Home About us Contact
|
Home About us Contact | ||
|
|
||
Color Differences (color + difference)
Selected AbstractsProduction and Shelf Stability of Multiple-Fortified Quick-Cooking Rice As a Complementary FoodJOURNAL OF FOOD SCIENCE, Issue 7 2008S. Porasuphatana ABSTRACT:, Rice-based complementary foods normally contain inadequate amounts of several micronutrients, such as iron, calcium, and zinc. This study aimed at improving the quality of commercially produced rice-based complementary foods. The analysis centered on identifying a rice-based complementary food that is safe, stable, sensory acceptable, and economical in terms of fortificants (iron, calcium, zinc, thiamine, folate) and effectively packaged for industrial production and distribution. Product colors were mostly in green-yellow tone and slightly changed to more yellow during storage. Sensory acceptability was affected by changes in odor and rancidity but not in color. Rancidity scores were low in aluminum foil laminated plastic bags (ALU). Lipid oxidation significantly increased during storage, but at a slower rate when sodium citrate and ALU were used. Color differences of raw products were detected but not in the cooked ones. Mineral and vitamin losses during processing were 2% to 11% and 20% to 30%, respectively, but no losses were found during storage. FeSO4+ NaFeEDTA added with sodium citrate resulted in the most acceptable product for all packagings. The multiple-fortified quick-cooking rice (MFQCR) developed from this study could be a potentially useful tool for combating micronutrient deficiencies among infants and young children in the countries where rice is the staple food. [source] Retention of Folate, Carotenoids, and Other Quality Characteristics in Commercially Packaged Fresh SpinachJOURNAL OF FOOD SCIENCE, Issue 9 2004S. Pandrangi ABSTRACT: The effect of storage temperature (4 °C, 10 °C, and 20 °C) on retention of folate, carotenoids, and other quality characteristics in commercially packaged fresh spinach were determined. Based on visual color and appearance, spinach was unacceptable after 8 d, 6 d, and 4 d at 4 °C, 10 °C, and 20 °C, respectively. Color differences (AE), chlorophyll degradation, fresh weight loss, and microbial populations increased at all storage temperatures and occurred more rapidly at higher temperatures. Peroxidase activity increased but was not significantly (P > 0.05) affected by storage temperature. Lipoxygenase activity was unaffected by storage time or temperature. Substantial losses of nutrients occurred at each storage temperature. Only 53% of folate in packaged spinach was retained after 8 d, 6 d, and 4 d at 4 °C, 10 °C, and 20 °C, respectively. Carotenoid losses increased with temperature with only 54%, 61%, and 44%, respectively, of initial detected levels remaining. Vitamin and quality changes were unaffected by presence or absence of packaging. [source] Effect of surface conditions on the color of dental resin compositesJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 5 2002Yong-Keun Lee Abstract The objectives of this study were to evaluate the effect of surface conditions of dental resin composites on the measured color depending on the measuring geometry (SCE, SCI), and to determine the color difference (,E*) caused by varied surface conditions. Color and surface roughness (Ra) of five brands of resin composites of A2 shade were measured after polymerization and polishing with 600-, 1000-, or 1500-grit SiC paper. Color was measured according to the CIE L*a*b* color scale. ,E* between different surface conditions was calculated by the equation ,E* = [(,L*)2 + (,a*)2 + (,b*)2]1/2. Before polishing, CIE L* values with the SCE were significantly lower than those measured with the SCI. Before polishing, ,E* values depending on the measuring geometry were very high (3.78,5.93). However, those after polishing were lower than 1.61. CIE L* values increased after polishing (p < 0.05) with the SCE; however, they were not changed with the SCI. ,E* values between Mylar-covered and 600-grit polished specimens were 4.20,5.99 with the SCE and 0.27,1.46 with the SCI. Measurement with the SCE geometry may result in accurate color determination, which reflects the surface conditions of dental restorative materials. ,E* values measured with the SCE between the specimens of different surface conditions were significantly higher than those with the SCI (p < 0.05). © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 657,663, 2002 [source] Influence of cosurfactant in microemulsion systems for color removal from textile wastewaterJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 1 2005Leocadia Terezinha Cordeiro Beltrame Abstract Microemulsion systems have proved very efficient in color removal from textile wastewater using n -butyl alcohol as cosurfactant. The cosurfactant has a very important role in microemulsified systems, as it is responsible for their stability, mainly in systems formed by ionic surfactants. Although very efficient, n -butyl alcohol is partially soluble in water, which would permit its passage to the effluent. In this work, isoamyl and octyl alcohols, due to their lower solubility in water, were used as cosurfactants to evaluate their influence in color removal. The colorimetry system used was the CIE L*a*b* (CIELAB) color space and CIE L*a*b* color difference (,E*ab). The wastewater used in this study was the reactive exhausted dye liquor from a dye house (first discharge) containing Procion Yellow H-E4R (CI Reactive Yellow 84), Procion Blue H-ERD (CI Reactive Blue 160) and Procion Red H-E3B (CI Reactive Red 120). The obtained results were modeled using an experimental planning (the Scheffé net) and evaluated through isoresponse diagrams by correlation graphs between experimental values and those obtained by the models with an error lower than 4%. All the optimized systems were very efficient and more than 94% of the dyes contained in the effluent were removed. The microemulsion load capacity was determined using a synthetic solution containing, the same dyes present in the reactive exhausted dyebath, but 200 times concentrated, and the dyes extraction was more than 99.6%. By comparing n -butyl, isoamyl and octyl alcohols, it was observed that the system using isoamyl alcohol presented slightly better color removal and much higher load capacity than the n -butyl and octyl alcohols. Copyright © 2004 Society of Chemical Industry [source] Use of microemulsions for removal of color and dyes from textile wastewaterJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 6 2004Tereza Neuma de Castro Dantas Abstract One of the major environmental problems in the textile dyeing industry is the removal of color from effluents. The present study deals with color removal from effluents using microemulsions. The wastewater used in this study was the reactive exhausted dye liquor from a dyeing house containing Procion Yellow H-E4R (CI Reactive Yellow 84), Procion Blue H-ERD (CI Reactive Blue 160) and Procion Red H-E3B (CI Reactive Red 120). Color removal was determined by CIEL*a*b* (CIELAB) color space, CIEL*a*b* color difference, ,E*ab, and absorbance. Color removal greater than 95% was achieved, attaining values lower than the consent requirements established by the Environmental Agency. It was observed that pH is an important parameter in color removal and effluent pH correction from 10.44 to 9 before extraction improved results. The results obtained were modeled using the Scheffé net method and evaluated through the construction of isoresponse diagrams by correlation graphics between experimental values and those obtained through use of model equations, providing an experimental error of less than 2%. The optimized method very efficiently removed all dyes contained in the effluent. The same microemulsion phase recovered after the extraction process can be used at least a further 14 times and all the extractions gave good color removal. Copyright © 2004 Society of Chemical Industry [source] Spectrophotometric Analysis of Tooth Color Reproduction on Anterior All-Ceramic Crowns: Part 2: Color Reproduction and Its Transfer from In Vitro to In VivoJOURNAL OF ESTHETIC AND RESTORATIVE DENTISTRY, Issue 1 2010AKI YOSHIDA RDT ABSTRACT Color reproduction of an anterior tooth requires advanced laboratory techniques, talent, and artistic skills. Color matching in a laboratory requires the successful transfer from in vivo with careful considerations. The purpose of this study was to monitor and verify the color reproduction process for an anterior all-ceramic crown in a laboratory through spectrophotometric measurements. Furthermore, a crown insertion process using composite luting cements was assessed, and the final color match was measured and confirmed. An all-ceramic crown with a zirconia ceramic coping for the maxillary right central incisor was fabricated. There was a significant color difference between the prepared tooth and the die material. The die material selected was the closest match available. The ceramic coping filled with die material indicated a large color difference from the target tooth in both lightness and chromaticity. During the first bake, three different approaches were intentionally used corresponding with three different tooth regions (cervical, body, and incisal). The first bake created the fundamental color of the crown that allowed some color shifts in the enamel layer, which was added later. The color of the completed crown demonstrated an excellent color match, with ,E 1.27 in the incisal and 1.71 in the body. In the cervical area, color match with ,E 2.37 was fabricated with the expectation of a color effect from the underlying prepared tooth. The optimal use of composite luting cement adjusted the effect from the underlying prepared tooth color, and the color match fabricated at a laboratory was successfully transferred to the clinical setting. The precise color measurement system leads to an accurate verification of color reproduction and its transfer. CLINICAL SIGNIFICANCE The use of a dedicated dental spectrophotometer during the fabrication of an all-ceramic crown allows the dentist and the laboratory technician to accurately communicate important information to one another about the shade of the tooth preparation, the shade of the contralateral target tooth, and the influence of luting cement on the final restoration, thereby allowing the technician better control over the outcome of their tooth color matching efforts and the final color match of an all-ceramic restoration. (J Esthet Restor Dent 22:53,65, 2010) [source] New Shade Guide for Evaluation of Tooth Whitening,Colorimetric StudyJOURNAL OF ESTHETIC AND RESTORATIVE DENTISTRY, Issue 5 2007RADE D. PARAVINA DDS ABSTRACT Statement of the Problem:, Available shade guides lack colorimetric uniformity, which compromises the validity of visual evaluation of tooth whitening efficacy. Purpose:, The objective of this study was to perform a colorimetric analysis of a new shade guide designed primarily for the visual evaluation of tooth whitening efficacy and to compare this shade guide with two commercial shade guides. Materials and Methods:, Color ranges and color distribution of three shade guides (prototype of the new Vita Bleachedguide 3D-Master [BG, Vita Zahnfabrik, Bad Säckingen, Germany], value scale of Vitapan Classical [VC, Vita], and color-ordered Trubyte Bioform porcelain shade guide [TB, Dentsply International, York, PA, USA]) were analyzed (N=3). A circular area (d=1.7 mm) on the middle of the labial surface of the tab, excluding the cervical portion, was measured with a spectroradiometer (D65, 2). Whiteness and yellowness indices were computed. Data were analyzed by analysis of variance and Fisher's PLSD test at a 0.05 level of significance. Results:, The range of color difference (,E*) from the lightest to the darkest tab was 33.8 (BG), 17.1 (VC), and 23.2 (TB). Mean values of ,E* among pairs of adjacent tabs were 3.0 (BG), 4.2 (VC), and 3.3 (TB). BG exhibited the highest R2 values between color coordinate pairs and between whiteness and yellowness indices with the respective color coordinates. Conclusions:, BG exhibited the widest color range and had the most consistent color distribution as compared with the two commercial products. Extension of the lightness range of BG toward higher L* values (bleach shades) was confirmed. CLINICAL SIGNIFICANCE A dental shade guide that is colorimetrically uniform might increase the reliability of visual comparisons of tooth whitening efficacy, whereas the inclusion of realistic bleaching shades in the shade guide will complement contemporary esthetic dentistry. (J Esthet Restor Dent 19:276,283, 2007) [source] RESPONSE SURFACE METHODOLOGY FOR STUDYING THE QUALITY CHARACTERISTICS OF COWPEA (VIGNA UNGUICULATA)-BASED TEMPEHJOURNAL OF FOOD PROCESS ENGINEERING, Issue 4 2010GEORGE AMPONSAH ANNOR ABSTRACT Response surface methodology was used to optimize the processing conditions in the preparation of cowpea tempeh. The independent factors studied were boiling time (varying from 5 to 30 min), incubation time (varying from 12 to 48 h) and incubation temperatures (varying from 25 to 50C), whereas the dependent factors were protein content, protein solubility, pH, titratable acidity and total color difference (using L, a* and b*). Regression models were generated and adequacy was tested with regression coefficients (R2) and the lack-of-fit tests. Optimum processing conditions were determined by method of superimposition. There was a strong and significant influence (P < 0.01) of the quadratic effect of the incubation time on the protein content of the cowpea tempeh, with similar significance (P < 0.01) noted in protein solubility with increasing boiling time. The optimum processing conditions observed for the preparation of cowpea tempeh were boiling time of about 20 min, incubation time of about 28 h and incubation temperature of about 37C. PRACTICAL APPLICATIONS Response surface methodology (RSM), as a statistical tool, has been effectively used in food process applications. This study embraced the use of RSM in the optimization of the processing conditions involved in the preparation of cowpea tempeh. Superimposition of the contour plots developed from the regression models indicated that cowpea with optimum quality characteristics should be processed at a boiling time of 20 min, incubation time of 28 h and incubation temperature of 37C. These conditions could be adopted for the industrial production of cowpea tempeh. [source] PHYSICAL, PHYSIOLOGICAL AND CHEMICAL CHANGES IN POTATO AS INFLUENCED BY ERWINIA CAROTOVORA INFECTIONJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 5 2002F. NOURIAN Bacterial soft rot, caused by Erwinia carotovora ssp. carotovora (Ecc), is a major disease in stored potatoes. The pathogen causes different physical, physiological and chemical changes in potatoes, which may affect the acceptability of raw and processed products. This study was carried out to evaluate the effect of disease severity on different physico-chemical and physiological properties of raw and cooked potatoes and to select the parameters most responsive to disease severity. Potatoes were inoculated with bacteria and incubated at 20C for different lengths of time to produce different levels of disease. As incubation time increased the volume of disease (VDS) increased, which in turn influenced the respiration rate (RR). In both raw and cooked potatoes, the physical changes (texture and color) associated with the progress of disease were reduced hardness, firmness and L value, and increased a and b values and total color difference (,E). The chemical changes were reduced ascorbic acid and pH, and increased reducing sugars, total sugars and titrable acidity along with the activities of peroxidase and polyphenol oxidase. The changes in physical and chemical parameters of raw and cooked potatoes during storage were described by fractional conversion equation models. All parameters were quite sensitive to disease except reducing sugars, peroxidase and PPO activity. The correlation matrix indicated that several of the quality parameters were related and thus most of them could be successfully used to predict tuber quality from disease. [source] Color distribution of maxillary primary incisors in Korean childrenCOLOR RESEARCH & APPLICATION, Issue 2 2010Hong-Keun Hyun Abstract The purpose of this study was to investigate the color distribution of maxillary primary incisors measured with a colorimeter. The subjects were 100 Korean children aged 2,5 with total number of 400 teeth. A spot measurement intraoral colorimeter was used to determine the color of maxillary primary central and lateral incisors at labial central area. The CIE L*, a*, b* value of each tooth and color difference (,E) among each other were calculated and analyzed. The range of L*, a*, and b* values, regardless of the type of teeth, was 72.7,84.9, ,0.6 to 4.9, and 4.7,15.0, respectively. Mean value (SD) of L*, a*, and b* for maxillary primary incisors was 78.6 (2.3), 1.2 (0.9), and 9.6 (1.8), respectively. Boys showed more red (higher a* value) and less yellow (lower b* value) hue than girls in the central incisors (P < 0.05). Mean color difference (,E) (SD) between two values which selected from overall 400 L*, a*, b* values measured (n = 400C2) was 3.9 (1.8) with 95% confidence interval range of 3.86,3.89, and most of them were found to be present around the previously reported clinical acceptability thresholds (,E = 2.7,6.8). Because mean intraperson ,E (SD) was 3.0 (1.6) with 95% confidence interval range of 2.86,3.12, most colors among primary incisors in the same person were presumably difficult to discern by naked eye (,E < 3.7). Age influenced L* and b* values significantly, but the correlation coefficients were not high (r = ,0.182 for L* of central incisors, P < 0.01; r = 0.188 for b* of central incisors, P < 0.01; and r = 0.143 for b* of lateral incisors, P < 0.05). The present study showed somewhat higher color coordinates than the previous reports which based on primary anterior teeth in other ethnic groups. The results of this study could be used for the color modification of esthetic materials for primary teeth. © 2009 Wiley Periodicals, Inc., Col Res Appl, 2010. [source] Spectral color reproduction minimizing spectral and perceptual color differencesCOLOR RESEARCH & APPLICATION, Issue 6 2008Jérémie Gerhardt Abstract In this article, we are combining minimization criteria in the colorant separation process for spectral color reproduction. The colorant separation is performed by inverting a spectral printer model: the spectral Yule-Nielsen modified Neugebauer model. The inversion of the spectral printer model is an optimization operation in which a criterion is minimized at each iteration. The approach we proposed minimizes a criterion defined by the weighted sum of a spectral difference and a perceptual color difference. The weights can be tuned with a parameter , , [0, 1]. Our goal is to decrease the spectral difference between the original data and its reproduction and also to consider perceptual color difference under different illuminant conditions. In order to find the best , value, we initially compare a pure colorimetric criterion and a pure spectral criterion for the reproduction, then we combine them. We perform four colorant separations: the first separation will minimize the 1976 CIELAB color difference where four illuminants are tested, the second separation will minimize an equally weighted summation of 1976 CIELAB color difference with the four illuminants tested independently, the third colorant separation will minimize a spectral difference, and the fourth colorant separation will combine a weighted sum of a spectral difference and one of the two first colorimetric differences previously introduced. This last colorant separation can be tuned with a parameter in order to emphasize on spectral or colorimetric difference. We use a six colorants printer with artificial inks for our experiments. The prints are simulated by the spectral Yule-Nielsen modified Neugebauer model. Two groups of data are used for our experiments. The first group describes the data printed by our printing system, which is represented by a regular grid in colorant space of the printer and the second group describes the data which is not originally produced by our printing system but mapped to the spectral printer gamut. The Esser test chart and the Macbeth Color Checker test chart have been selected for the second group. Spectral gamut mapping of this data is carried out before performing colorant separation. Our results show improvement for the colorant separations combining a sum of 1976 CIELAB color difference for a set of illuminants and for the colorant separation combining a sum of 1976 CIELAB color difference and spectral difference, especially in the case of spectral data originally produced by the printer. © 2008 Wiley Periodicals, Inc. Col Res Appl, 33, 494,504, 2008 [source] Dominance, Status Signals and Coloration in Male Mandrills (Mandrillus sphinx)ETHOLOGY, Issue 1 2005Joanna M. Setchell Where individuals contest access to a resource, escalated physical fighting presents a risk to all involved. The requirement for mechanisms of conflict management has led to the evolution of a variety of decision rules and signals that act to reduce the frequency of aggression during competitive encounters. We examined strategies of conflict management in male mandrills (Mandrillus sphinx) living in two semi-free-ranging groups in Gabon. Adult male mandrills are large (31 kg), with long canines, making the costs of conflict potentially very high. We found that males formed dominance hierarchies, but that male,male relationships were characterized by avoidance, appeasement and ignoring. Fights were rare, but could result in death. Examination of the relationship between dominance and signaling showed that males use facial and gestural signals to communicate dominance and subordinance, avoiding escalated conflict. Male mandrills also possess rank-dependent red coloration on the face, rump and genitalia, and we examined the hypothesis that this coloration acts as a ,badge of status', communicating male fighting ability to other males. If this is the case, then similarity in color should lead to higher dyadic rates of aggression, while males that differ markedly should resolve encounters quickly, with the paler individual retreating. Indeed, appeasement (the ,grin' display), threats, fights and tense ,stand-off' encounters were significantly more frequent between similarly colored males, while clear submission was more frequent where color differences were large. We conclude that male mandrills employ both formal behavioral indicators of dominance and of subordination, and may also use relative brightness of red coloration to facilitate the assessment of individual differences in fighting ability, thereby regulating the degree of costly, escalated conflict between well-armed males. [source] ADAPTIVE REPTILE COLOR VARIATION AND THE EVOLUTION OF THE MCIR GENEEVOLUTION, Issue 8 2004Erica Bree Rosenblum Abstract The wealth of information on the genetics of pigmentation and the clear fitness consequences of many pigmentation phenotypes provide an opportunity to study the molecular basis of an ecologically important trait. The melanocortin-1 receptor (Mc1r) is responsible for intraspecific color variation in mammals and birds. Here, we study the molecular evolution of Mc1r and investigate its role in adaptive intraspecific color differences in reptiles. We sequenced the complete Mc1r locus in seven phylogenetically diverse squamate species with melanic or blanched forms associated with different colored substrates or thermal environments. We found that patterns of amino acid substitution across different regions of the receptor are similar to the patterns seen in mammals, suggesting comparable levels of constraint and probably a conserved function for Mc1r in mammals and reptiles. We also found high levels of silent-site heterozygosity in all species, consistent with a high mutation rate or large long-term effective population size. Mc1r polymorphisms were strongly associated with color differences in Holbrookia maculata and Aspidoscelis inornata. In A. inornata, several observations suggest that Mc1r mutations may contribute to differences in color: (1) a strong association is observed between one Mc1r amino acid substitution and dorsal color; (2) no significant population structure was detected among individuals from these populations at the mitochondrial ND4 gene; (3) the distribution of allele frequencies at Mc1r deviates from neutral expectations; and (4) patterns of linkage disequilibrium at Mc1r are consistent with recent selection. This study provides comparative data on a nuclear gene in reptiles and highlights the utility of a candidate-gene approach for understanding the evolution of genes involved in vertebrate adaptation. [source] EVOLUTION OF COLOR VARIATION IN DRAGON LIZARDS: QUANTITATIVE TESTS OF THE ROLE OF CRYPSIS AND LOCAL ADAPTATIONEVOLUTION, Issue 7 2004Devi M. Stuart-Fox Abstract Many animal species display striking color differences with respect to geographic location, sex, and body region. Traditional adaptive explanations for such complex patterns invoke an interaction between selection for conspicuous signals and natural selection for crypsis. Although there is now a substantial body of evidence supporting the role of sexual selection for signaling functions, quantitative studies of crypsis remain comparatively rare. Here, we combine objective measures of coloration with information on predator visual sensitivities to study the role of crypsis in the evolution of color variation in an Australian lizard species complex (Ctenophorus decresii). We apply a model that allows us to quantify crypsis in terms of the visual contrast of the lizards against their natural backgrounds, as perceived by potential avian predators. We then use these quantitative estimates of crypsis to answer the following questions. Are there significant differences in crypsis conspicuousness among populations? Are there significant differences in crypsis conspicuousness between the sexes? Are body regions "exposed" to visual predators more cryptic than "hidden" body regions? Is there evidence for local adaptation with respect to crypsis against different substrates? In general, our results confirmed that there are real differences in crypsis conspicuousness both between populations and between sexes; that exposed body regions were significantly more cryptic than hidden ones, particularly in females; and that females, but not males, are more cryptic against their own local background than against the background of other populations. Body regions that varied most in contrast between the sexes and between populations were also most conspicuous and are emphasized by males during social and sexual signaling. However, results varied with respect to the aspect of coloration studied. Results based on chromatic contrast ("hue' of color) provided better support for the crypsis hypothesis than did results based on achromatic contrast ("brightness' of color). Taken together, these results support the view that crypsis plays a substantial role in the evolution of color variation and that color patterns represent a balance between the need for conspicuousness for signaling and the need for crypsis to avoid predation. [source] Shade darkening effect of polyorganosiloxane modified with amino and hydroxy groups on dyed polyester microfiber fabricJOURNAL OF APPLIED POLYMER SCIENCE, Issue 2 2007Kongliang Xie Abstract The novel polyorganosiloxane material S-101 modified with amino and hydroxy groups is synthesized. Shade darkening effect of modified polyorganosiloxane on dyed polyester microfiber fabric is investigated by reflectance spectrum, color yield (K/S), and the color differences (,E). The colorimetric data of CIELAB is discussed. The results show that the novel material of silicone polymer modified with amino and hydroxy groups has excellent shade darkening effect on dyed polyester microfiber fabric. The rates of the color yield increase (I%) of all dyed fabric with four dyes (Disperse Yellow S-4RL, Red GS, Blue 2BLN, and Black SF-R) exceed 10%. The shapes of the reflectance spectra curves of the dyed fabrics before and after treated with S-101 are not noticeable change. The dyed fabrics with the polymer have not significant effect on the wash fastness and wet rubbing fastness. The low reflectance thin film on dyed fabrics is formed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 [source] Color characteristics of low-chroma and high-translucence dental resin composites by different measuring modesJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 6 2001Yong-Keun Lee Abstract The objective of the described research was the evaluation of the effects of the differences in the color-measuring geometry (SCE, SCI) and the standard illuminant on the color and color change after polymerization and thermocycling of resin composites. White, translucent, and conventional shades of two brands of resin composites were measured before and after polymerization and after thermocycling according to the CIE L*a*b* color scale on a reflection spectrophotometer with SCE and SCI geometry under the standard illuminants A, D65, and C. Under both SCE and SCI modes, the color differences (,E*) of specimens between the values measured under illuminants A and D65 or A and C were larger than those between D65 and C in unpolymerized, polymerized, and thermocycled conditions. With SCE geometry, ,E* after polymerization of the white shade group was 8.7,9.8 under D65, and was higher than the conventional shade group (p < 0.05) in both materials. With SCE geometry, ,E* between polymerized and thermocycled white, translucent shade was 4.4,7.1 under D65. With SCI geometry, the results were in general agreement with those of SCE mode. After polymerization, ,E* measured under illuminant A was generally higher than that under D65 or C (p < 0.01). After thermocycling, the color change was different depending on the color-measuring geometry and standard illuminant. © 2001 John Wiley & Sons, Inc. J Biomed Mater Res (Appl Biomater) 58: 613,621, 2001 [source] Influence of Visual Masking Technique on the Assessment of 2 Red Wines by Trained and Consumer AssessorsJOURNAL OF FOOD SCIENCE, Issue 6 2008C.F. Ross ABSTRACT:, During sensory evaluation assessments, visual masking techniques are frequently employed to disguise color differences between samples and minimize perceptual bias. Particularly in wine, the impact of these masking techniques on panelist evaluations has not been well studied. The objective of this study was to study the influence of visual masking techniques on the aroma and flavor assessment of 2 red wines and observe the impact of these techniques on trained and consumer sensory panels. Specific masking techniques included (1) blue wine glass/white illumination; (2) clear glass/red illumination; and (3) clear glass/white illumination. Ten panelists were trained to recognize 7 aroma and flavor attributes, while consumer panelists (n= 80) evaluated attributes and liking. For the trained panel, the visual masking technique affected only perceived spicy flavor of Syrah (P, 0.05), with the clear glass/red illumination resulting in more intense spicy flavor compared to the other 2 conditions. Principal components analysis showed that for the 2 red wines evaluated by the trained panel, red illumination resulted in higher spicy attributes and perceived astringency while wines served in blue wine glasses were higher in perceived astringency. For the consumer panel, red illumination resulted in wines higher in perceived astringency and blue wine glasses resulted in wines higher in perceived flavor liking. These results indicated that the visual masking techniques may influence both trained and consumer panel evaluation of aroma and flavor attributes of red wine. However, beyond red wine, this study makes the larger point that the choice of masking technique does impact sensory evaluations. [source] Color Separation in Forensic Image ProcessingJOURNAL OF FORENSIC SCIENCES, Issue 1 2006Charles E. H. Berger Ph.D. ABSTRACT: In forensic image processing, it is often important to be able to separate a feature from an interfering background or foreground, or to demonstrate colors within an image to be different from each other. In this study, a color deconvolution algorithm that could accomplish this task is described, and it is applied to color separation problems in document and fingerprint examination. Subtle color differences (sometimes invisible to the naked eye) are found to be sufficient, which is demonstrated successfully for several cases where color differences were shown to exist, or where colors were removed from the foreground or background. The software is available for free in the form of an Adobe® Photoshop® -compatible plug-in. [source] Performance of Five Commercially Available Tooth Color-Measuring DevicesJOURNAL OF PROSTHODONTICS, Issue 2 2007Alma Dozi Purpose: Visual tooth color assessment is neither accurate nor precise due to various subjective and objective factors. As newly developed tooth color-measuring devices for dental application provide the possibility of a more objective means of color determination, their performances in vitro and in vivo must be evaluated. The objective of this study was to evaluate the accuracy and precision of five commercially available tooth color-measuring devices in standardized and in clinical environments. Materials and Methods: In an in vitro study, standards (A1, A2, A3, A3.5, and A4 shade tabs of Vita Lumin) were measured five times with five electronic devices (ShadeScan, Easyshade, Ikam, IdentaColor II, and ShadeEye) by two operators. In an in vivo study, the right upper central incisors of 25 dental students were measured with the same electronic devices by a single operator. Vita shade tab codes were expressed as CIE (International Commission on Illumination) L*a*b* values and in terms of the precision and accuracy of ,E color differences. The Mann-Whitney statistical test was used to analyze the differences between the two operators in the in vitro study, and the Kruskal-Wallis one-way analysis of variance on ranks with the post-hoc Tukey test was used to analyze the accuracy and precision of electronic devices. Results: No statistically significant difference was found between the different operators in the in vitro study. The obtained precision was Easyshade > ShadeScan , Ikam > IdentaColor II > ShadeEye. The obtained accuracy was Easyshade > ShadeScan , Ikam > ShadeEye > IdentaColor II. In the in vivo study, the Easyshade and the Ikam were the most precise, and the ShadeEye and the IdentaColor II were more precise than the ShadeScan. With respect to accuracy, there was no statistical difference between the ShadeScan, Ikam, and the Easyshade. The IdentaColor II was considered inaccurate (,Ea= 3.4). Conclusions: In the clinical setting, the Easyshade and Ikam systems were the most reliable. The other devices tested were more reliable in vitro than in vivo. [source] Impact of Background on Color Performance of False Clownfish, Amphiprion ocellaris, CuvierJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 6 2009Inayah Yasir Color performance of false clownfish, Amphiprion ocellaris, Cuvier was first examined at four color backgrounds (blue, green red, and white) for 4 wk, then all fish were transferred to a white background for another 4 wk to test whether the impact of background colors on fish skin could have a lasting effect when the environment colors are changed. The experiment was conducted in 10-L rectangular plastic buckets with three replicates. Thirty fish were stocked in each bucket and three fish were randomly sampled from each tank in Weeks 1, 4, and 8. The color hue, saturation, and brightness were quantified using image analysis. In addition to the whole body analysis, each fish image was divided into ventral and dorsal parts to examine the body position-dependent response. Furthermore, color differences among the dorsal fin, anal fin, ventral fin, and caudal fin were also quantified. Blue or green background enhanced red orange color on fish skin, whereas white background made fish color brighter. Irrespective of background color, the dorsal side of fish exhibited more red orange, but the color was less bright and less saturated than that of ventral side. Upper fins (dorsal and caudal fins) were more red orange in a blue background than in a white background. Transferring fish from colored backgrounds to a white background made the fish skin and fins brighter, the color of ventral body and ventral fins less saturated, and the bottom fins more yellow orange. The results indicate that blue or green background could strengthen the orange color, whereas white background made fish color less saturated but brighter. The impact of background on the performance of fish color is temporary and likely to disappear when environmental color changes. [source] Effect of Light Intensity on Color Performance of False Clownfish, Amphiprion ocellaris CuvierJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 3 2009Inayah Yasir Color performance of false clownfish, Amphiprion ocellaris Cuvier, was examined under three levels of light intensity (20,50 , 600,850 , and 2700,3500 lx) for 5 wk. The experiment was conducted in nine rectangular glass aquaria (25 × 25 × 20 cm) with three replicates. Each aquarium was stocked with 36 fish, and 3 fish were randomly sampled from each aquarium every other week. Digital images were taken weekly on each individual fish after it was anesthetized in MS-222. The color performance in hue, saturation, and brightness was quantified using image analysis. In addition to the whole-body analysis, each fish image was divided into ventral and dorsal parts to assess the body position-dependent effect. Furthermore, color differences between dorsal fin, anal fin, ventral fin, and caudal fin were also quantified. The whole body was brighter at low light than at medium or at high light intensity. Irrespective of light intensity, the dorsal side was more orange but less bright than the ventral side. Brighter light strengthened overall orange color on fish fins. The dorsal fin and ventral fins appeared more orange than the anal and caudal fins regardless of light intensity and exposure duration. Similar to body color, low light also led to brighter fins, especially for caudal and dorsal fins. Our results indicate that ambient light could regulate fish color performance but could not change the pigment dominance by ,-carotene. Light intensity is unlikely to change the contrast between dorsal and ventral sides, but dim light tends to make fish body brighter, and bright light strengthens orange color on fins. [source] Floral color patterns in a tropical orchid: Are they associated with reproductive success?PLANT SPECIES BIOLOGY, Issue 2 2007RAYMOND L. TREMBLAY Abstract We sought to measure phenotypic selection on petal color variation in populations of Lepanthes rupestris, a diminutive epilithic orchid of Puerto Rico that exhibits a polymorphism in petal color patterns (unicolor or bicolored). We censused seven populations monthly for 20 months and noted flower production and petal color pattern. Each flower was checked for pollinarium removal (male fitness measure) and fruit production (female fitness). In all populations, plants with bicolored petals dominated and comprised 63,82% of individuals. Aside from petal color differences, the two types were indistinguishable. Flower color pattern was generally not associated with either male or female reproductive success within or among populations or over time. Environmental conditions, rainfall and humidity, may account for both temporal and spatial variation in the reproductive success observed among sites. Although we were unable to tag fitness to petal color patterns, the consistent ratio of color morphs among populations suggests that factors other than just drift are responsible for the frequencies we observed. [source] Brief communication: Blue eyes in lemurs and humans: Same phenotype, different genetic mechanismAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 2 2009Brenda J. Bradley Abstract Almost all mammals have brown or darkly-pigmented eyes (irises), but among primates, there are some prominent blue-eyed exceptions. The blue eyes of some humans and lemurs are a striking example of convergent evolution of a rare phenotype on distant branches of the primate tree. Recent work on humans indicates that blue eye color is associated with, and likely caused by, a single nucleotide polymorphism (rs12913832) in an intron of the gene HERC2, which likely regulates expression of the neighboring pigmentation gene OCA2. This raises the immediate question of whether blue eyes in lemurs might have a similar genetic basis. We addressed this by sequencing the homologous genetic region in the blue-eyed black lemur (Eulemur macaco flavifrons; N = 4) and the closely-related black lemur (Eulemur macaco macaco; N = 4), which has brown eyes. We then compared a 166-bp segment corresponding to and flanking the human eye-color-associated region in these lemurs, as well as other primates (human, chimpanzee, orangutan, macaque, ring-tailed lemur, mouse lemur). Aligned sequences indicated that this region is strongly conserved in both Eulemur macaco subspecies as well as the other primates (except blue-eyed humans). Therefore, it is unlikely that this regulatory segment plays a major role in eye color differences among lemurs as it does in humans. Although convergent phenotypes can sometimes come about via the same or similar genetic changes occurring independently, this does not seem to be the case here, as we have shown that the genetic basis of blue eyes in lemurs differs from that of humans. Am J Phys Anthropol, 2009. © 2009 Wiley-Liss, Inc. [source] Assessing the color of red wine like a taster's eyeCOLOR RESEARCH & APPLICATION, Issue 2 2009Begoña Hernández Abstract Color of 33 commercial red wines and five-color reference wines was measured in the same conditions in which visual color assessment is done by wine tasters. Measurements were performed in the two distinctive regions, center and rim, which are the regions assessed by wine tasters when the wine sampler is tilted. Commercial wines were classified into five color categories using the color specifications in their taste cards. The five color categories describe the spread of red hues found in red wines from the violet to brown nuances. The performance of CIELAB color coordinates in terms of their ability to reproduce the observed classification has been established using discriminant analysis. The CIELAB hue angle, hab, measured in the rim, where wine thickness is of the order of few millimeters, gives the best results classifying correctly 71.1% of the samples. Classification results are not significantly improved when additional color coordinates are considered. Moreover, ,E* color differences with color reference wines do not provide good classification results. The analysis of reference and commercial wines supports the fact that hue is the main factor in the classification done by wine tasters. This is reinforced by the linear correlation found between hab in the rim and the wine age (R2 = 0.795) in accordance with the fact that wines change their hues from violet to brown tints with ageing. © 2009 Wiley Periodicals, Inc. Col Res Appl, 34, 153,162, 2009 [source] Spectral color reproduction minimizing spectral and perceptual color differencesCOLOR RESEARCH & APPLICATION, Issue 6 2008Jérémie Gerhardt Abstract In this article, we are combining minimization criteria in the colorant separation process for spectral color reproduction. The colorant separation is performed by inverting a spectral printer model: the spectral Yule-Nielsen modified Neugebauer model. The inversion of the spectral printer model is an optimization operation in which a criterion is minimized at each iteration. The approach we proposed minimizes a criterion defined by the weighted sum of a spectral difference and a perceptual color difference. The weights can be tuned with a parameter , , [0, 1]. Our goal is to decrease the spectral difference between the original data and its reproduction and also to consider perceptual color difference under different illuminant conditions. In order to find the best , value, we initially compare a pure colorimetric criterion and a pure spectral criterion for the reproduction, then we combine them. We perform four colorant separations: the first separation will minimize the 1976 CIELAB color difference where four illuminants are tested, the second separation will minimize an equally weighted summation of 1976 CIELAB color difference with the four illuminants tested independently, the third colorant separation will minimize a spectral difference, and the fourth colorant separation will combine a weighted sum of a spectral difference and one of the two first colorimetric differences previously introduced. This last colorant separation can be tuned with a parameter in order to emphasize on spectral or colorimetric difference. We use a six colorants printer with artificial inks for our experiments. The prints are simulated by the spectral Yule-Nielsen modified Neugebauer model. Two groups of data are used for our experiments. The first group describes the data printed by our printing system, which is represented by a regular grid in colorant space of the printer and the second group describes the data which is not originally produced by our printing system but mapped to the spectral printer gamut. The Esser test chart and the Macbeth Color Checker test chart have been selected for the second group. Spectral gamut mapping of this data is carried out before performing colorant separation. Our results show improvement for the colorant separations combining a sum of 1976 CIELAB color difference for a set of illuminants and for the colorant separation combining a sum of 1976 CIELAB color difference and spectral difference, especially in the case of spectral data originally produced by the printer. © 2008 Wiley Periodicals, Inc. Col Res Appl, 33, 494,504, 2008 [source] Request for existing experimental datasets on color differencesCOLOR RESEARCH & APPLICATION, Issue 2 2007Manuel Melgosa Abstract The Technical Committee 1-55 of the International Commission on Illumination on "Uniform color space for industrial color difference evaluation" is requesting the submission of datasets for use in developing a new approximately uniform color space for industrial use. The data should be submitted to the TC Chair, Dr. Manuel Melgosa at the University of Granada. © 2007 Wiley Periodicals, Inc. Col Res Appl, 32, 159, 2007 [source] | |||||||||||||||||||