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This study aimed to estimate the number of distinct tooth colors using a large dataset of in-vivo CIELAB measurements. It further assessed the coverage error (CE) and coverage error percentage (CEP) of commonly used shade guides and determined the number of shades needed for an ideal guide, using the Euclidean distance (ΔEab) and thresholds for clinical perceptibility (PT) and acceptability (AT) as evaluation criteria. A total of 8153 untreated maxillary and mandibular anterior teeth were measured in vivo using calibrated dental photography. Cardinality was applied to determine the number of unique natural tooth colors. The CE and CEP were calculated for the Vita Classical and Vita 3D-Master shade guides, while the cardinality method was also used to estimate the number of shades required to adequately cover the estimated gamut of natural tooth colors. The cardinality analysis revealed 1173 unique natural tooth colors. The CE for the Vita Classical shade guide was 4.1 ΔEab, with a CEP of 75 % beyond AT, while the 3D-Master shade guide had a CE of 3.3 ΔEab and a CEP of 70 % beyond AT. Based on cardinality computation, 92 discrete shades are required to adequately cover the estimated gamut of natural tooth colors with a CE of 1.2 ΔEab and CEP of 0.3 % beyond AT. Cardinality computations estimated 1173 unique tooth colors while 92 discrete shades are estimated for full coverage. Such a number is impractical for physical shade guides, but new digital tools and 3D printing may offer future solutions. Both, the Vita Classical and 3D-Master shade guides do not fully represent the range of natural tooth colors. This study highlights the limitations of existing shade guides and underscores the potential for new developments. [ABSTRACT FROM AUTHOR]

This study has developed and optimized a machine learning model to accurately predict the final colors of CAD-CAM ceramics and determine their required minimum thicknesses to cover different clinical backgrounds. A total of 120 ceramic specimens (2 mm, 1 mm and 0.5 mm thickness; n = 10) of four CAD-CAM ceramics - IPS e.max, IPS ZirCAD, Upcera Li CAD and Upcera TT CAD - were studied. The CIELab coordinates (L*, a* and b*) of each specimen were obtained over seven different clinical backgrounds (A1, A2, A3.5, ND2, ND7, cobalt-chromium alloy (CC) and medium precious alloy (MPA)) using a digital spectrophotometer. The color difference (ΔE) and lightness difference (ΔL) results were submitted to 39 different models. The prediction results from the top-performing models were used to develop a fusion model via the Stacking integrated learning method for best-fitting prediction. The SHapley Additive exPlanation (SHAP) was performed to interpret the feature importance. The fusion model, which combined the ExtraTreesRegressor (ET) and XGBRegressor (XGB) models, demonstrated minimal prediction errors (R2 = 0.9) in the external testing sets. Among the investigated variables, thickness and background colors (CC and MPA) majorly influenced the final color of restoration. To achieve perfect aesthetic restoration (ΔE<2.6), at least 1.9 mm IPS ZirCAD or 1.6 mm Upcera TT CAD were required to cover the CC background, while two tested glass-ceramics did not meet the requirements even with thicknesses over 2 mm. The fusion model provided a promising tool for automate decision-making in material selection with minimal thickness over various clinical background. [Display omitted] • Fusion Machine Learning (ML) model accurately predicts the final color of CAD-CAM restoration. • Ceramic thickness is the most influential factor in predicting the desired color outcome. • ML model assists in material selection and determining optimal restoration thickness over various clinical backgrounds. [ABSTRACT FROM AUTHOR]

Although point features have shown their usefulness in classification with Machine Learning, point cloud visualization enhancement methods focus mainly on lighting. The visualization of point features helps to improve the perception of the 3D environment. This paper proposes Multi Feature-Rich Synthetic Colour (MFRSC) as an alternative non-photorealistic colour approach of natural-coloured point clouds. The method is based on the selection of nine features (reflectance, return number, inclination, depth, height, point density, linearity, planarity, and scattering) associated with five human perception descriptors (edges, texture, shape, size, depth, orientation). The features are reduced to fit the RGB display channels. All feature permutations are analysed according to colour distance with the natural-coloured point cloud and Image Quality Assessment. As a result, the selected feature permutations allow a clear visualization of the scene's rendering objects, highlighting edges, planes, and volumetric objects. MFRSC effectively replaces natural colour, even with less distorted visualization according to BRISQUE, NIQUE and PIQE. In addition, the assignment of features in RGB channels enables the use of MFRSC in software that does not support colorization based on point attributes (most commercially available software). MFRSC can be combined with other non-photorealistic techniques such as Eye-Dome Lighting or Ambient Occlusion. [ABSTRACT FROM AUTHOR]

The aim of this research work was to study the color's behavior in pigmented or nonpigmented concretes after ten years exposure to an industrial environment. The fresh and hardened properties correspond to those of self-compacting concretes. On two different surfaces the color was characterized using the CIELAB model, while the color variation differences were determined by means of the CIEDE1976 formula to compare the initial aesthetic values with those measured after ten years exposure. The experimental results showed the effect of each surface exposure condition. The final state was evaluated by comparing the difference in darkness between the most and least exposed surfaces. Finally, the samples retained their original hue and chromaticity. • Color stability was studied in architectural self-compacting concrete for ten years. • The color was characterized using the CIELAB color space. • Color stability was characterized using CIEDE1976 formula. • The direct weathering exposure increased changes in the original color. • The main changes in color are due to dark surfaces. [ABSTRACT FROM AUTHOR]

To verify the color change and contrast ratio of resin composites after curing and after 30 days of storage in water. Dentin A2 shades of different light-cured dental resin composites (Vittra APS, FGM, Brazil; Z350 XT, 3M ESPE, EUA; Tetric N-Ceram, Ivoclar Vivadent, Liechtenstein, and Charisma Diamond, Heraeus Kulzer, Germany) were tested. Ten rounded specimens (8 mm × 2 mm) were prepared for each material. Reflectance for all samples was obtained using a spectrophotometer (Minolta CM 3700d, Konica Minolta, Japan) before curing, immediately after curing, and after 30 days of storage in water. The color change (ΔE* lab) and contrast ratio (CR) data were analyzed using a one-way analysis of variance with Tukey's and paired t-tests (α = 1%). For all materials tested, significant color changes were noticeable after curing and after 30 days in water (p < 0.01). Significant changes in the CR values before curing, after curing, and 30 days of storage in water were observed in the resin composites investigated (p < 0.01) except for Z350 (p > 0.01). The CR values and color changes after curing and 30 days of storage in water varied depending on the material tested. This study corroborates the clinical practice of curing a small amount of unpolymerized resin composite on the tooth surface to select the desired shade before undertaking esthetic restorative procedures. [ABSTRACT FROM AUTHOR]

• Rosé wine color, aromas and phenolics were highly impacted by storage conditions. • Flint bottle under fluorescent light at 22 °C was the most detrimental condition. • Wines stored in darkness at 12 °C showed the smallest changes in composition. • Panelists discriminated the wines based on storage conditions after six months. The majority of rosé wines are bottled in clear bottles as color is an important factor in consumer preference. Post-bottling wine can be exposed to UV–visible light and temperature fluctuations resulting in quality degradation. This study investigated the impact of bottle color (flint and antique green), light exposure (darkness, LED and fluorescent bulb), and temperature (12 °C and 22 °C) on rosé wine quality using a full factorial design with three different wines (Grenache, Pinot noir and Zinfandel). The impact on chemical composition, color, phenolics and aromatics was determined. Projective mapping was carried out for sensorial analysis. Changes in the aromatics, color and phenolic composition were detectable after three months and more noticeable after six months of storage. Overall, all variables studied impacted rosé wine characteristics significantly. However, higher temperature in combination with clear glass bottles under fluorescent light were the most detrimental conditions. [ABSTRACT FROM AUTHOR]

• PVPP treatment of rosé wines had an impact on their color, phenolic composition and thiol content. • Coumaroylated anthocyanins, flavonols and flavanols were highly affected by the PVPP treatment. • An important gain in thiols was observed for the PVPP treated wines compared to the control. • The effect on thiols was PVPP dose dependent. Fining treatment with polyvinylpolypyrrolidone (PVPP) is often used during winemaking of rosé wines. It can modulate the intensity and hue of their pink color and prevent some organoleptic degradations. In this paper, the effect of PVPP treatments on rosé wine during fermentation was investigated by measuring color, polyphenol content and thiol aromas. As expected, colorimetry results showed a decrease in color, indicating some adsorption of anthocyanins and other pigments. This was confirmed by UPLC-ESI-MS/MS analyses. Specific adsorption of certain families of polyphenols was evidenced. Flavonols, flavanols and anthocyanins, especially coumaroylated anthocyanins were preferentially adsorbed by PVPP. The thiol content (3-sulfanylhexyl acetate (3SHA) and 3-sulfanylhexan-1-ol (3SH)) was usually higher after PVPP treatments, in a dose dependent manner. A possible explanation is that the partial adsorption of some polyphenols at an early stage of fermentation would later limit the amount of quinone compounds able to trap thiol aromas. [ABSTRACT FROM AUTHOR]

This work analyzed the use of electrocoagulation as substitute for sugarcane clarification process using sulfitation. It was evaluated technological parameters (Icumsa color and turbidity), phenolic compounds content and CIELAB color parameters. Four kinetics of reduction color from sugarcane juice were carried out. The essays were divided according to the voltage applied: 35, 45, 55 and 65 V (also based on previous tests). Higher voltage treatments achieved greater reduction of Icumsa color, turbidity and total phenolic compounds. However, none of treatments impacted simple phenolic content analyzed in this work. Tristimulus analysis presented some pattern that went beyond technological analysis, including that 65 V essay changed the pigmentation of sugarcane juice and had an early stabilization on chroma. This kind of results could be useful for industry, once they could correlate quality with different color parameters and finally improve the clarification in general with finer settings of technique according to different situations. Unlabelled Image • The electrocoagulation treatment significantly reduced Icumsa color, turbidity and total phenolic compounds. • All treatments did not influence in simple phenolic content analyzed in this work. • Electrocoagulation can change the pigmentation, chroma and lightness of sugarcane juice. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Polyphenolic profile was shown to be an useful tool to identify the wood used in cooperage. • Specific flavonoids were suggested as indication of heartwood botanical origin. • Color of analyzed wood samples was affected by the botanical origin of wood samples. • Shape and maxima positions of fluorescence spectra varied more among wood samples than among corresponding wood extracts. • Principal component analysis of emission spectra discriminated black locust and cherry from the other wood samples. Abstract The aim of this research was to study phenolic compounds of diverse botanical species of wood commonly used in cooperage in Balkan countries. Several botanical species have been considered including mulberry (Morus alba L.), myrobalan plum (Prunus cerasifera Ehrh.), black locust (Robinia pseudoacacia L.), wild cherry (Prunus avium (L.) L.), and oak (Q. petraea (Matt.) Liebl. , Q. robur L., and Q. cerris L.). A total of 37 compounds were quantified, demonstrating the presence of phenolic acids, flavonols, flavones, flavanones, flavanonol taxifolin, stilbenoids, and coumarins. Taxifolin was the most abundant in wild cherry (8455.70 mg kg−1), while ellagic acid predominated in oak wood (8872.05–10099.32 mg kg−1 in sessile oaks, and up to 15,958.80 mg kg−1 in pedunculate oak from Slavonia). The highest content of protocatechuic acid (533.39 mg kg−1) was found in myrobalan plum. Also, isoflavones were characteristic of wild cherry, while mulberry was abundant in stilbenoids. Total phenolic content, as well as antioxidant, chromatic, and fluorescence properties were studied. The spectral shapes and maxima of fluorescence emission spectra of bare wood samples were compared with those of the corresponding wood extracts. The Principal Component Analysis (PCA) was applied in order to find patterns in emission spectra for differentiation among wood samples. [ABSTRACT FROM AUTHOR]

The aim of this research is to investigate optical and photocatalytic properties of 0.25, 0.5 and 1.0 mol% BiVO 4 doped bismuth silicate glasses. The glasses composition is 60 mol% SiO 2 and 40 mol% Bi 2 O 3. Optical spectra and the analysis of color by CIELab system revealed that the addition of BiVO 4 changed the color of the glasses from pale yellow to yellow-orange with the narrower band gap. Photocatalytic activity was observed in 0.5 and 1.0 mol% BiVO 4 -doped glass. The effect of BiVO 4 doping to bismuth silicate glass is also discussed. [ABSTRACT FROM AUTHOR]

Abstract The bismuth silicate glasses with the composition of 60% by mole of silica and 40% by mole of bismuth oxide were prepared with neodymium and erbium added at 0.1, 0.3, 0.5 and 1 at%. The glasses were melted and the measurement in terms of transmittance was used to analyze absorbance and energy band gap from optical spectra. Neodymium changed the bismuth silicate glass to dark violet color and erbium decolorized the glass with a small addition and turned to light pink when the concentration increased. Transmittance and absorption of glasses changed with the amount of dopant. The major absorption peaks of neodymium added were at 520 and 560 nm and erbium characteristic absorption peaks at 480, 525 and 650 nm. [ABSTRACT FROM AUTHOR]

In this study, microwave heating was employed for controlling Oryzaephilus surinamensis adult beetles infesting stored Iranian dried figs. The dried fig samples were artificially infested with O. surinamensis and then heated in a microwave oven (2,450 MHz) at power outputs of 450, 720, and 900 W for 20, 30, 40, and 50 s. Changes in the color of the samples after these microwave applications were evaluated for lightness (ΔL*), redness (Δa*), and yellowness (Δb*) using an image processing technique. Both parameters of microwave power and exposure time had significant effects on beetle mortality (P < 0.01). A direct positive relationship was found between the mortality rate and microwave power. Complete mortality was achieved at 900 Wand for 50 s. The color parameters of the dried fig samples did not change significantly. These results indicate that microwave irradiation can be introduced as an appropriate alternative to chemical fumigants without affecting product quality. [ABSTRACT FROM AUTHOR]

Fruits of Lycium barbarum L. have been used in Chinese traditional medicine for centuries. In the last decade, there has been much interest in the potential health benefits of many biologically constituents of these fruits. The high level of carotenoids offers protection against development of cardiovascular diseases, diabetes and related comorbidities. In the present work two different selections of Lycium barbarum L., cultivated in Italy and coming from three discrete harvest stages, were subjected to two different grinding procedure and to a simplified extraction method of carotenoid component. CIELAB colorimetric analysis of the freshly prepared purees and HPLC-DAD analysis of carotenoid extracts were performed and compared. Different harvesting dates and grinding procedures deeply influence the carotenoids content and statistical analysis showed high correlation between carotenoid content and colorimetric data. The final model provides a reliable tool to directly assess carotenoid content by performing cheap and routinely colorimetric analyses for food industry. [ABSTRACT FROM AUTHOR]

This research focuses on optical properties of bismuth silicate based glasses. The glasses with the composition 60SiO 2 -40Bi 2 O 3 were prepared and 3d transition metals (Cr, Mn, Fe, Co, Ni and Cu) with 0.1, 0.3, 0.5 and 1 at% were added. Optical spectra in terms of transmittance were used to analyze color shade with CIELab analysis in all glasses. Transmittance of glasses was changed in intensity and dominant wavelength when the transition metals were incorporated. This resulted in the change of lightness and color shade or CIELab values. Localization of 3d transition metals resulted in change of optical properties by non-bridging oxygen ions, which acted as network modifier. [ABSTRACT FROM AUTHOR]

The main goal of the paper is the optical and colorimetric characterization of the pigment mixtures realized with pure pigments of the principal artist's hues and white pigments through spectrophotometric analysis. This research work represents a first step in a methodology study aimed to the verify potentialities and limits of spectrophotometric techniques in the identification of pigments in mixtures. The analysis regarded the trend of Spectral Reflectance Factor (SRF%) in visible spectrum and of the derivative of SRF, d(SRF%). In particular, the analysis of d(SRF%) of the mixture in the function of achromatic pigment concentration has the aim of highlight shift of the extrema points in relation to the relative quantities of the mixture components. To this aim, painting samples were prepared in laboratory mixing the coloured pigments with achromatic ones in variable weight concentration from 10% to 90% for each of the components. This is necessary to evaluate the minimum quantities of white that could change the coloured pigments SRF% spectra. Also the analysis of colour coordinates is performed to put in evidence the L*, a*, b* trend in CIELAB 1976 space. [ABSTRACT FROM AUTHOR]

In human visual processing, information from the visual field passes through numerous transformations before perceptual attributes such as colour are derived. The sequence of transforms involved in constructing perceptions of colour can be approximated by colour appearance models such as the CIE (2002) colour appearance model, abbreviated as CIECAM02. In this study, we test the plausibility of CIECAM02 as a model of colour processing by looking for evidence of its cortical entrainment. The CIECAM02 model predicts that colour is split in to two opposing chromatic components, red-green and cyan-yellow (termed CIECAM02-a and CIECAM02-b respectively), and an achromatic component (termed CIECAM02-A). Entrainment of cortical activity to the outputs of these components was estimated using measurements of electro- and magnetoencephalographic (EMEG) activity, recorded while healthy subjects watched videos of dots changing colour. We find entrainment to chromatic component CIECAM02-a at approximately 35 ms latency bilaterally in occipital lobe regions, and entrainment to achromatic component CIECAM02-A at approximately 75 ms latency, also bilaterally in occipital regions. For comparison, transforms from a less physiologically plausible model (CIELAB) were also tested, with no significant entrainment found. [ABSTRACT FROM AUTHOR]

The impact of co-fermenting white grape pomace (WP) and red grape pomace (RP) on the composition of interspecific hybrid wine was studied using the Vitis sp. ‘Frontenac’ and ‘Vidal’. The proanthocyanidin and anthocyanin content of the resulting wines were analysed by HPLC-fluorescence and UPLC–MS/MS, respectively. The CIELAB parameters and volatile compounds were analysed using spectrophotometry-UV and GC–MS-SPME, respectively. The WP addition increased the concentration of monomeric and oligomeric flavan-3-ols, and terpenes in the wines. The manipulation of the WP/RP ratio efficiently modulated the anthocyanin profile of the wines, resulting in faded red colour, a desirable achievement in hybrid red wine, which is usually perceived as too dark. An appropriate ratio (30% RP/6% WP) improved the colour stability of the wines without a significant impact on wine colour. Addition of WP proved to be a suitable tool to modulate the colour, the phenolic and volatile composition of interspecific hybrid wine. [ABSTRACT FROM AUTHOR]

Changes in phenolic profiles and color parameters can help to differentiate between extra virgin olive oils (EVOOs) with protected designation of origin (PDO). Phenolic profile characterization and CIELAB parameters determination of 9 PDO EVOOs from Spain were developed. Both properties of EVOOs are very relevant to their commercialization and increase the product value. The Serrana de Espadán olive cultivar was characterized for the first time and showed the highest pinoresinol concentrations and clarities in these olive oils, which are important values for the product image. To detect fraudulent instrumental work and implement quality control, principal component analysis (PCA) and linear discriminant analysis (LDA) were performed. EVOO geographical origin and cultivar distributions were achieved with cumulative variances of 93.4% and 92.4%, respectively. A categorization of PDO EVOOs was proposed using the following 7 phenolic compounds: phenolic alcohols (tyrosol and hydroxytyrosol), 3,4-DHPEA-EDA, 3,4-DHPEA-EA, p -HPEA-EDA, pinoresinol and total phenolic compounds. [ABSTRACT FROM AUTHOR]

The purpose of this study was to assess the relationship between the effect of regulated deficit irrigation, cluster, developmental stages and two seasons (autumn 2015 and spring 2016) on the commercial and functional quality (carotenoids and plenolics levels) in ‘Lazarino’ and ‘Summerbrix’ tomatoes. Autumn had a positive effect on the commercial quality, with larger fruits (22% in ‘Summerbrix’; 26% in ‘Lazarino’) and higher soluble solids (16% in ‘Summerbrix’; 12% in ‘Lazarino’). Total carotenoids did not change significantly with irrigation and variety while total phenolics did with the cluster and season. In most cases, the main amounts of carotenoids and phenolic were found in the higher cluster and carotenoids in ripe fruit. Thus, irrigation of such varieties could be reduced drastically (ca. 80%) without affecting considerably the overall quality of their fruits (changes not greater than 30%). [ABSTRACT FROM AUTHOR]

Colour is the first organoleptic property that consumers appreciate of a foodstuff. In blueberry ( Vaccinium spp . ) fruits, the anthocyanins are the principal pigments determining the colour as well as many of the beneficial effects attributed to this functional food. Commercial blueberry-derived products represent important sources of these healthy molecules all year round. In this study, blueberries were produced into purees comparing two homogenization methods and further heated following different thermal treatments. All the supernatants of the homogenates were monitored for pH. Then, the hydroalcoholic extracts of the same samples were characterized by CIELAB and HPLC-DAD analyses. These analytical techniques provide complementary information on fruit pigments content as a whole and on quali-quantitative profile of the single bioactive colorants. These data could be very interesting to know the best manufacturing procedure to prepare blueberry-derived products, well accepted by the consumers, while maintaining their healthy properties unaltered. [ABSTRACT FROM AUTHOR]

Understanding grape berry development and the metabolism of different classes of compounds responsible for traits like berry's color is imperative to control and improve quality aspects of grapes. A colorimetric, biochemical and molecular characterization allowed the comprehensive description of the pigment-related characteristics of nine berry skin color somatic variants, belonging to four different varieties. Although the observed berry skin color variability was not fully explained by MybA locus, the phenolic profiles allowed inferring about specific interferences among the biosynthetic pathways. Data were consistent concerning that grapes showing cyanidin-3- O -glucoside as the major anthocyanin and flavonols with two substituent groups in the lateral B-ring are generally originated by a white ancestor. After retro-mutation, these grapes seem to keep the dysfunction on flavonoid hydroxylases enzymes, which negatively affect the synthesis of both flavonols and anthocyanins with three substituent groups in the lateral B-ring. Overall, the obtained results indicate that the color differences observed between somatic variants are not solely the result of the total amount of compounds synthesized, but rather reflect a different dynamics of the phenolic pathway among the different color variants of the same variety. Chemical compounds Gallic acid (PubChem CID: 370); Caftaric acid (PubChem CID: 6,440,397); Catechin (PubChem CID: 73,160); Epigallocatechin gallate (PubChem CID: 65,064); Quercetin-3- O -galactoside (PubChem CID: 5,281,643); Quercetin-3- O -glucoside (PubChem CID: 25,203,368); Malvidin-3- O -glucoside (PubChem CID: 443,652); Peonidin-3- O - p -coumaroylglucoside (PubChem CID: 44,256,849); Malvidin-3- O - p -coumaroylglucoside (PubChem CID: 44,256,988); Resveratrol-3- O -glucoside (PubChem CID: 25,579,167). [ABSTRACT FROM AUTHOR]

[Display omitted] • The lightness of dark coal-fired bottom ash was significantly brightened after Ca(OH) 2 -Na 2 CO 3 activation. • The brightening effect depended on the particle size of raw bottom ash and the substituted ratio of GGBFS and fly ash. • The increase of white reaction products such as C-S-H and CaCO 3 increased the brightening effect. This study demonstrated that the Ca(OH) 2 -Na 2 CO 3 activation produced a near-white surface of hardened samples having a high lightness index using dark coal-fired bottom ash. In this study, the lightness index (L*) (index of black (0) to white (1 0 0)) of raw dark bottom ash was 36.73, but after the activation, the hardened sample showed a significantly increased L* (77.93) (i.e., 112.2% L* increase) with a near-white surface. The Ca(OH) 2 -Na 2 CO 3 -activation also decreased the values of a* (index of green to red) and b*(index of blue to yellow), implying the removal of chromatic colors. However, this whitening effect significantly depended on the particle size of raw bottom ash, controlled by the milling process, and the produced amounts of white reaction products (particularly, C-S-H (gel) and CaCO 3), affected by the milling process and substituted ratios with fly ash and ground granulated blast furnace slag (GGBFS). The compressive strength of the 100 wt% bottom ash sample was only 5.3 MPa at three days, but it was enhanced to have enough strength over 7.4–10.3 MPa (adequate for structural bricks) without losing the surface brightness noticeably (L* > 70) by the milling process or by substituting bottom ash with fly ash or GGBFS. [ABSTRACT FROM AUTHOR]

Rock slope instability causes rock slope failure with intense weathering processes in tropical regions. In addition to the various advanced numerical rock slope stability assessment techniques that have been developed thus far, simple evaluation techniques characterizing the rock slope weathering degree based on color changes of the rock surface remain one of the main techniques used by most geologists onto the rock slope stability assessment. The present study proposed a new evaluation method for weathering assessment of the limestone rock slope with computer-assisted image processing technologies to reduce human-induced errors based on a manual characterization process. The color changes of the limestone rock referring the CIELAB color space, which indirectly indicated the differential weathering of the rock mass, were measured in-situ using the FRU colorimeter with a 40 mm aperture. The Schmidt hammer was used to determine the intact rock strength and validate the color changes of the limestone rock to the International Society For Rock Mechanics (ISRM) weathering grade standard. Results indicated that a* and b* correlated strongly with R2 = 0.7404, underscoring the consistency of the CIEL*a*b color space data obtained in situ. The a* and b* correlated strongly with the uniaxial compressive strength result obtained via the rock Schmidt hammer test, with R2 of 0.7058 and 0.7011, respectively. The results were verified with the weathering grades analyzed using image analysis technique. In conclusion, the CIELAB color space is an effective tool in the preliminary assessment of rock mass weathering, particularly for slightly vegetated rock slope outcrops. • Unmanned Aerial Vehicle photogrammetry has been used to acquire the images. • The a* and b* values are high when the object is extensively weathered. • The R2 is 0.7404 for the correlation of b* vs a* scattering graph of the La*b* data. • The JudGeo result shows that Grade I & II weathered rocks dominate the slope profile. • The Schmidt data shows that Grade III & IV weathered rocks dominate the slope profile. [ABSTRACT FROM AUTHOR]

Quantifying soil organic carbon (SOC) is important for soil management, precision agriculture, soil mapping and carbon dynamics research. Inexpensive sensor technologies offer the potential for rapid quantification of SOC in laboratory samples as well as in the field. The objective of this study was to use a commercially-available color sensor to develop SOC prediction models for both dry and moist soils from the Piedmont region of South Carolina. Thirty-one soil samples were analyzed for lightness to darkness, redness to greenness, and yellowness to blueness (CIEL*a*b*) color using a Nix Pro™ color sensor. Soil color was measured under both dry and moist soil conditions and the depth of each soil sample was also recorded. Using L*, a*, b* and soil depth for each sample as initial predictors, regression analyses were conducted to develop SOC prediction models for dry and moist soils. The resulting residual plots, root mean squared errors (RMSE), and coefficients of determination (R 2 ) were used to assess model fits for predicting the SOC content of soil. Cross validation was conducted to determine the efficiency of the predictive models and the mean squared prediction error (MSPE) was calculated. The final models included soil depth, L*, and a* as independent variables (dry soils R 2 = 0.7978 and MSPE = 0.0819, moist soils R 2 = 0.7254 and MSPE = 0.1536). The results suggest that soil color sensors have potential for rapid SOC determination, and soil depth and color are useful in predicting SOC content in soils. [ABSTRACT FROM AUTHOR]

This study aimed on modern analytical techniques for the isolation, separation and structural identification of the essential bioactive carotenoid Lutein, from green microalga, Chlorella salina . Identification was done by comparing their absorption and mass spectral data with those of reference standard values reported. The extract is separated by selective C 18 columns and the data were then combined with spectroscopic information. Structural assignment of the separated compound is done by HR-MS. The results of the spectral investigation showed that the isolated pigment showed absorbance peak at 445 nm. Total luminescence spectra were recorded by measuring the emission spectra in the range 350–720 nm at an excitation wavelength of 455 nm. The excitation-emission matrices were recorded and two basic fluorescence regions have been obtained. The compound was resolved within 4.36 min by using a C 18 column with a flow rate at 1 ml/min and detection at 450 nm. The compound was detected by a High Resolution Orbitrap-MS with regard to specificity and sensitivity (with limits of detection ranging from 1.0 to 3.8 pg μL −1 ). [ABSTRACT FROM AUTHOR]

Objectives To analyze the influence of lightness, chroma and hue differences on visual shade matching performed by dental students. Methods 100 dental students (DS) volunteers with normal vision participated in the study. A spectroradiometer (SP) was used to measure the spectral reflectance of 4 extracted human upper central incisors (UCI 1-4) and shade tabs from Vita Classical (VC) and Vita Toothguide 3D-Master (3D) shade guides. Measurements were performed over a gray background, inside a viewing booth and under D65 illuminant (diffuse/0° geometry). Color parameters ( L *, a *, b *, C * and h °) were calculated. DS used VC and 3D to visually select the best shade match for each UCI. CIE metric differences ( Δ a * , Δ b * , Δ L ′ , Δ C ′ and Δ H ′ ) and CIEDE2000(2:1:1) lightness ( Δ E L ), chroma ( Δ E C ) and hue ( Δ E H ) differences were obtained from each UCI and the first three shades selected by DS and the first option using CIELAB, CIEDE2000(1:1:1) and CIEDE2000(2:1:1) color difference metrics. The closest CIELAB color-discrimination ellipsoid (from RIT-DuPont visual color-difference data) to each UCI was selected for the analysis of visual shade matching. Results DS showed a preference for shades with lower chroma ( Δ C ′ and Δ E C ) and/or hue ( Δ H ′ and Δ E H ) values instead of shades with lower lightness values ( Δ L ′ and Δ E L ). Most best visual matches were near the tolerance ellipsoid centered on tooth shade. Significance This study is an attempt to partially explain the inconsistencies between visual and instrumental shade matching and the limitations of shade guides. Visual shade matching was driven by color differences with lower chroma and hue values. [ABSTRACT FROM AUTHOR]

The effect of adding an enzymatic hydrolysate of grape seeds (EH-GS) during Syrah wine fermentation in a warm climate has been evaluated. We focused on the polyphenolic composition as well as the application of differential and tristimulus colorimetry to colour data. This is the first attempt at using this oenological alternative to avoid common colour losses of red wines elaborated in a warm climate. The addition of 250 g (simple dose, SW) of EH-GS to 120 kg of fermentation material promoted a significant ( p < 0.05) increase in the polyphenolic content of stored wines, especially in benzoic acid, hydroxycinnamic acid derivative, flavonol and anthocyanin levels. This increase could promote a higher copigmentation percentage and maximum colour stabilization ( C ∗ ab ) without significantly changing the wine tonality. Unexpectedly, the use of a double quantity (DW) of EH-GS resulted in significantly less chroma than for control wines (CW), demonstrating visually perceptible colour changes (Δ E ∗ ab > 3 CIELAB units). [ABSTRACT FROM AUTHOR]

The feasibility of a colorimetric technique was investigated in CIELAB color space as an analytical quality control method for content uniformity of printed orodispersible pediatric delivery systems. Inkjet printing was utilized to fabricate orodispersibe film formulations containing propranolol hydrochloride in a colored ink base using three different edible substrates. A thin sweetener coating layer of saccharin was successfully included in the final dosage forms for palatability purposes using a casting knife. Optical microscopy, scanning electron microscopy and scanning white light interferometry analyses were conducted to study the effect of printing on the surface morphology and topography of the substrates. Differential scanning calorimetry and attenuated total reflectance infrared spectroscopy were used to study the solid state properties and possible interactions between the drug and the excipients. The inkjet printing technique deposited precise and uniform escalating doses (0.08–3.16 mg) of the active pharmaceutical ingredient onto the substrates (R 2 ≥ 0.9934). A disintegration test with clear end-point detection confirmed that all the substrates meet the requirements of the Ph. Eur. to disintegrate within 180 s. The colorimetric technique proved to be a reliable method to distinguish the small color differences between formulations containing an escalating dose of propranolol hydrochloride. [ABSTRACT FROM AUTHOR]

We introduce a novel method to detect and classify the severity of bacterial spot ( Xanthomonas spp.) in tomato ( Solanum lycopersicon ) fields. Visual spectrum images were used as inputs and they were taken at 85 days of the plantation. Two hybrids, Hypeel 108 and U2006, were planted and then inoculated separately with X. perforans and X. gardneri , respectively at 37 and 57 days. Ten (10) different plantation areas were then evaluated taking 18 image samples of each in sub-areas, which were analyzed by 7 experts to grade them and be used as comparison. Productivity was also measured in the areas in order to correlate those to the different severities of the disease in the experiment. Visual spectrum images were preprocessed to area size adjustment and brightness correction and then transformed to a CIELab color space for more stable chroma analysis. A clustering process was applied in the a channel in order to group regions related to healthy leaves, unhealthy ones, bare soil and other artifacts. Post-filtering was applied to channels L and b to evaluate regions with over and underexposition of light and reddish fruits being detected. All of the processed regions were then measured and compared using a novel Severity Index SI , which automatically grades, from 1.0 to 5.0, the presence and the severity of the disease. Sixteen classes of severity SC are also proposed, as equal intervals of SI index. Images were taken in a variety of conditions and results showed besides strong correlation with experts analysis, better explanation and smaller error when analyzing the productivity affected by the disease measurements. Results indicate potential for using this methodology for detecting and grading the severity of bacterial spot in tomato fields, with advantages such as capability of repeatable results with low variance, speed and direct field-based applicability. [ABSTRACT FROM AUTHOR]

Glutathione (GSH) and ascorbic acid (AA) are often added as antioxidants in wines for a better preservation of aroma. However, depending on the dosage of these substances, changes in colour may occur in the wines. The paper presents the effect of the addition of glutathione, with or without ascorbic acid, on the colour of Muscat Ottonel wines after 4 months of ageing in bottles. The dosage of ascorbic acid varied between 30 and 70 mg/l and that of glutathione between 10 and 100 mg/l, while in the samples where both glutathione and ascorbic acid were added the latter was kept constant at 30 mg/l. All wines contained the same amount of sulphur dioxide at the moment of addition, namely 80 mg/l total and 42 mg/l free, respectively. The analysis took into account 3 groups of samples: only with glutathione, only with ascorbic acid and with combination of glutathione and ascorbic acid. The CIE Lab colour parameters were determined and the colour components compared for the three groups and the control. The results showed that during storage the colour of wines evolved, parameter a showing in most samples a shift toward more red component. The most significant colour change was recorded for the samples treated only with glutathione, while the presence of ascorbic acid, with or without glutathione, lowered the value of parameter a . A synergistic effect in lowering the values of both parameter a and b was observed in the samples treated with combinations of ascorbic acid and glutathione at higher concentrations. The results suggest that a combination of glutathione and ascorbic acid may confer better stability of colour of white wines during storage. [ABSTRACT FROM AUTHOR]

Synthetic inorganic pigments based on citrus pectin and metal (aluminum, iron, cobalt, and nickel) nitrates were prepared by a novel, fast, economical synthesis method that did not generate wastes. It involved gelling at 80 °C (4 h) and calcination at 600 °C (3 h). Samples' thermal (TG/DTA) and morphological (SEM) behaviors, size distribution (DLS), surface areas and porosities (BET), molecular spectroscopic (Raman spectroscopy) and electronic (UV–Vis spectroscopy) behaviors, and colors (CIELab) were investigated. Characteristic data indicated pigments had morphologies typical of porous materials with 1.40–1.64 μm particle size, which is ideal for pigment applications. Thermal curves showed an organic fraction after calcination at 600 °C, which gave a softness to the pigments. Cytotoxicity tests revealed that toxicity was within tolerable limits, and dispersion tests in commercial colorless paint showed increasing coating capacity with decreasing paint volume while maintaining color, as verified by colorimetric measurements. [ABSTRACT FROM AUTHOR]

The purpose of this trial was to develop an objective internal flesh browning (IFB) assessment methodology for fresh peach. Six peach and three nectarine cultivars were used in this research. The fruit was maintained at 4 °C for 21 and 31 days. They were then evaluated after three additional days of maintenance at 20 °C. The differences in the CIELAB color parameters of the flesh Δ L *, Δ E *, Δ h °*, Δ C *, Δ a *, and Δ b * were then assessed. Δ L * were assessed with both fresh fruit and fruit after postharvest treatments; after regression analysis, this resulted in the best CIELAB parameter to describe IFB. A trained sensory panel was used to corroborate the results. Between Δ L * and the panel assessment of IFB, was obtained the highest determination coefficient ( R 2 = 0.84). Furthermore, through a triangular test, it was determined that Δ L * = 4.7 corresponds to the IFB peach flesh threshold, as perceived by the panel. Afterward, through a regression tree, four IFB categories were defined: (1) no IFB symptoms, when Δ L * < 4.7; (2) incipient IFB symptoms, when 4.7 ≤ Δ L * < 8.0; (3) severe IFB symptoms, when 8.0 ≤ Δ L * < 21; and (4) extreme IFB symptoms, when Δ L * ≥ 21. We recommend the use of Δ L * when objective phenotyping of IFB of peach flesh is required. [ABSTRACT FROM AUTHOR]

A method has been developed to automatically characterize the type of mineral phases by means of digital image analysis using optical properties of crystals. The method relies on microscope automation, digital image acquisition, image processing and analysis. Two hundred series of digital images were taken from 45 standard thin sections using a digital camera mounted on a conventional microscope and then transmitted to a computer. CIELab color space is selected for the processing, in order to effectively employ its well-defined color difference metric for introducing appropriate color-based feature. Seven basic optical properties of minerals (A. color; B. pleochroism; C. interference color; D. birefringence; E. opacity; F. isotropy; G. extinction angle) are redefined. The Local Binary Pattern (LBP) operator and modeling texture is integrated in the Mineral Identification (MI) scheme to identify homogeneous regions in microscopic images of minerals. The accuracy of mineral identification using the method was %99, %98, %96 and %95 for biotite, hornblende, quartz and calcite minerals, respectively. The method is applicable to other minerals and phases for which individual optical properties of crystals do not provide enough discrimination between the relevant phases. On the basis of this research, it can be concluded that if the CIELab color space and the local binary pattern (LBP) are applied, it is possible to recognize the mineral samples with the accuracy of more than 98%. [ABSTRACT FROM AUTHOR]

Lemons and grapefruit are harvested commercially before the fruit have reached their characteristic colour and are submitted to a process of degreening in special chambers before entering the retail chain. The aim of this work is to make a cost analysis of this process for different times of harvest. The period analysed ran from October to December in 2012 and 2013. Fruit were harvested on six occasions in each year (T1–T6) and the fruit classified into seven lots each time (three for lemon and four for the grapefruit cultivars studied). The lemon cultivars studied were ‘Eureka’, ‘Fino 49’ and ‘Lisbon’ on Citrus macrophylla and the grapefruit cultivars were ‘Marsh’, ‘Red Blush’, ‘Río Red’ and ‘Star Ruby’ on the mandarin Cleopatra. Each lot remained in the ethylene chamber for 7 days, and the colour coordinates were measured every 2 days to obtain the Colour Index (CI*) of the fruit for each harvesting date. The data showed that the greener the fruit when they entered the ethylene chamber, the greater the degreening rate. The different costs of degreening were estimated for each harvesting date and cultivar. The findings showed that the costs involved in degreening the grapefruit cultivars ‘Red Blush’ and ‘Rio Red’ were three times greater than the costs associated with ‘Marsh’ and ‘Star Ruby’. The costs of degreening lemon did not differ during the first half of the harvesting period and fell gradually during the second half. The findings provide a useful tool for calculating the cost of degreening as a function of harvesting date for each cultivar. [ABSTRACT FROM AUTHOR]

Highlights: [•] Colour and antioxidant capacity changes over the oxidation of β-carotene studied. [•] Nineteen different carotenoids were detected during the oxidation reactions. [•] Some colour parameters seemed useful to detect the formation of oxidation products. [•] Some mixtures of oxidation products showed greater antioxidant capacity than β-carotene. [ABSTRACT FROM AUTHOR]

Highlights: [•] The same berry quality parameters were obtained with full and deficit irrigation. [•] Seedless table grape cultivars were successfully grown in Northeast Spain. [•] Splitting daily irrigation reduced berry cracking in the Autumn cultivar. [•] Shoot pruning and deficit irrigation enhanced skin color in the Crimson cultivar. [ABSTRACT FROM AUTHOR]

Highlights: [•] The method for evaluating heterogeneous colours in foodstuffs has been improved. [•] An algorithm that adjusts point clouds to ellipsoids in CIELAB colour space has been introduced. [•] The methodology presented can be useful in studies that use ‘Chemical Imaging’. [Copyright &y& Elsevier]

Abstract: Organic compounds present in plants have been used in various experimental conditions for dyeing tests aimed to develop safe and environmentally friendly temporary and semipermanent hair dyes. Yak hairs were used as a model for the colorimetric evaluation of red, yellow, blue, and brown shades conferred to hair by selected natural compounds. Two different sources for red, yellow, blue and brown shades were tested. Anthocyanins from mulberry fruits and alizarin emerged as promising candidates for red shades, anthocyanin-blue and curcumin for blue and yellow, respectively, and p-benzoquinone and juglone for browns. The influence of pH, dye concentration, soaking time, and medium in which the dyes have been dissolved or dispersed has been studied. [Copyright &y& Elsevier]

Abstract: A study of the changes of copigmentation phenomenon in wines elaborated from different varieties has been undertaken. Colorimetric measurement of Tempranillo (T) and Graciano (G) monovarietal wines, and two 80:20 blend wines: M, (grape blending T and G, co-maceration) and W (wine blending T and G, co-vinification) was performed by spectrophotometry. Significant differences (p<0.05) were found among the color of the wines. The Graciano cv. afforded somewhat darker and more colorful wines than the other wines. The color difference values, ΔE*ab suggested that co-vinification (W) led to wines being more similar to T than the co-maceration (M). The ΔE*ab[w−c] between untreated wines – whole wines, w – and the wines diluted to eliminate copigmentation – corrected wines, c – was 14.2 CIELAB units in the initial stages of winemaking and 6.7 in the final stages. M had a greater proportion of color due to copigmentation than the monovarietal wines. Evaluation of this parameter confirms the importance of copigmentation process into wine color during the early stages of the vinification. Also, through the full spectrum, quantitative data obtained allow a visual interpretation of the changes involved. In addition, with the aging in bottle, M wines had more stable color and more different color than W wines. [Copyright &y& Elsevier]

Abstract: Color perception plays a major role in the consumer evaluation of perfume quality. Consumers need first to be entirely satisfied with the sensory properties of products, before other quality dimensions become relevant. The evaluation of complex mixtures color presents a challenge even for modern analytical techniques. A variety of instruments are available for color measurement. They can be classified as tristimulus colorimeters and spectrophotometers. Obsolescence of the electronics of old tristimulus colorimeter arises from the difficulty in finding repair parts and leads to its replacement by more modern instruments. High quality levels in color measurement, i.e., accuracy and reliability in color control are the major advantages of the new generation of color instrumentation, the integrating sphere spectrophotometer. Two models of spectrophotometer were tested in transmittance mode, employing the d/0° geometry. The CIEL ⁎ a ⁎ b ⁎ color space parameters were measured with each instrument for 380 samples of raw materials and bases used in the perfume compositions. The results were graphically compared between the colorimeter device and the spectrophotometer devices. All color space parameters obtained with the colorimeter were used as dependent variables to generate regression equations with values obtained from the spectrophotometers. The data was statistically analyzed to create predictive model between the reference and the target instruments through two methods. The first method uses linear regression analysis and the second method consists of partial least square regression (PLS) on each component. [Copyright &y& Elsevier]

Abstract: Optical spectroscopy allows the identification of ionic species and, under certain conditions, the quantification of Fe + and Fe3+. The ratio of the oxidation states of iron gives an insight into the technological aspects of production. Moreover from the transmission spectra it is possible to calculate the CIE Lab colour coordinates and the UV absorption edge. The latter parameter is strongly related to the presence of heavy elements because they disrupt the silica polymer network. The optical parameter highlights differences in the sample population allowing the definition of subgroups. A comparison between colour coordinates, iron redox ratios, UV absorption edge and the chemical composition is presented. The results provide important information about the proportion between different compositional groups available from the archaeological site and underline the potentiality of UV-Vis-NIR absorption spectroscopy as a first-step screening method for large sets of archaeological or historical glass fragments. The present case-study demonstrates the results of optical spectroscopy on a selection of 16 late Roman “naturally” coloured glass fragments from the Roman villa complex ‘les Bruyeres’ in Treignes (Belgium). [Copyright &y& Elsevier]

Abstract: The double-pass solar drier (DPSD) and standard laboratory oven (LO) were used for drying of jerky from eland (Taurotragus oryx) meat. Instead of traditional jerky marinade a marinade with honey syrup (50% bee honey/50% distilled water) were used as drying pretreatments in this study. Higher drying rate was observed in DPSD where the reduction of moisture content from initial 72% (w.b.) to desired 30% (w.b.) was achieved after 8hours instead of LO drying where it took 10hours. The results also show that best color preservative effect was achieved when the traditional jerky marinade is combined with honey syrup. Finally we can conclude that DPSD is suitable facility for jerky drying and eland meat is one of new potential sources for this kind of popular, shelf-stable and nutrient rich snack. [Copyright &y& Elsevier]

Abstract: The Modified Uniform Oil Colour Scale (MUOCS) is proposed for the colour specification of virgin olive oils. MUOCS has 60 standard colours, the same number as the two previous scales available for the same purpose: Uniform Oil Colour Scale (UOCS) and Bromthymol Blue (BTB). A remarkable improvement in accuracy can be achieved from MUOCS standards: For a broad dataset of 1700 virgin olive oils produced in Spain during four different harvests, the average colour differences to the closest standards were 2.86, 3.99, and 8.17 CIELAB units using MUOCS, UOCS and BTB, respectively. A low-cost (<60 Euros) portable electronic device is proposed for the colour specification of virgin olive oils based on MUOCS and BTB standards. This device can operate with USB connection to a computer or AAA batteries, and is based on fast (<0.25s) transmittance measurements of the virgin-olive-oil sample placed in a 5-mm pathlength quartz cell. The device may avoid the use of expensive laboratory instrumentation for colour measurement and can be easily employed by non-technician users. For a reduced set of commercial virgin olive oils with random colours, the MUOCS classifications provided by our device agreed with those given by conventional spectrophotometric measurements in 92% of the cases. [Copyright &y& Elsevier]

Abstract: A computer vision system tries to mimic our primary sense (sight) in order to gather information without the need for physical interaction, in fact such systems are able to grade automatically, and extract useful information with a degree of sensitivity closer to that of a human, reducing considerably the margin of error. By performing digital image processing, defined as the acquisition and processing of visual information by computer, computer vision systems allow analyzing image data for specific applications in order to determine how images can be used to extract the required information. Among the most important features for accurate classification and sorting of products it can be mentioned the shape. The shape of objects or regions of interest are important features used for content representation, and require good segmentation to detect objects or regions. Basically, shape characterization is of two types: boundary-based and regionbased. Boundary-based shape features include rectilinear shapes, polygonal approximation, finite element models, and Fourier-based shape descriptors. Region-based features include statistical moments and grid-based approaches. Object shape detection using a technique based on Hough Transform for further segmentation is presented on this paper. [Copyright &y& Elsevier]

Abstract: The aim of the present work was to determine whether there is any relationship between measurement by transmission and reflection (in the latter case, with and without contact with the sample). We also evaluated which methodology used would offer a better interpretation of the results in visual terms. For this purpose, different colorimetric techniques such as transmission spectrophotometry, diffuse reflectance spectrophotometry and spectroradiometry were applied. The samples consisted of increasing dilutions (0, 20, 40, 60, 80 and 100%) of the phenolic fractions obtained from 4 wines: Tempranillo (T) and Graciano (G) monovarietal wines, and two 80:20 mixtures: M (wine elaborated by blending grapes) and W (a blend of the T and G wines) (9 fractions per wine). Fractionation was performed using gel permeation chromatography with a Toyopearl HW-40S column, and the dilutions of the fractions were performed with synthetic wine (pH=3.6). The spectroradiometric measurements permitted the differences due to the dilution effect on the fractions to be established more clearly than with the results obtained using diffuse reflectance and spectrophotometry. Thus, this technology is very suitable for use in comparative interpretations by the human eye. In turn, we assessed the changes in colour due to the effect of dilution on the fractions, observing that the effect of dilution led to an increase in the values of lightness (L*), while the chroma values (C*ab) followed the opposite trend, in agreement with its role as a variable related to chromatic intensity or vividness of the sample. In contrast, hue (hab) did not seem to be affected by dilution of the fractions, in consonance with the qualitative nature of this parameter. [Copyright &y& Elsevier]

Abstract: In the present study, we have identified pelargonidin 3-glucoside, along with two known anthocyanin; cyanidin 3-sophoroside and cyanidin 3-glucoside, from acidified, methanolic extract of mangosteen pericarp. The compounds were separated by preparative HPLC after purification by partition against ethyl acetate and Amberlite XAD-7. The structures of the compounds were confirmed by high performance liquid chromatography (HPLC), UV–Vis absorption spectra, high-resolution electrospray mass spectrometry and 1D, 2D nuclear magnetic resonance (NMR) spectroscopy. This new pigment family adds to the growing body of data supporting the use of natural colourants in food. Cyanidin 3-sophoroside was the major anthocyanin detected in large amount (76.1%), followed by cyanidin 3-glucoside (13.4%) and pelargonidin 3-glucoside (6.2%). [Copyright &y& Elsevier]