Pigments

Material identification of historical objects has a great importance for better understanding and reproduction process of ancient arts as a basic prior to applying the appropriate conservation method. In this research an inscription related to Ansarin house of Tabriz was studied. It has used in open air space under environmental factors which has caused to structural and visual decays. The aim of the study was identification of pigments and ink of script and ornaments by application chemical spot tests, polarized light microscopy, SEM-EDX and FTIR spectrometry. Results have indicated the use of carbon ink in inscription and ultramarine blue (Lapis lazuli), white lead, red lead (minium), massicot (litharge) with chalk as filler and copper alloys as golden pigment. Corrosion products of copper alloys such as carboxylates, appears as a green layer on golden areas.

PROSPECT, a widely-used leaf directional-hemispherical reflectance and transmittance model, currently treats the behaviour of chlorophylls a, b, carotenoids, and anthocyanins uniformly, leading to errors. A finer discrimination among these pigments in lightabsorbing plant tissues should improve the model. In this paper, a new calibration and validation phase of PROSPECT is performed using two comprehensive databases containing hundreds of leaves collected in temperate latitudes in Angers, France, and in a tropical environment in Hawaii, USA. Leaf biochemical (chlorophylls a, b, carotenoids, water, and dry matter) and optical properties (directional-hemispherical reflectance and transmittance measured from 400 nm to 2500 nm) were measured and used in the model development steps. The first step consists in providing distinct in vivo specific absorption coefficients for the leaf pigments using the Angers database. The model is then inverted to predict the biochemical content of intact ...

Remains of colours and ceramics containing pigments testify to the activity of fresco painters who used usual or more specific containers at different stages of the work. The examination of vessels discovered on Swiss soil provides evidence of this.

Staphylococcus aureus and Pseudomonas aeruginosa are bacteria that cause biofilm-associated infections. The aim of this study was to determine the activity of combined betacyanin fractions from Amaranthus dubius (red spinach) and Hylocereus polyrhizus (red pitahaya) against biofilms formed by co-culture of S. aureus and P. aeruginosa on different polymer surfaces. Various formulations containing different concentrations of the betacyanin fractions were investigated for biofilm-inhibiting activity on polystyrene surfaces using crystal violet assay and scanning electron microscopy. A
combination of each betacyanin fraction (0.625 mg mL−1) reduced biofilm formation of five S. aureus strains and four P. aeruginosa strains from optical density values of 1.24–3.84 and 1.25–3.52 to 0.81–2.63 and 0.80–1.71, respectively. These combined fractions also significantly inhibited dual-species biofilms by 2.30 and reduced 1.0–1.3 log CFU cm−2 bacterial attachment on polymer surfaces such as polyvinyl chloride, polyethylene, polypropylene and silicone rubber. This study
demonstrated an increase in biofilm-inhibiting activity against biofilms formed by two species using combined fractions than that by using single fractions. Betacyanins found in different plants could collectively be used to potentially decrease the risk of biofilm-associated infections caused by these bacteria on hydrophobic polymers.

Colour and the composition of folate, ascorbic acid and anthocyanin of strawberry cv. Camarosa was monitored during refrigerated storage at 4 C each day for 6 days. Folate, anthocyanin and ascorbic acid compositions were determined using High Performance Liquid Chromatography (HPLC) with UV-Vis detector. Five forms of folate: 5 methyl-tetrahydrofolate (THF) [65%], 10 formyl-folic acid (28%), 5 methylene-THF (4%), 5 formyl-THF (2%), and THF (<1%) and two forms of anthocyanins: pelargonidin 3-O-glucoside (97%) and cyanidin 3-O-rutinoside (3%) were identified in the fresh strawberries. The total folate content of the fresh strawberries determined using HPLC method was lower than that using microbiological assay. The ascorbic acid content in fresh strawberry was 57 ± 11 mg/100 g of fruit. The colour of the external skin of strawberries was measured using a Hunter colorimeter and showed fluctuation only for L* values (lightness), but a* (redness) and b* (yellowness) values remained constant during the refrigerated storage. There was no positive correlation between a* values and anthocyanin content. Strawberries should be consumed within a day or two after harvest since the reduction of these three bioactive compounds occurred even after a day of refrigerated storage.

This study explains the history and painting technique of one of Pollock's drip and poured paintings from1947, a turning point in his work. Technical investigation of the painting has presented much information, giving a better insight view of the development of Pollock's work, his choice of metals and the layering of the painting.

Blackcurrant (BC) fruits are a rich source of biologically active anthocyanins but little is known of the anthocyanin content of commonly consumed BC products or how processing affects the absorption. We report that whereas fresh and frozen whole BC were a rich source of anthocyanins, containing 897 and 642mg (100gFW)(-1) of total anthocyanins the levels in all other products were substantially lower (0.05-10.3% of the levels in fresh fruit). Further, when the absorption and excretion of BC was assessed in volunteers consuming a portion (100g) of frozen whole BC (642mg total anthocyanins) and, 300g of a BC drink made by diluting concentrated syrup (33.6mg total anthocyanins), only small quantities of BC anthocyanins were excreted in urine (fruit, 0.053±0.022%; drink, 0.036±0.043%; mean percent urinary yield±SD) and they were not detected in plasma. These data indicate that fresh and frozen BC, but not processed products, are rich sources of anthocyanins but, regardless of the food s...

Treatments to inhibit browning, decay and to extend shelf life of ‘Keitt’, ‘Kent’ and ‘Ataulfo’ mango cultivars as a fresh-cut produce were investigated. Combinations of calcium chloride (CaCl2), antioxidants [ascorbic acid (AA), citric acid (CA)] and two commercial film coatings resulted in a reduction of browning and deterioration of fresh-cut mangoes stored at 5 °C, especially for the Ataulfo cultivar. The use of CaCl2 + AA + CA significantly reduced colour deterioration, loss of firmness and did not affect sensory characteristics of fresh-cut mango, with a larger effect in the Ataulfo cultivar. In general, these treatments prevented loss of sugar and vitamin C of cubes during storage at 5 °C. Shelf life of this cultivar was 21 days, while that of Keitt and Kent was only 9 and 12 days, respectively. There is a correlation between carotene and vitamin C content of Ataulfo mango and its longer shelf life compared with the other cultivars.

In due passi del De Administratione, Suger, abate di Saint-Denis, celebra le vetrate policrome
del coro della sua abbaziale, menzionando la spesa profusa per la materia saphirorum
fornita ai maestri vetrai, con riferimento al blu intenso che fortemente caratterizza
le vetrate. Questo articolo si propone di indagare i possibili significati dell’espressione
materia saphirorum, tradotta in maniera discordante e non soddisfacente nelle moderne
traduzioni esistenti e si propone, inoltre, di ricondurre il suo significato al più ampio
contesto in cui si inserisce l’opera di Suger, tenendo in considerazione il valore spirituale
che l’abate assegnava alle vetrate policrome del coro e alle pietre preziose dell’arredo
liturgico, entrambe variamente interpretate come prefigurazioni materiali della Gerusalemme
celeste. L’analisi sarà condotta nel contesto più ampio degli studi sul colore,
che coinvolge aspetti linguistici, culturali ed antropologici. Saranno inoltre considerate
le questioni relative ai cromonimi in uso nel Medioevo, la nomenclatura delle pietre
preziose e gli studi sui pigmenti per vetrate, ricorrendo all’analisi di diverse fonti scritte
medievali (testi esegetici, trattati tecnici, lapidari, enciclopedie) e ai risultati delle analisi
archeometriche eseguite su vetri da finestra risalenti al XII secolo.

BACKROUND:Spirulina platensis (Toliara, Madagascar) provides a food supplement which can fight against malnutrition and food insufficiency in Madagascar. In this country, the current production from three open basins is not sufficient to cover needs, and presents drawbacks such as low productivity and possible contamination. Thus cultivation of S. platensis in a closed photobioreactor opens the possibility of extending this microalga production. In this study, the influence of colour and intensity of the light on S. platensis growth and protein content was investigated in a bubble column.RESULTS: Growth kinetics were obtained for four colours (green, white, red and blue) and four intensities (400, 800, 1000 and 1200 lux) of light. The influence of light colour on Spirulina growth was discussed. The highest productivity (183.6 mg L−1 d−1) and concentration (2643 mg L−1) were obtained for green light at 1200 lux. The protein content was 58%.CONCLUSION: Using green light allows improvement of S. platensis growth. Performance obtained with the closed system was higher than that reported in the literature. Copyright © 2008 Society of Chemical Industry

Pigments are present in all living matter and provide attractive colors and play basic roles in the development of organisms. Human beings, like most animals, come in contact with their surroundings through color, and things can or cannot be acceptable based on their color characteristics. This review presents the basic information about pigments focusing attention on the natural ones; it emphasizes the principal plant pigments: carotenoids, anthocyanins, and betalains. Special considerations are given to their salient characteristics; to their biosynthesis, taking into account the biochemical and molecular biology information generated in their elucidation; and to the processing and stability properties of these compounds as food colorants.

The 2018 technical examination project The Girl in the Spotlight aimed to characterise the materials and techniques that Johannes Vermeer used to paint Girl with a Pearl Earring (c. 1665, Mauritshuis). Five research questions guided the micro-and macro-scale analyses: What can we find out about layers beneath the surface? What steps did Vermeer take to create the painting? Which materials did Vermeer use and where did they come from? Which techniques did Vermeer use to create subtle optical effects? What did the painting look like originally, and how has it changed? This paper concludes the special issue of Heritage Science by summarising the results and putting them in an art-historical and materials history context. Non-invasive macroscopic imaging methods were used to examine the Girl, in conjunction with the (re)analysis of microscopic samples. Here, Vermeer&#39;s painting techniques are revealed using microphoto-graphs made using a high-resolution 3D digital microscope at 140× ...

Paper deals with the main features of different types of white paint, used in painting. It briefly follows the history of pigments, their chemical and pictorial qualities, and explains the advantages and disadvantages of each of the white paints that have been set in the contemporary pictorial practice. Attention is paid to their onomastics, because the text aims to explain the meaning of the popular names of paints, used routinely by artists.
KEYWORDS: colors, paints, names, pigments, white, painting, Kremserweiss, Zinkweiss, Titanweiss

Objective: The current study focuses on R-Phycoerythrin pigment production from Seaweed using different chemical and physical conditions. Methods: In the present study Seaweed was collected from Rameshwaram and identified by CS-MCRI Institute, Mandapam. The collected seaweed was then washed using distilled water for further processing. Using a sterile knife the seaweed was cut into small pieces. The chopped seaweeds were then weighed and subjected to different optimization procedures for pigment production. These equally weighed seaweeds were treated with three varying Buffers at different pH, the buffer showing better O.D value was subjected to different Cell disruption techniques and finally freeze thawed at different temperature stress. Results: The seaweeds were subjected to different chemical and physical stress conditions for R-phycoerythrin production. On optimizing the different buffer solutions for pigment production Sodium phosphate buffer showed maximum O.D of 0.215 when compared to other buffers whereas on providing different pH conditions the O.D value obtained was high at pH 7.2. Different cell disruption techniques were followed for pigment production using the sodium phosphate buffer at pH 7.2 and freeze thaw method was found suitable for the highest pigment production with O.D value of 0.441. Hence after optimization of different extraction procedures, cell disruption followed by freeze & thaw method (−20°C and 25°C) showed maximum R-phycoerythrin content. Conclusion: From the findings, it was also observed that the primary metabolites produced by these organisms may serve as potential bioactive compounds of interest in the Food industries as natural colourant and in cosmetic industries.

This paper presents highlights from the recent paint study at the George Reid House in Colonial Williamsburg, Virginia. Findings show that despite numerous structural changes, a small group of architectural elements belong to the earliest history of this eighteenth-century dwelling, probably dating to the period when the house was owned by Hugh Orr, a prosperous Williamsburg blacksmith, and his wife, Catherine, from c.1740-88. Finishes from this period include verdigris-greens, Prussian blues and a green paint which contains orpiment, the yellow arsenic sulphide whose synthetic form was also known as King's Yellow. In the parlor, orpiment was also found combined with chrome yellow in an early-19th-century wood graining finish. These finds are significant as there are no published examples of orpiment/King's Yellow-based paints in American vernacular contexts.

The term "ochre" has many meanings: a colored stone, a pigment, sunscreen, a curiosity item, a mustard hue, or even an object used for ritual. Ochre found at archaeological sites is described as a range of earthy, ferruginous rocks with red-yellow-purple streaks. The use of ochre in the past has proven valuable for interpreting not only cognitive capabili ties of its users but also for its potential to shed light on behavioral and social factors. The late Pleistocene, and specifically the Middle Stone Age in southern Africa, is a time of significant behavioral and cognitive advances for Homo sapiens-this coincides with the habitual use of ochre. By looking at the collection and use of ochre in the African Middle Stone Age, placed within a global and temporal context, important behavioral conclusions can be made. Ochre has many potential uses, making interpretations of ochre use in the past complicated. Ethnographic and modern analogies are considered as well as the ex perimental work that has been produced by numerous researchers. All accounts have deepened our understanding of the many ways that ochre may have been used in the dis tant past. It is likely that both its color and mineralogical content dictated its use in the past.