, this study also used extensive analysis based on non-invasive chemical imaging spectroscopy, the results of which are presented in the form of images and maps, rather than graphs, making them accessible to a wider audience.

Preparation of Resin-Coated Waterborne Coating Microcapsules and Its Effect on the Properties of Waterborne Coating for Wood Surfaces

In this paper, the related experiments were carried out on microcapsules, with the aim of making the prepolymer react with the core emulsion by in situ polymerization using urea–formaldehyde resin as the wall material and waterborne acrylic wood coating as the core material. The prepared microcapsules were added to the waterborne acrylic wood coating and brushed on wood boards. Then, the gloss, hardness, adhesion, impact resistance and color difference were compared with paint surfaces without microcapsules. When the ratio of the microcapsule core-to-wall material was different from the increase in microcapsule content, the gloss of the coating decreased continuously; the decreasing range was basically the same, and the gloss values of the three core-wall ratio microcapsules were rather similar. With the increase in microcapsule content, the impact resistance of the coating first increased and then decreased. With the increase in microcapsule content, the color difference of the coating also increased continuously. The color difference of the coating with a microcapsule core-wall ratio of 0.67 changed the least, and the coating performance was good. When the core-wall ratio of the microcapsules was 0.67, and the proportion of microcapsules in the paint was 7.0%, the comprehensive properties of this coating were good. This research is of great significance to the future protection and development of wood.

Robot-assisted laser ablation for 3D surfaces. Application for paint removal with ultrashort pulse laser

In this work, a robot-assisted laser cleaning system is presented that allows the automatic processing of 3D objects with arbitrary geometry. The system is based on the integration of a femtosecond pulse laser with a 6-degree-of-freedom (6 DOF) robotic arm and a laser profilometer to capture the geometry of the workpiece. An automatic procedure is performed to generate cleaning paths over the geometry, which is finally targeted by a laser source by means of the prescribed robot motion; thus, both the working distance and the normal incidence of the laser beam are kept fixed for each point on the surface. The manipulator allows displacements and changes of orientation of the object to be processed following the programmed paths in a full 3D solution. The system was tested by performing the cleaning over different curved painted metal surfaces. Experimental results show the effectiveness of the proposed method that improves the efficiency of the automatic laser cleaning of 3D objects and further promotes its application to other ablation processes.

Light scattering model for small space debris particles

We have developed a scattering model allowing to study interaction of light with particles populating the near-Earth environment: satellite explosion remnants, collisional debris, particles detached from peeling paint surfaces, and ejecta resulting from micrometeorite bombardment. In its present configuration the model accounts for rough needles, grains, and plates as primary shape elements. More complex shapes are built upon combining them.The model is compared and validated against laboratory measurements. The studied samples include a set of space debris analogue samples obtained from the controlled MIRAD (Microparticle impact related attitude disturbances) experiment that collided solar cell panels with a projectile. The resulting samples are mostly carbon needles and curved aluminium sheets. We have both measured and modelled the scattering of light from a set of these samples.The model agrees rather well with the measurements. The shape and orientation of the particles are found to be the main contributor in how light is scattered, whereas the material dependence shows a weaker trend. Large amount of data with varying viewing and illumination angles are needed to allow for inversion of the target characteristics.The experimental results exploited in our study have significantly aided the model development. In the future, this work can be expanded to a real-mode in-orbit scattering model that can be utilised in Earth system and/or astronomical observations and space mission concept designs. Additional measurements with larger variety of samples and their expanded size range are required to extend and solidify the model for the full range of populations representing space particles.

A novel method for assessing haze in the visual appearance of bright-annealed AISI 430 ferritic stainless steel

In this paper, a novel method for evaluating the degree of haze on the surface of bright-finish AISI 430 ferritic stainless steels is presented. Haze is an undesirable effect that typically manifests as a loss of brightness and specularity on the steel surface. Visual inspections are used for quality control, with the tested product compared to reference surfaces. This method is strongly influenced by the visual acuity of the operator and the lighting conditions of the production line. In addition, the use of portable glossmeters does not provide a good correlation between the degree of cloudiness and the parameters of the instrument, which are typically defined for evaluating painted surfaces. Furthermore, neither method allows for a quantification of the degree of haze in the stainless steel, only an acceptance or rejection evaluation. The method described in this paper attempts to overcome these limitations by analyzing gray-level histograms of images of high-contrast Ronchi-type patterns reflected on the steel surfaces. The results show that this method is sensitive to haze and allows the degree of haze on the surfaces of these industrial products to be quantified.

Environmental Pressures at Dirre Sheikh Hussein Sanctuary

Dirre Sheikh Hussein is a religious complex in Ethiopia that dates from the 12th century or earlier. An important focus for pilgrimage, it lies in an isolated part of Oromia State on poorly drained semi-arid lowlands. Significant architecturally and culturally, recent expansion and refurbishment of the major buildings led to structural issues, though these are now largely overcome through consolidation of the prayer hall roof, laying a stone walkway, digging drainage ditches etc. Current deterioration of the buildings can be seen as: (i) fading of colours, (ii) cracks in walls, roofs, and festive places, (iii) deposits of sand around walls and (iv) staining and drainage marks on the white painted surfaces. Heavy falls of rain overwhelm drainage and overfill storage pools. Meteorological observations are infrequent locally, so those made some 70–100 km away were used, along with regridded historical data, reanalysis and CMIP6 projections. These revealed increases in temperature, precipitation and humidity, and provided indications of long-term climate pressures at the site. Changing patterns of future precipitation, particularly heavy rain, may threaten the site. The relative humidity changes are small, though an increasing Scheffer index suggests potentially enhanced wood decay. Changes in soil moisture have the potential to disrupt the foundations. Very hot days may become a problem for the two annual celebrations at the site.

A multi-analytical approach for the characterization of materials, manufacturing process and damage mechanisms of wall paintings in Samye Temple, Tibet

This research focuses on the multi-technique characterization and identification of degradation mechanisms of the wall paintings at the Samye Temple in Tibet, which is considered the first built temple of Tibetan Buddhism with an enormous cultural significance to the region. Wall painting general stratigraphy was thoroughly analyzed by Optical Microscopy (OM), Scanning Electron Microscopy – Energy Dispersive X-Ray Spectroscopy (SEM-EDS) and X-ray Powder Diffraction (XRD). Results reveal a clear sequence, from the interior to the surface, consisting on an adobe wall support, a coarse mud plaster, a fine mud plaster, a white ground layer, a surface paint layer, and a coating layer. The identification of natural and/or synthetic pigments and possible re-painted areas was analyzed by polarized light microscope and SEM-EDS, and subsequently studied using Raman spectroscopy. Results reveal the mineral pigments include red cinnabar (HgS) and red lead (Pb3O4), blue azurite (Cu3(CO3)2(OH)2), green malachite (Cu2CO3(OH)2), yellow orpiment (As2S3), and a gold layer (gold powder). White and black pigments are magnesite (MgCO3) and carbon, respectively. Additionally, the external surface coating varnish found on the top of the paint layer was also analyzed by Transmission Fourier Transform Infrared Spectroscopy with Attenuated Total Reflectance mode (FTIR-ATR), Proton Nuclear Magnetic Resonance (H1 NMR), Thermogravimetric analysis (TG), Mass Spectrometry (MS) and SEM-EDX analysis. Results show main components of this coating include acrylates and, possibly, silanes, revealing a recent conservation intervention activity. The hydric expansion/contraction of clay minerals in the adobe support and mud plaster layers and the rigid and impervious acrylate coating layer could have accelerated the deterioration and be the responsible for the development of cracks both at the interface of the different support layer and normal to the wall painting surface, resulting in massive losses. These findings are relevant to better understand the traditional manufacturing process of historic wall paintings in Tibet, which is not fully understood yet, and serve to further conservation activities of this historically rich temple.

Surface Metrology Based on Scanning Conoscopic Holography for In Situ and In-Process Monitoring of Microtexture in Paintings.

In the field of engineering, surface metrology is a valuable tool codified by international standards that enables the quantitative study of small-scale surface features. However, it is not recognized as a resource in the field of cultural heritage. Motivated by this fact, in this work, we demonstrate the use and the usefulness of surface metrology based on scanning conoscopic holography for monitoring treatments on the Venetian masterpiece by Tintoretto St. Martial in Glory with the Saints Peter and Paul. We carried out in situ and in-process monitoring of the painting microtexture during an experimental, innovative laser–chemical treatment, and we performed a statistical analysis based on ISO areal field parameters. A wide and in-band roughness analysis through the complementary use of amplitude, spatial, and hybrid parameters confirmed the noninvasive nature of the whole treatment on the painting surface topography, giving us the chance to review and critically discuss the use of these parameters in a real case in heritage science.

Transmission Mysteries: Art and Technophilia

Transmission Mysteries: Art and Technophilia

A Case Study on First Time Quality Feature Investigation for an Automotive Paint Shop

In today’s highly automated automotive paint shops, production equipment such as robots and conveyors controlled by various sensors and programmable logic controllers (PLCs) are widely used to coat vehicle bodies-in-white. A high-volume automotive paint line typically consists of miles of conveyor lines and dozens of sealing and painting robots equipped with hundreds of sensors and PLCs. It takes a body-in-white several hours to travel on conveyor tracks to complete the painting process. Throughout this process, thousands of process variables are monitored and collected from sensors and devices that control the automatic equipment. When a vehicle is painted, process variables and associated outcomes are collected in a centralized database called the Painted Surface Performance Management (PSPM) system. This database contains a complete history of each painted vehicle and its corresponding quality inspection results. In this work, machine learning (ML) models are used to select a list of the most important features that may affect the outcomes of the painted vehicles. However, this list needs to go through additional steps of feature investigations to validate true causal relationships between the selected features and the target variables. Once this step is completed, the selected features can then be used to target operational first time quality (FTQ) of products through use of such ML models to predict FTQ outcomes. An automotive paint shop data from 2020 to early 2021 was used to conduct a case study to demonstrate the process of feature investigation. Observations and recommendations from the ML model analysis are summarized for improvement.

Submerged surfaces exposed to marine biofouling – Experimental investigation of cleaning parameters effectiveness

Physical cleaning, an important factor in maintaining ships' hulls free from biofouling, can help to prolong the lifetime of fouling-control coating systems. This study investigated how mechanical cleaning parameters (cleaning force, duration and frequency) affected antifouling coatings' performance including fouling resistance property and cleaning efficiency using a specially designed manual cleaning system. Meanwhile, coating surface conditions, including visual appearance condition, roughness, contact angle were evaluated in detail. Biocide release rates of copper-based soluble antifouling paint (Cu-AF) under different cleaning conditions were also assessed by Scanning Electron Microscopy - Energy Dispersive X-ray (SEM-EDX) analysis. Results from the field testing in Danish sea area showed that cleaning frequency affected more than cleaning force and duration on antifouling coating performance. Algae glue attachment increased the difficulty in the cleaning of non-coated acrylic surface (A-BS) and fluorine-based copper free insoluble antifouling paint (F-AF). For Cu-AF coated panels, no significant mechanical damages were observed after cleaning. For F-AF, scratches formed on the coating surface after cleaning were more related to cleaning force and cleaning frequency. The biocide release rates of Cu-AF under various cleaning condition were between 15.7 and 24.6 μg Cu cm−2 day−1. Gentle cleaning of Cu-AF with proper frequency has little influence on the copper release rate. This study provides guidance on cleaning strategies for antifouling coatings.

Gas-Phase Nitrous Acid (HONO) Is Controlled by Surface Interactions of Adsorbed Nitrite (NO2-) on Common Indoor Material Surfaces.

Nitrous acid (HONO) is a household pollutant exhibiting adverse health effects and a major source of indoor OH radicals under a variety of lighting conditions. The present study focuses on gas-phase HONO and condensed-phase nitrite and nitrate formation on indoor surface thin films following heterogeneous hydrolysis of NO2, in the presence and absence of light, and nitrate (NO3–) photochemistry. These thin films are composed of common building materials including zeolite, kaolinite, painted walls, and cement. Gas-phase HONO is measured using an incoherent broadband cavity-enhanced ultraviolet absorption spectrometer (IBBCEAS), whereby condensed-phase products, adsorbed nitrite and nitrate, are quantified using ion chromatography. All of the surface materials used in this study can store nitrogen oxides as nitrate, but only thin films of zeolite and cement can act as condensed-phase nitrite reservoirs. For both the photo-enhanced heterogeneous hydrolysis of NO2 and nitrate photochemistry, the amount of HONO produced depends on the material surface. For zeolite and cement, little HONO is produced, whereas HONO is the major product from kaolinite and painted wall surfaces. An important result of this study is that surface interactions of adsorbed nitrite are key to HONO formation, and the stronger the interaction of nitrite with the surface, the less gas-phase HONO produced.

Development of poly(butyl acrylate‐co‐oleic acid) as biobased polymeric dispersant and its application in preparation of pigment concentrate

AbstractIt is highly desirable to develop bio‐based products using sustainable materials and reduce dependence on petrochemicals. There are various reports on the use of sustainable materials in the synthesis of polymer resins, but research on the use of sustainable materials in development of coating additives such as polymeric dispersant is significantly lacking. Objective of this work is to produce fatty acid‐based polymeric dispersant using oleic acid in combination with butyl acrylate. The performance of the fatty acid‐based polymeric dispersant was benchmarked against commercially available and petrochemical‐based polymeric dispersant. The dispersants produced were characterized using spectroscopies (1H‐NMR and FTIR), thermal analyses (thermogravimetric analysis and differential scanning calorimetry), and molecular weight analysis. Application test was conducted to evaluate the effectiveness of the polymeric dispersant in titania pigment concentrate formulation which was tinted in nitrocellulose clear coating. Properties such as viscosity, fineness, gloss, optical properties, and storage stability were evaluated, and the result obtained shows that fatty acid‐based polymeric dispersant could disperse titania efficiently and produced coatings with good optical properties and excellent gloss retention. The carboxyl group from the incorporated fatty acid served as excellent pigment anchoring group, facilitating good orientation of dispersant on the pigment surface and promote excellent stability.

Preparation of Stable Superhydrophobic Coatings on a Paint Surface with the Use of Laser Treatment Followed by Hydrophobizer Deposition

Preparation of Stable Superhydrophobic Coatings on a Paint Surface with the Use of Laser Treatment Followed by Hydrophobizer Deposition

Nanocracks in nature and industry.

Nanocracks in nature and industry.

Effects of Natural Weathering on the Performance of High Solar Reflective Index Paint Surfaces Exposed in Harsh Climatic Conditions of United Arab Emirates

The solar reflective index (SRI) is one of the important parameters in the analysis of a building’s energy and thermal performance, especially for “cool” reflective paints or coatings and also for cool roof membranes. However, there exists less information on the typical performance of the cool materials exposed for long term in the Middle East and more specifically in the United Arab Emirates (UAE). In this study, we determined values of reflectance, emittance, solar reflective index (SRI), and color difference, for three different high-SRI white-paint-coated panels exposed naturally on low- and high-sloped racks for three years. After 3 years, reflectance values of exposed sample panels significantly decreased with an increased color difference in comparison with original unexposed paint surfaces. The emissivity of the paint changed very little for all of the exposed samples, but SRI, determined from both the reflectance and emittance, initially ranged between 95 and 110 and decreased to 60–90 after three years of exposure. This appeared to be related to exposure to high temperatures, UV radiation, and adhesion of airborne contaminants in conjunction with low precipitation. Macroscopically, panels exposed on a low slope were the most discolored with the greatest presence of dust infusion and reduction in increase in surface temperatures, which was demonstrated through thermal imaging. Such natural weathering research study is necessary for the development of standard exposure tests and for the determination of various control elements to increase the durability of cool materials in hot and arid climatic conditions of the UAE.

New insights into the deterioration of TiO2 based oil paints: the effects of illumination conditions and surface interactions

Titanium dioxide (TiO2) has been used in numerous paintings since its creation in the early 1920s. However, due to this relatively recent adoption by the art world, we have limited knowledge about the nature and risk of degradation in museum environments. This study expands on the existing understanding of TiO2 facilitated degradation of linseed oil, by examining the effect of visible light and crystallographic phase (either anatase or rutile) on the reactivity of TiO2. The present approach is based on a combination of experimental chemical characterization with computational calculation through Density Functional Theory (DFT) modeling of the TiO2-oil system. Attenuated Total Reflection Fourier Transform Infrared Spectroscopy (ATR-FT-IR) enabled the identification of characteristic degradation products during UV and visible light aging of both rutile and anatase based paints in comparison to BaSO4 and linseed oil controls. In addition, cratering and cracking of the paint surface in TiO2 based paints, aged under visible and UV–vis illumination, were observed through Scanning Electron Microscopy (SEM). Finally, Density Functional Theory (DFT) modeling of interactions between anatase TiO2 and oleic acid, a fatty acid component of linseed oil, to form a charge transfer complex explains one possible mechanism for the visible light activity observed in artificial aging. Visible light excitation of this complex sensitizes TiO2 by injecting an electron into the conduction band of TiO2 to generate reactive oxygen species and subsequent degradation of the oil binder by various mechanisms (e.g., formation of an oleic acid cation radical and other oxidation products).Graphical

Components of photosynthetic activity of cherry trees in the Right-Bank Forest-Steppe of Ukraine

The article presents the results of research on the photosynthetic activity of cherry trees. The aim of the research was to study the morphological, growth and biochemical characteristics of the leaf cover of cherry trees depending on the time of fruit ripening. Observations, analysis and laboratory studies reveal morphological and biochemical features of annual tree growth, total leaf surface and content of green pigments in the leaves which is one of the main indicators of photosynthetic potential of fruit trees. It was established that Dar Mlieva was characterized by the largest total length of annual increments among early ripening varieties, Melitopolʹsʹka krapchasta variety – among medium ripening varieties, and Drogana zhovta variety among late ripening varieties. Aborehenka variety had the largest average length of shoots, and Mirage variety had the smallest length. The number of shoots on the tree and the activity of annual new ramules make the shoot-forming ability. Cherry varieties are divided into groups according to the obtained data: with a high degree of shoot formation – Dar Mlieva, Zoryana, Mirage, Melitopolʹsʹka krapchasta and Drogana zhovta; middle degree – Mliivsky zhovta, Aboriginal, Meotida, Amazon and low degree – varieties Alyonushka, Biryuza, Donetsky uholʹok. Low leaf area of cherry plantations negatively affected the activity of the processes of photosynthesis and productivity of plantations aged 6–8 years and made 14–35 % of the optimal. The content of chlorophyll in the leaves depended largely on the characteristics of the pomological variety, while for the maturity of the fruit, the dependence was not detected. The middle maturity cherry varieties of Mirage and Meotida differed favorably in the content in the leaf of pigments of photosynthesis of carotenoids, chlorophyll a, b, as well as the sum of a + bchlorophylls . The content of these indicators exceeded the indicators of other studied varieties by 25 % on average. Key words: sweet cherry, photosynthesis, total leaf surface, length of annual increments, chlorophyll content.

Weathering of earth-painted surfaces: Environmental monitoring and artificial aging

Relating damage development to the specific environmental conditions is of paramount importance to design effective conservation strategies for archaeological and historical sites. For this reason, artificial weathering is a highly debated topic in materials science applied to Cultural Heritage. In this work, we report on the weathering of decorated earthen plasters from Templo Pintado in Pachacamac (Region of Lima, Peru) and define a methodology to accelerate aging of painted raw earth surfaces. Weathering was simulated by exposing the surfaces to wet-dry and sandblasting cycles and resulting damage was estimated via the amount of material removed from the original surface. The results are in agreement with weathering dynamics observed in situ, which allows designing suitable methodology for the preparation of samples to be used in testing procedures addressing the preservation of surfaces.

A RESEARCH ON METAPHYSICAL, PHYSICAL AND PICTORIAL LIGHT IN PAINTING

Pilinius’dan Kübizm’e resim sanatında ışık konusu geniş bir tarihsel aralığı kapsamaktadır. Bu
 süreç içinde, ışığın resim sanatında kullanımının üslupsal değişimlerin temel bileşenlerinden biri olduğu
 görülmektedir. Bu geniş çerçevede ışığın, metafiziksel, fiziksel ve resimsel olmak üzere üç temel nitelik olarak
 açığa çıktığı görülmektedir. Işık, bir fenomen olarak, doğa gözleminin ve onun resim yüzeyine aktarımının
 asli bir unsurudur. Bu, ışığı fizik yasasına bağlı bir varlık olarak resmetmek anlamında fiziksel bir kullanımdır.
 Rengin “temsil değeri”ne verilen anlam, ışığın ifadesini de bu değerin sınırları içerisinde bulmaktadır.
 Metafiziksel kullanım ise resim tarihinde ışığın sembolik değerinin öne çıkarıldığı kavramsal bir boyutta ele
 alınmıştır. Bu kullanım rengin hem “temsil değeri”ni hem de “özgül değeri”ni barındırabilmektedir. Resimsel
 ışık kavramı ise, doğal ışık kavramından uzak, resim sanatının kendine has kurallarınca belirlenen bir
 resimsel gerçeklik çerçevesinde anlam bulmaktadır. Ancak, bu üçlü dizinin, ışığın resim sanatındaki varlığını
 nitelendirme ve sınıflandırma amacı ile indirgeyici bir yaklaşım ortaya koyması kaçınılmazdır. Çünkü,
 ışığın resim sanatında kullanımları hiçbir zaman “resimsel ışık” konseptinin dışında değerlendirilmemiştir.
 Metafiziksel ışık da fiziksel ya da doğal ışığın temsilinden tamamen farklı bir tarihsel sürece sahip değildir.
 Bu nedenle ışığın resim sanatındaki tarihinin çizgisel bir tarih olmadığını; kavramların ise resim sanatının
 pratikleri içerisinde birbirlerine açılan patikalarla geçişlilik gösterdiğini söylemek mümkün görünmektedir.