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1
ONUR CINKO, UGUR, and BEHCET BEHCET BECERIR. "Dependence of colour difference formulae on regular changes of colour coordinates in CIELAB colour space." Industria Textila 70, no. 03 (2019): 248–54. http://dx.doi.org/10.35530/it.070.03.1525.
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Four colour difference formulae [CIELAB (1976), CMC (2:1), CIE94 (2:1:1) and CIEDE2000 (2:1:1)] were assessed in CIELAB colour space for regular changes in colour coordinates. L*, a* and b* coordinates were changed regularly both as increasing and decreasing steps in different lightness and hue regions of the colour space. The dependence and consistency of the four formulae were researched depending on regular and constant colour coordinate changes. The aim of the empirical study was to determine if there could be a possibility of using different colour difference formulae in different hue regions of CIELAB colour space; in the region of bulk that each formula would give the best fitting and the most reliable results. The empirical study was carried out by using a special software which was prepared for the purpose. The results showed that CIELAB and CIE94 gave corresponding results with each other in the computing ranges. All the formulae showed different computing characteristics in the computation ranges. CMC formula gave the highest colour differences when computing near the grey point. It was concluded that CIEDE2000 formula suited itself the best according to the changes in computing steps. A more complicated software would be necessary to determine the sensitivity of the formulae by which the computing would be performed by changing all the coordinates (L*, a* and b*) at the same time.
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Gómez-Polo, Cristina, Ana María Martín Casado, Norberto Quispe, Eva Rosel Gallardo, and Javier Montero. "Colour Changes of Acetal Resins (CAD-CAM) In Vivo." Applied Sciences 13, no. 1 (2022): 181. http://dx.doi.org/10.3390/app13010181.
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To quantify the discolouration of the temporary acetal resins in vivo, based on the weeks of follow-up and the salivary pH in the three thirds of the tooth. To find out if the final CIELAB coordinates can be predicted from the initial colour coordinates, the salivary pH, the situation (in thirds) and the weeks of follow-up. Colour coordinates (L, C, and h) were recorded by spectrophotometry in 13 participants fitted with hybrid provisional complete dentures made of acetal resin. Colour recordings were made on the day of placement and after several weeks of follow-up (6 to 31 weeks). Salivary pH was also measured as a predictor variable for colour change. The ANOVA statistical test and regression models have been used. The highest colour difference according to ∆Eab* was 27.46 units after 15 weeks of follow-up and the lowest was 7.34 units after 17 weeks of follow-up. Neither in the cervical nor in the middle third any regressor variable (initial L*, initial C*, initial h*, salivary pH and weeks of follow-up) was able to significantly predict any of the final colour coordinates (p > 0.05). The colour change of the temporary acetal resins used exceeds the threshold of clinical acceptability, and it is not acceptable to maintain satisfactory aesthetics. The weeks of follow-up and the salivary pH are not capable of satisfactorily predicting the final color coordinates of the acetal resins.
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Wei, Xinyi, Stephanie Lam, Benjamin M. Bohrer, et al. "A Comparison of Fresh Pork Colour Measurements by Using Four Commercial Handheld Devices." Foods 10, no. 11 (2021): 2515. http://dx.doi.org/10.3390/foods10112515.
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The objective of this study was to evaluate the performance of different low-cost instruments to measure pork colour in comparison to Minolta spectrophotometers and industry subjective standards. Canadian pork colour standards and commercial meat (252 loin chops and 46 tenderloins) were measured using two Minolta (CM 700D) spectrophotometers, four Nix sensors (two Nix Pro II and two Nix QC), and four Spectro devices (two Spectro 1 and two Spectro 1 Pro). Using Bland-Altman plots, all hand-held devices revealed similar performance on colour coordinates, except for the Nix Pro II, which had more variability on a* value, and Spectro 1 Pro on b* value, when compared to Minolta measurements. Low RSD values (< 5%) were obtained from repeated measurements on Canadian colour standards. The trend of colour coordinates on colour scores (0–6) were similar for all four commercial instruments, except for a* from Nix Pro and b* from Spectro 1. The correlation coefficients between subjective standards and colour coordinates from the Nix and Spectro devices were slightly higher than the Minolta spectrophotometers. Even though Nix and Spectro 1 series instruments generated different absolute colour coordinate values on meat samples, these pocket-size instruments presented great reliability to measure pork surface colour. However, operational limitations of the instruments, such as the internal calibration time between samples for the Spectro 1 series, should also be considered.
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Gómez Polo, Cristina, Yasmina Guadilla, María Portillo Muñoz, et al. "CIELab Colour Coordinate Changes Associated with the Resolution of Gingival Inflammation: Influence of Biotype and Severity." Journal of Clinical Medicine 14, no. 13 (2025): 4575. https://doi.org/10.3390/jcm14134575.
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Background/Objectives: The colour changes related to inflammation have yet to be quantified despite the fact that the intensification of gingival colour is one of the cardinal signs of gingival inflammation. We aimed to (1) assess the effect of periodontal treatment on gingival colour according to biotype and initial degree of inflammatory severity and (2) identify the relationship between the plaque index and gingival colour and compare the colour of moderately or severely inflamed gums to the colour of gums with mild inflammation. Methods: Forty-three participants with visual signs of inflammation were included in the study. CIELAB colour coordinates were measured using a spectrophotometer at the distal papilla, free gingival margin, middle zone of the attached gingiva, and mucogingival line proximate to the maxillary central incisor pre-treatment and four weeks post treatment with periodontal debridement. Each participant’s gingival biotype, plaque and gingival indices, age, and gender were also recorded. Results: The biotype and plaque index were both found to influence the colour of inflamed gums, albeit only the a* coordinate in two of the zones examined (the distal papilla and free gingival margin). Statistically significant differences were also found between the a* coordinates of participants with and without plaque at the distal papilla and the free gingival margin. The severity of inflammation also influenced the L* coordinates of gingival colour (p < 0.001) in all participants in all four zones examined. Periodontal treatment only affected the L* coordinate of gingival colour at the distal papilla and the free gingival margin. Conclusions: When gingival inflammation occurs, participants with thin biotype and plaque have redder gums, and moderately or severely inflamed gingiva have a visually perceptible darker colour. Periodontal treatment significantly increases the lightness of the distal papilla and the free gingival margin. Further, periodontal treatment creates a perceptible colour change in all zones under study, which is not dependent on either the patient’s biotype or initial severity of inflammation. Clinical Significance. Digital spectrophotometric analysis provides a valuable technological enhancement to quantify gingival colour and record changes in gingival colour during the course of periodontal treatment. Regardless of the initial severity of gingival inflammation, a perceptible increase in the L* coordinate (gums become visibly lighter) can be expected after periodontal treatment. Regardless of the initial severity of inflammation, a perceptible increase in the L* coordinate can be expected (gums become visibly lighter) after treatment.
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Barreto, Anna, Jorge M. Martins, Nuno Ferreira, Isabel Brás, and Luisa H. Carvalho. "Valorisation of Forest Waste into Natural Textile Dyes—Case Study of Pine Cones." Forests 16, no. 5 (2025): 769. https://doi.org/10.3390/f16050769.
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The pine cone is an important forest product for the Portuguese economy. However, it is associated with environmental impacts, such as the generation of waste and the increased risk of forest fires. The objective of this research is to valorise waste from the production of Pinus pinaster Aiton in the form of natural dyes. The pine cone extracts were characterised in different alkaline solutions (1%, 5% and 10% NaOH) in order to evaluate the dyeing process on cotton knitwear, using the CIELab coordinates. The dyed samples were also subjected to light and water fastness tests. The extracts showed an increase in solids content with increasing alkalinity and a reduction in antioxidant content. The phenol content increased in the extract with 5% but decreased with the 10% concentration. All the dyes expressed a pink colour but with different shades. About the L* coordinate (luminosity), the colours became lighter as the NaOH increased. In the a* coordinate, all the samples had a reddish colour, and, in the b* coordinate, all the samples had a yellowish colour. About light and water fastness, all the samples lost colour, but in the water test, it was not noticeable.
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H. Horváth, Zsuzsanna. "Analysis of change of the colour parameters of paprika powder with different added oleoresin." Analecta Technica Szegedinensia 7, no. 1-2 (2013): 16–21. http://dx.doi.org/10.14232/analecta.2013.1-2.16-21.
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The instrumental colour measurement isn’t used in course of the making and the qualification of the paprika powder, although the colour is the most important sense property of its. Paprika is also used as a natural food colour. The colour of paprika powder is very important too, because the consumer concludes its colouring power based on its colour. The colouring power is determined by quality and quantity of colouring agent of paprika squarely. The colour of the powder is influenced by its particle size, oil content and moisture content and first of all the colour agent content.We investigated how the colour agent content increasing influences the colour characteristics of paprika powders. The L*, a*, b* colour coordinates defined in the CIELab colour space were applied for the colour characterization. The measurements were carried out using a Minolta CR-300 tristimulus colour analyser.We loosed the colour agent from the paprika powder samples using acetone. The colour agent content of obtained samples was less than 10 ASTA units. After different quantity of oleoresin ( 0.0186 g, 0.0461 g, 0.0626 g, 0.0953 g, 0.3500 g, 0.6399 g) was added to samples of 10 g of powder. The colour characteristics and colour agent content of these samples were determined. The relation between colour agent content and colour coordinates was analysed using regression analysis and the colour differences ΔE*ab were determined between samples with different colour agent content.The results depicted that L* lightness coordinate decreased with increasing colour agent content, the points fitted on a reciprocal function with a significant correlation ( p=0.01). In the case of a* redness coordinate the points fitted on a saturation function (0.01), the redness coordinate didn’t change above 129 ASTA units. The b* yellowness coordinate increased to 97 ASTA units, then decreased, the points fitted on a second degree function with a significant correlation (p=0.01). The function has maximum at 97.17 ASTA units; the maximum value was 25.22 coordinate units. The value of hue angle (hoab) progressively decreased while the colour agent content was added. The C*ab chroma increased to 121 ASTA units, then decreased, the points fitted on a second degree function with a significant correlation (p=0.01). It depicts, that the colour of powder became more red and darker as the colour agent content increased. The colour differences ΔE*abcalculated between samples with different colour agent content were smaller above 130 ASTA units. It shows that the rate of the change of the paprika powders colour was smaller while the colour agent content increased.
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Geelani, Syed Maqbool, Shoukat Ara, Pradeep Kumar Mishra, et al. "Eco-friendly dyeing of wool and pashmina fabric using Quercus robur L. (fruit cups) dye and Salix alba L. (wood extract) mordant." Journal of Applied and Natural Science 7, no. 1 (2015): 138–43. http://dx.doi.org/10.31018/jans.v7i1.577.
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Study was conducted to investigate the dyeing potential of Quercus robur L. (fruit cups) dye and Salix alba L. (wood extract) mordant on wool and pashmina fabrics. The experiment was conducted keeping in view the environmental safety by using unutilized plant materials and excluding the usage of chemical agents. The dyeing was carried out individually including and excluding mordant adopting different mordanting methods. The parameters like percent absorption, colour coordinates, colour strength (K/S), relative colour strength and colour fastness with regard to washing, light and rubbing were investigated. The results revealed higher percent absorption of mordanted samples than unmordanted samples. Colour coordinates (L*a*b*, Chroma, hue and ΔE) of dyed wool and pashmina fabric exhibited satisfactory results. The colour strength (K/S) and relative colour strength of pashmina fabric recorded higher than wool fabric. The fastness properties to washing, light and rubbing showed satisfactory grades including and excluding natural mordant. However, the grades of mordanted samples were found better than unmordanted samples. The dye and mordant in isolation and in combination showed beautiful colours and shades on selected fabrics with satisfactory retention properties, hence can be utilized commercially for coloration of wool and pashmina fabrics.
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Rubiño, M., J. A. García, L. Jiménez del Barco, and J. Romero. "Colour Measurement of Human Teeth and Evaluation of a Colour Guide." Color Research & Application 19, no. 1 (1994): 19–22. http://dx.doi.org/10.1111/j.1520-6378.1994.tb00055.x.
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In the present work the colour coordinates have been obtained in the CIELAB system (L*,a*,b*) for the teeth of 600 individuals. to determine the region of the CIELAB space which contains all the different hues found in human teeth. In addition. one of the colour guides most used in dentistry has been studied to compare the hue range in this guide with the range possible in human teeth. The results show that colour coordinates of human teeth fall within an elliptical contour centered in a yellowish white. The colour guide studied did not cover all the possible values found for teeth chromaticities.
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DZURENDA, LADISLAV. "The effect of UV radiation in Xenotest 450 on the colour of steamed beech wood during the process of simulated ageing." Annals of WULS, Forestry and Wood Technology 106 (January 15, 2019): 114–20. http://dx.doi.org/10.5604/01.3001.0013.7746.
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The effect of UV radiation in Xenotest 450 on the colour of steamed beech wood during the process of simulated ageing .The aim of the paper is to present the changes in colour of steamed beech wood in the pocess of simulated ageing in Xenotest 450. Red-brown colour of beech wood with the coordinates of L* = 62.6 ± 2.8; a* = 10.9 ± 2.3; b* = 17.1 ± 1.3 in the CIE L*a*b* colour space resulted from the mode of colour modification of wood with saturated vapour with the temperature of t = 120 ± 2 oC for τ = 6.5 hours. The surface of samples after drying to the moisture content of w = 12 % and planing was irradiated in Xenotest 450 with xenon gasdischarge tube by UV radiation with the wave length of 340 nm. Accelerated ageing experiment ran in exposure period A1 for seven days. Simulated ageing of thermally treated beech wood showed that due to UV radiation, the wood surface is turning pale and brown. The change in the lightness coordinate by the value of ΔL* = + 6.7 shows the rate of change in the surface lightness and the changes in the values of chromatic coordinates of red colour by the value of Δa* = - 0.1 and yellow colour by Δb* = + 12.3 shows the rate of getting brown. Therefore the hue angle increases from h*ab = 57.5 ° to h°ab = 69.8 °. The value of the total colour difference resulting from the process of ageing is ΔE* = 14.5.
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Zhbanova, Vera L. "Evaluation And Selection Of Colour Spaces For Digital Systems." Volume 28, Number 6, 2020, no. 03-2020 (December 2020): 86–94. http://dx.doi.org/10.33383/2020-024.
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The research examined the changing of colour difference by the control colours depending on the choice of colour space when working with matrix photo detector. The spectral characteristics of photo detectors from different manufacturers noticeably differ from each other and from the addition the difference in colour quality between different digital devices. A software method for studying the colour rendition of the image obtained by digital devices based on the selection of an individual colour space for each matrix photo detector is proposed. To analyze and evaluate the capabilities of the spectral characteristics of matrix photo detectors, the control colour method based on the Mansell Atlas was used. The analysis of the obtained parameters of 14 colours was carried out according to various criteria for seven colour spaces: sRGB, AdobeRGB, DCI-P3 RGB, M1N1P1, PAL / SECAM, Wide Gamut RGB, ProPhoto RGB. Also studied the influence of the choice of colour space on the change in the coordinates of the source 6,500 K. Based on the colour differences of the control colours, it is possible to choose the optimal colour space for working with a specific matrix photo detector. The latter will reduce colour distortion at the initial stage of image registration. The ways for improving the colorimetric method of control colours are proposed as applied to digital devices at the software level.
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Hălălișan, Aureliu-Florin, Florin Dinulică, Dan Marian Gurean, et al. "Wood Colour Variations of Quercus Species in Romania." Forests 14, no. 2 (2023): 230. http://dx.doi.org/10.3390/f14020230.
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Wood colour metrics are increasingly being used in wood technology and ecology studies. Researchers usually determine the colours of the wood after treatment or in different habitats. There is very little research dedicated to the problem of colour variations among one specific species harvested in different forests or regions. The main purpose of the current research is to reveal and estimate the colour variability of oak species. For this study, a total of 89 samples were taken from the heartwood of seven oak species (Quercus robur L., Quercus cerris L., Quercus rubra L., Quercus pedunculiflora K. Koch., Quercus pubescens Willd., Quercus petraea (Matt.) Liebl., and Quercus palustris Muenchh.). The CIELAB system was used for the assessment of the colour differences. To determine the colour groups and variations, K-means clustering was used. The results show that colour variations do exist. According to the cluster analysis, at least five types of oak wood can be distinguished (because in some clusters, very few samples were present) in the investigated forests. The differences are mainly observed in terms of the lightness (L*) and yellowness (b*). Redness is not a feature by which oak wood differs, but the wood can be brighter or more yellow in some of the samples. The density of the Romanian oaks in the sample does not influence the colour coordinates. The only coordinate affected is a*, but with a very small probability.
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Geelani, Syed Maqbool, Shoukat Ara, Naseer A.Mir, et al. "Natural dyeing of fabrics using Quercus robur L. (fruit cups) dye and Punica granatum L. (peel) mordant." Journal of Phytopharmacology 2, no. 6 (2013): 52–58. http://dx.doi.org/10.31254/phyto.2013.2609.
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Investigation was carried out to study the dyeing quality of Quercus robur L. (fruit cups) and Punica granatum L. (peel) mordant for the dyeing of wool and cotton fabrics. The fabrics were dyed both excluding and including the mordant by adopting different mordanting methods. The efficiency of the dye and mordant combinations was evaluated in terms of percent absorption (%), Colour coordinates (CIELAB), Colour strength/ Relative colour strength (K/S) and fastness properties respectively. Absorption of the dye, colour coordinates, colour strength (K/S) by the wool fabric recorded higher values as compared to cotton fabric. The cotton fabric does not showed much affinity for the dye and mordant combinations and appeared with dull and poor colour shades with lower values of absorption, colour strength and retention grades. However, wool fabric showed beautiful and bright colour shades in different mordanting combinations.
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Gedvila, Andrius, and Jonas Sidaravičius. "INVESTIGATION INTO THE ACCURACY OF COLOURS REPRODUCED BY THE RICOH PRINTER / SPAUSDINTUVO „RICOH“ SPALVŲ REPRODUKAVIMO TIKSLUMO TYRIMAS." Mokslas - Lietuvos ateitis 6, no. 4 (2013): 583–87. http://dx.doi.org/10.3846/mla.2012.97.
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The paper investigates the reproduction accuracy of Ricoh Aficio colour 3006 printer. The study has been conducted analyzing four-color (CMYK) gradation curves – the compliance of zonal absorbance with standard references and printing stability of gradation scales. The obtained colours have been measured spectrophotometrically determining the coordinates of colours CIE L*a*b* and differences in colours ΔE. Eight printing regimes and their settings have been examined. It has been found that the printer Ricoh has inaccurately colour grading. However, the quality of colour reproduction is sufficient for printing data not requiring high accuracy of colour reproduction. Colour grading significantly differs from the theoretical approaches, though some regimes (Gamma, Brightness, CMYK simulation) allows achieving theoretical values. Despite the high inaccuracy of gradation, differences in colour are not high enough due to corrections made by software. Santrauka Darbe tirtas spalvinio spausdintuvo ,,Ricoh Aficio 3006“ spalvų atgaminimo tikslumas. Tyrimas atliktas analizuojant keturių spalvų (CMYK) gradacines kreives – zoninių optinių tankių atitiktį etalonui ir gradacinių skalių spausdinimo stabilumą pagal zoninių optinių tankių verčių sklaidą. Spalvų iškraipymas tirtas spektrofotometriniu metodu nustatant spalvų CIE L*a*b* koordinates ir spalvų skirtumus ΔE lyginant su etalonu. Tyrimai atlikti esant 8 spausdinimo režimams ir keičiant tų režimų nustatymus. Nustatyta, kad spausdintuvas „Ricoh“ spalvas atkuria netiksliai, tačiau spalvų atgaminimo kokybė patenkinama, esant spalvų reprodukavimo aukštos kokybės nereikalaujantiems darbams. Spalvų gradacijos gerokai skiriasi nuo teorinių, bet kai kurie režimai („Gamma“, „Brightness“, „CMYK Simulation“) leidžia atspaudų gradacijas priartinti prie teorinių. Nepaisant didelių gradacinių skirtumų visų spalvų skirtumas lyginant su teoriniu nėra didelis galimai dėl spausdintuvo programinio spalvų koregavimo.
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Shualdi, Wedianti, Nik Mohd Azmi, Nurul Huda Yusoff, Nor Adhila Muhammad, and Khairuldin Mohd Isha. "Thermally Stable Encapsulation Material Based on Green and Red Lanthanide Phosphor for White Light Emitting Diodes." Applied Mechanics and Materials 815 (November 2015): 182–87. http://dx.doi.org/10.4028/www.scientific.net/amm.815.182.
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This study reported thermal stability of hybrid sol-gel encapsulation materials doped with lanthanides complexes for generating white light. Red and green lanthanide phosphor, Eu (tta)3phen and Tb (4DBBA)3TPPO were incorporated into VTES:TEOS hybrid sol-gel and dispensed into 360 nm to 390 nm UV LED packages. Thermal properties of developed encapsulation material were analysed by TGA. A thermal aging test up to 96 hours was done to check the stability of developed encapsulation material towards UV LED junction temperature of 120°C and the luminescence properties changes was observed using photoluminescence measurement. To check the encapsulation material stability on forward voltage, the operation voltage has been increased from 3.0V to 4.0V. The photometric measurement were recorded using integrating sphere for the properties of Colour Rendering Index (CRI), colour temperature and Commission Internationale de L’Eclairge (CIE) colour coordinates. Based on the results, developed encapsulation material produced white colour with CIE colour coordinate of (0.32, 0.35), CRI up to 75 and colour temperature around 6000K.
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Murashеv, Sergey V., Elena A. Gorlach, Alexander N. Chertov, Elena V. Gorbunova, and Elena I. Kiprushkina. "DEVELOPMENT OF A COLOURIMETRIC METHOD FOR QUALITY CONTROL OF SAUSAGE PRODUCTS PRODUCED USING CHITINOUS FOOD ADDITIVES." Progress on Chemistry and Application of Chitin and its Derivatives XXV (September 30, 2020): 151–63. http://dx.doi.org/10.15259/pcacd.25.012.
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A crucial technological task that must be solved in the production of sausage products is to stabilize the product’s red colour. In this paper, we propose a scheme to determine the most significant parameters of the quality of dry-cured sausages by their colour characteristics. For this purpose, colour digital images were obtained, which were further processed using two classical colour representation systems: RGB and xyY. We monitored changes in pH and the ratio of water to dry matter in meat products. These crucial sausage properties were changed by introducing chitin-containing supplements into their recipes, which allowed us to solve two tasks simultaneously. The first comprises, as already mentioned, changing the properties of sausages to obtain correlations with colour characteristics. The second is to enrich meat products with chitin complex for preventive purposes to improve people’s nutrition. The construction of correlation dependencies using each coordinate separately in two colour systems showed that each system (RGB and xyY) has one colour channel with a maximum correlation coefficient. This is due to the colour features of sausages, which can be represented to the greatest extent with the help of only one colour coordinate in the considered colour representation systems (RGB and xyY). Using these colour coordinates will allow one to achieve maximum measurement accuracy. Thus, two tasks are being solved: the enrichment of food with dietary supplement and the development of a method to control their content.
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Gómez-Polo, Cristina, Miguel Gómez-Polo, Norberto Quispe Quispe López, Maria Portillo Portillo Muñoz, and Javier Montero. "3D Master Toothguide Is Adequate to Subjective Shade Selection?" Medicina 58, no. 3 (2022): 457. http://dx.doi.org/10.3390/medicina58030457.
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Background and Objectives: To study the validity and the degree of representability of the toothguide 3D Master, with 26 physically shade tabs, on the natural tooth colour on a sample of the Spanish population. Materials and Methods: Natural tooth colour was measured in a sample of 1361 Spanish participants of both genders distributed within an age range of 18 and 89 years of age. The colour coordinates were calculated and the frequency of the 26 physically shade tabs of the toothguide as well as the “intermediate shades” (without physical representation in toothguide) through the Easyshade Compact (Vita-Zahnfabrik) spectrophotometer using the 3D Master System nomenclature. The colour differences between the “intermediate shades” were calculated using the Euclidean formula (ΔEab*). The program used for the present descriptive statistical analysis of the results was SAS 9.1.3. Results: A total of 49 “intermediate shades” were registered in 816 participants (60%). The colour coordinates of the 49 ‘intermediate shades’ cover colour coordinates ranging from 0M1.5 (L* 100.0, C* 7.70, h* 112.2) to 5M2.5 (L* 56.8, C* 35.8, h* 78.5). Not all possible 3D Master System’s “intermediate shades” were registered in the population studied. 82.4% of the colour differences among the “intermediate shades” were clinically unacceptable (ΔEab* ≥ 5.5 units). Conclusion: Only 40% of the population studied presented a natural tooth colour belonging to the 3D Master Toothguide´s physical shade tabs.
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Ukrainskiy, Pavel, Fedor Lisetskii, and Arseniy Poletaev. "Differentiating Soils from Arable and Fallow Land Using Spectrometry." Soil Systems 5, no. 3 (2021): 54. http://dx.doi.org/10.3390/soilsystems5030054.
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In this study, we analyse soil system responses—in particular, the colours of soils resulting from different types of land use (arable land and residential areas) caused by the construction of an ancient boundary rampart near a multilayer monument dating from between prehistory and the Middle Ages within the boundaries of the Bosporus Kingdom (Eastern Crimea)—in an area of modern and ancient (4th–2nd centuries BC) land use (Northwestern Crimea). These differences are of interest because they offer the chance to decipher different types of ancient land use and systems of land surveying, incorporating data from colour aerial photographs obtained with the help of unmanned aerial vehicles. Soil samples displaying different types of anthropogenic transformation were taken from the ancient boundary ramparts and adjacent land. The soil colour coordinates in the CIE L*a*b system were measured with the help of an AvaSpec-2048 spectrometer. Differences in colour coordinates were analysed using analysis of variance (NPMANOVA) based on the permutation test, the Kruskal–Wallis test, and the Mann–Whitney test, corrected according to multiple comparisons carried out as per the Bonferroni method. The results of this statistical analysis show that there are statistically significant differences in soil colour coordinates between samples collected on the ramparts and under various other types of land use. These differences are more pronounced in the samples characterised by the agrogenic transformation of soil. This makes it possible to use remote sensing data to detect traces of ancient boundary ramparts, even if the ramparts are partially destroyed by ploughing.
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Jan, Latal, Hanulak Patrik, Kolar Jakub, Wilcek Zdenek, Stratil Tomas, and Sarlej Filip. "Measurement of colour coordinates of LEDs used in the automotive exterior lighting." International Journal of Electrical and Computer Engineering (IJECE) 11, no. 3 (2021): 2711–24. https://doi.org/10.11591/ijece.v11i3.pp2711-2724.
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Article deals with dichromatic white light-emitting diode (LED’s) color coordinates used in automotive exterior lighting. This article also describes basic white automotive LED functionality and basic physical processes that create white light of these LEDs. It focuses on measuring color coordinates of white automotive LEDs with different temperature of LED and how the LED’s color depends on LED’s temperature. The article is comparing very important datasheet information of LED producers and values measured in the laboratory at university. The article contains statistical results of measurements and graphical representation of measured values and declared color bins which are very important for producers of headlamps for automotive companies.
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Lemr, Karel, and Milan Kotouček. "Evaluation of colour changes of screened acid-base indicators." Collection of Czechoslovak Chemical Communications 54, no. 2 (1989): 346–60. http://dx.doi.org/10.1135/cccc19890346.
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Based on computer-assisted calculations, six screened indicators were prepared and used for visual titration end point indication. Three of them were evaluated in terms of objective colour characteristics. Their colour changes were characterized in the CIE-xy (1931) international colorimetric system, by the Helmholtz coordinates, complementary Qx, Qy coordinates, perceptibility and course of the ΔJ/ΔpH = f(pH) function. In addition, new indices were introduced, viz. partial quality indices IE, Ip and Im, related with the colour difference between the two indicator species (IE), their colour purity (Ip) and the experimenter's ability to remember the colour in the titration end point (Im). Summed up, the three indices constitute the total quality index of the chemical indicator It. These indices were employed for comparing the single and the corresponding screened indicators.
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Chahal, T. S., Varinder Singh, PPS Gill, SK Jawandha, and Vikramjit Singh. "Fruit colour progression in grapefruit with relation to carotenoid and Brix-acid ratio." Indian Journal of Horticulture 80, no. 2 (2023): 184–89. http://dx.doi.org/10.58993/ijh/2023.80.2.9.
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In citrus, fruit colouration is considered one of the criteria to assess the optimum harvest maturity. The present study the fruit colour variations, β-carotene and its relation to soluble Brix/acid ratio (B/A ratio) during development in four grapefruit varieties viz. Marsh Seedless, Flame, Rio Red and Redblush were investigated. Among different grapefruit varieties, the highest peel colour coordinate a* value and β-carotene content were recorded in cv. Flame at 270 days after full bloom (DAFS). The peel β-carotene concentration varied from 3.61 to 61.42 μg.g-1 during fruit development. L*coordinate showed a declining pattern in the pulp, while it increased in peel till 270 DAFS. Likewise, b* values also increased in both peel and pulp. Chroma (C*) and B/A ratio values of fruit increased with maturity, while the hue angle (h°) decreased. L*a*b*colour coordinates showed a strong correlation with B/A ratio compared to β-carotene content. At the final fruit harvest, the higher value for L* coordinate in peel and pulp was noted in ‘Redblush’ and ‘Marsh Seedless’. In contrast, the highest b* coordinate was observed in the peel and pulp of the Marsh Seedless variety. Overall, a* coordinate was observed to be the most reliable colour parameter to determine the maturity index in the studied varieties of grapefruit.
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Chełpiński, Piotr, Ireneusz Ochmian, and Paweł Forczmański. "Sweet Cherry Skin Colour Measurement as an Non-Destructive Indicator of Fruit Maturity." Acta Universitatis Cibiniensis. Series E: Food Technology 23, no. 2 (2019): 157–66. http://dx.doi.org/10.2478/aucft-2019-0019.
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Abstract Colour measurement is one of the methods used to evaluate food quality. Aim of completed research was the evaluation of a fast and non-destructive method which consisted of assessing colour changes. It was used to determine the ripeness of cherries during their harvest. Additionally, the most significant parameter determining fruit ripeness was identified. Colour measurements of the Burlat cherry on the PHL A rootstocks were supposed to provide standards for practical evaluation of fruit ripeness of this species at an orchard. During the research, the measurements concerned the internal quality of the cherry fruit (firmness, extract content) and the force required to tear off the stem, depending on the size of the fruit. The extract appeared to be the most important indicator to be used for the determination of an optimum harvesting period. It was most prominently correlated with the cherry’s colour. Changes in the skin colour were the most reflected by the value of the parameter CIE a*. The coordinates CIE L* and b* are also important for the determination of fruit quality. Burlat cherries achieve their optimum harvesting ripeness if the coordinate a* is within the range 30.0 to 0.0, the coordinate b* within 10.0 to 0.0 and the coordinate L* within 30.0 to 20.0, which corresponds to the extract value of 12-20%.
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Hernández, Alejandra Díaz, Ana María Martín Casado, Miguel Gómez-Polo, Alicia Celemín Viñuela, and Cristina Gómez-Polo. "Degree of Standardisation in Ceramic Gingival Systems." Materials 16, no. 20 (2023): 6710. http://dx.doi.org/10.3390/ma16206710.
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No gingival shade guide exists that can be used as a ‘gold standard’ in gingival shade selection. This research, therefore, aimed to determine whether comparable results in subjective gingival shade selection can be achieved using basic gingival colours produced by distinct manufacturers. It also aimed to explore how coverage of the colour space is affected by mixing these basic colours to create additional shades. To achieve these objectives, the basic gingival colours of three ceramic systems (Heraceram, Kulzer, Madrid, Spain; Vita VM9, Vita Zahnfabrik, Bad Säckingen, Germany; IPS Style, Ivoclar, Schaan, Liechtenstein) were analysed. The colour systems were expanded by creating porcelain gingival samples, whose colours were obtained by mixing the basic colours, altering each mixture by increments of 10%, and respecting the numerical order used by manufacturers to identify the colours. The colour coordinates of the basic and additional colours were recorded using spectrophotometry, and the intra- and inter-system colour differences were calculated using the Euclidean (ΔEab) and CIEDE2000 (ΔE00) formulae. None of the basic colours in the three systems, despite their similar nomenclature, were found to be interchangeable (the colour differences exceeded the gingival acceptability threshold: ΔE00 2.9 units). The expanded gingival colour systems, with mixtures altered by 10% increments, notably increased the gingival colour space covered by the original systems. The authors concluded that there are clear differences between the basic gingival colours produced by distinct manufacturers using the same nomenclature. Ceramic samples produced by mixing basic gingival colours are a resource with the potential to improve subjective gingival shade matching.
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Mikalainis, Povilas, Jonas Sidaravičius, and Vytautas Turla. "THE INFLUENCE OF FORMULATING A DAMPING SOLUTION ON DOT GAIN." Mokslas - Lietuvos ateitis 2, no. 4 (2010): 18–23. http://dx.doi.org/10.3846/mla.2010.061.
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Difference in dot gain using various additives to the damping solution was investigated on two offset web presses. Dot gain was measured using a densitometer and calculated considering CIE L*a*b* coordinates. It was found that while using a non alcohol additive instead of the alcohol one, dot gain became smaller and printing stability was lower. Changes in dot gain depend on the ink that may vary in colours. The influence of changes in dot gain on the colour was determined. Besides, it was found that differences in colour were unacceptable in many cases.
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Hasegawa, T., and R. Iiyama. "Difference in Perceived Colour between Painted Chips and CRT Images." Perception 26, no. 1_suppl (1997): 171. http://dx.doi.org/10.1068/v970339.
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The inducing effect of blue in colour assimilation on a CRT screen is so strong that pale blue apparently veils the stimulus pattern (Miyamoto and Hasegawa, 1996 Perception25 Supplement, 105). A similar tendency can be observed on painted paper, but this effect is not so marked. This led us to try colour matching between coloured papers and colours reproduced on a CRT screen. In both conditions the shapes (square) and the sizes (35 cm × 35 cm) were the same. They were displayed in the centre of a 155 cm × 155 cm gray (Munsell value 5, 22 cd cm−2) square with 10 cm wide white fringe (74 cd cm−2). The task was to adjust the colour on the CRT screen to match the coloured chip which was inside an illuminated box at a viewing distance of 180 cm in a dark room. Twenty-four colours were tested. Matched blues and other blue hues were slightly more saturated than object colours, but differences in chromaticity coordinates ( u‘ v’) were not statistically significant. This result is opposite to the prediction because it suggests a less bluish impression in the film-colour mode. By contrast, luminance in matched blues was lower than that of the object. This means that the brightness effect increased. An additional experiment in which the stimulus size was larger and the illuminating condition was changed to a light room produced the following results: (i) no meaningful difference in chromaticity coordinates could be seen; and (ii) the luminance of matched colours increased with size and in the lighter viewing condition. These facts show that the bluish colours on the CRT screen do not change their perceived chromaticity or spread spatially. The only difference was the subjective brightness increase in the condition when the room was dark. The strong effect of the blues in assimilation on the screen, therefore, does not depend on the colour identification process itself, but on the combined effect of luminosity and visual frequency response.
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Brown, N., M. R. Jackson, and R. M. Parkin. "Automatic gravure print feature determination at production speeds." Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 217, no. 8 (2003): 1101–10. http://dx.doi.org/10.1177/095440540321700807.
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This paper describes the development of a non-contact system for measuring the colour of printed material at web speeds, in addition to gravure-printed dot feature recognition. The system proposed uses a non-contact spectrophotometer based on a holographic grating, in conjunction with a conventional monochrome area scan camera, from which colour spectral data are extracted, while a xenon flash is used to illuminate colour samples. Dot features are captured by a magnification lens, in conjunction with a progressive scan camera. Software and hardware details of the system are given, together with the underlying mathematics for colour space conversion and measurement. Conversion equations from X, Y, Z chromaticity coordinates to the RGB system are presented, and also equations to convert from the L* a* b* colour space to X, Y, Z chromaticity coordinates. Experimental results are presented whereby the non-contact spectral system is shown to perform to a colour tolerance exceeding that of conventional colour video systems, and where performance of the dot feature system is comparable with traditional static examination methods using a microscope.
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Dzurenda, Ladislav. "Mode for hot air drying of alder blanks that retain the colour acquired during the steaming process." Annals of WULS, Forestry and Wood Technology 114 (June 28, 2021): 86–91. http://dx.doi.org/10.5604/01.3001.0015.2379.
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Mode for hot air drying of alder blanks that retain the colour acquired during the steaming process. The paper presents a hot-air mode for drying steamed alder in the form of blanks with dimensions: 38x100x800 mm from the initial moisture content W1 ≈ 50 % to the final moisture content W2 = 10%, while maintaining the colour of wood obtained in the process of steaming with saturated water steam. The drying process is divided into two parts: (I) evaporation of free water from wet wood at drying medium temperatures td = 35 - 40 °C and relative air humidity φ = 70 – 60%, when there are no chemical changes in the lignin-saccharide complex of alder wood manifested by a change in colour; (II) evaporation of bound water from alder wood below the hygroscopicity limit is performed at temperatures td = 60 - 80 °C. The color coordinates of steamed alder wood after drying by a given mode in the CIE L* a* b* colour space are: L* = 62.5 ± 1.7; a* = 13.1 ± 0.8; b* = 18.5 ± 0.9. Total colour difference ∆E = 1.6. According to the categorization of wood color changes in thermal processes of wood , this change belongs to small (insignificant) color changes.
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Kirk, Richard A. "Chromaticity coordinates for graphic arts based on CIE 2006 LMS with even spacing of Munsell colours." Color and Imaging Conference 2019, no. 1 (2019): 215–19. http://dx.doi.org/10.2352/issn.2169-2629.2019.27.38.
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We construct redness-greenness (r,g) coordinates to fit the spectral locus into a triangle in the normalised CIE 2006 LMS plane. The reflection spectra for the Munsell patches for blackbody illuminants from 5000 to 6500 K appear as near circles in this space, suggesting that equal steps in (r,g) space may correspond to equal perceived colour contrasts within the gamut of reflective colours. We fit a matrix to convert from XYZ to LMS for reflective colours.
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Zhu, Meilin, and Ying Guo. "New Insights into the Coloration Mechanism in Spessartines and the Impact of Munsell Neutral Grey Backgrounds." Crystals 13, no. 11 (2023): 1529. http://dx.doi.org/10.3390/cryst13111529.
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In this study about spessartines,13 spessartine samples with proper conditions are used for FTIR spectrum and UV-Vis spectrum tests to find the gemological characteristics and coloration mechanism. In the UV-Vis spectrum, spessartines’ special color has a relationship with the absorption bands at about 460 nm and 480 nm. Based on the CIE 1976 L*a*b* colour system, we come to the conclusion that both color coordinates a* and b* control the value of chroma C*, and color coordinate b* mostly controls the hue angle h°. We also explore how the different chromogenic ions FeOtot and MnO and their ratio FeOtot/MnO influence spessartines’ color, finding that the color of spessartine samples is influenced by both Mn and Fe. By analyzing the FTIR spectrum, we discovered that as the content of Mn decreases, and the A, C and D peaks move to the position of a longer wave, the color of spessartine samples also changes significantly. By using the standard light source D65, we find that N9.5 Neutral Grey Background is the best background to grade the color of spessartines.
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F. Che Rahim, A., M. R. Ahmad, K. Ismail, and M. I. Ab Kadir. "Natural Dyes from Chlorella Vulgaris sp Extracted via Supercritical Fluid Extraction Dyed on Silk Fabric." International Journal of Engineering & Technology 7, no. 4.14 (2019): 326. http://dx.doi.org/10.14419/ijet.v7i4.14.27666.
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Of late, research on natural dyes is increasing due to its eco-friendly and less hazardous nature towards humankind. This study focuses on the colour coordinates and colour strength of dyes from Chlorella Vulgaris sp extracted via Supercritical Fluid Extraction (SFE). The SFE optimum parameters for yield extracts were obtained through response surface methodology along with central composite design approach. Exhaustion dyeing with meta-chrome method was performed on silk fabrics for 60 minutes at 85oC. The dyed silk fabrics were measured and analysed for their colourimetric and fastness properties in accordance to MS ISO and AATCC standards, respectively. The colour shades on the dyed silk fabrics using alum mordant were light brown while for the iron mordant were dark brown. These shades were confirmed with the colour coordinates, L*a*b*, values of the fabrics. The colour strengths of the fabrics dyed with the iron mordant at 2% and 5% dyes were the highest in comparisons with other dyed fabrics. Overall, the colourfastness of the fabrics to washing were quite low but with very good colour staining ratings and fastness to perspiration, rubbing and light.
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Kúdela, Jozef, Ivan Kubovský, and Michal Andrejko. "Discolouration and Chemical Changes of Beech Wood After CO2 Laser Engraving." Forests 15, no. 12 (2024): 2211. https://doi.org/10.3390/f15122211.
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This study evaluated the influence of infrared laser radiation produced by a CO2 laser, performing under different engraving parameters, on the colour changes and chemical composition of a beech wood surface. The results showed that the lightness clearly decreased with increasing laser power and density. At the highest laser power and the highest raster density, the ΔL* value was 51.3. The values of coordinates a* and b* moderately increased up to a raster density of 5 mm−1; then, with a subsequent raster density increase, the values of these coordinates decreased again. However, the coordinate values were positive in all cases. Even the lowest laser power and raster density resulted in conspicuous discolouration or even a completely new colour compared to the original (ΔE = 10) of the beech wood surface. Further increases in the laser power and raster density resulted in progressively pronounced colour differences and a darker brown colour of the surface. The ATR-FTIR chemical analysis of the beech wood surface revealed that discolouration was mainly caused by heat-induced processes associated with the degradation of carbonyl groups (C=O) in lignin and hemicelluloses. The splitting of C=O bonds induced changes in the content of chromophores responsible for the natural wood colour and for the engraving-related discolouration. The study demonstrates that the amount of energy supplied onto the wood surface by a laser beam using diverse combinations of radiation parameters can be represented by a single variable: the total irradiation dose. The functional relation detected between this variable and the colour differences may serve as a basis for using a controlled laser beam for targeted wood surface discolouration to improve the quality of patterns transferred onto a wood surface. Knowledge of this relation will enable the targeted setting of the laser parameters during engraving so that the laser beam can be used as a tool for transferring high-quality patterns onto wood surfaces.
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Yendrikhovskij, S. N., F. J. J. Blommaert, and H. de Ridder. "Memory Representation of Object Colours." Perception 25, no. 1_suppl (1996): 185. http://dx.doi.org/10.1068/v96l1008.
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Memory colours, ie colours recalled in association with familiar objects, impose a powerful constraint on colour appraisal of images of natural scenes. The purpose of this study is to specify the memory representation of one particular object colour. To this end, the colour of a banana was manipulated by varying hue-angle and saturation in the CIELUV colour space. Subjects' task was to rate the similarity in colour of the resulting banana samples displayed on the screen to the typical ripe banana stored in their mind. In order to examine the dependence of memory colour on texture information and context, three ways of presentation were used: original (banana among other fruit), isolated (the same banana against a homogenous gray background), and contour (silhouette of the banana with its average colour against the gray background). The relationships between the similarity judgments and chromaticity coordinates of the manipulated banana-represented points in the CIELUV colour space is described by a bivariate normal distribution with four parameters: two means and two variances of the Gaussians on the hue and saturation dimensions. For all three types of presentation, the variance of hue is significantly smaller than the variance of saturation; this suggests that memory description of hue is more precise than that of saturation. The data show systematic differences in the hue of memory colour between the original, isolated, and contour presentations of the banana. A model describing the hue shift in terms of illuminant and surface information content in the images is discussed.
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GODOVČIN, PETER, JOZEF MARTINKA, PETER RANTUCH, et al. "IMPACT OF TEMPERATURE AND ULTRAVIOLET RADIATION ON CHANGES OF COLOUR OF FIR AND SPRUCE WOOD." WOOD RESEARCH 67(6) 2022 67, no. 6 (2022): 894–907. http://dx.doi.org/10.37763/wr.1336-4561/67.6.894907.
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This study deals with the investigation of impact of temperature and ultraviolet (UV) radiation on spruce wood (Picea abies(L.) H. Karst.) and fir wood (Abies albaMill.) colour changes. Samples of investigated woods species were loaded by temperatures of 110, 130, and 150°C and UV radiation (with 253.7 nm wavelength and 40 W m-2intensity) during 72, 168, 336 and 672 hours. Colour changes were evaluated in the CIE Lab colour space. Theneural network for prediction of both colour coordinates and total colour difference of spruce and fir wood was trained by data regarding exposure conditions (temperature, UV radiation and time) and by obtained results. Coefficient of determination (R2) of the neural network was above 0.99 for training, validation and testing. Average colour coordinates (±standard deviation) of the spruce and fir wood before exposure were L* = 80.08 ± 3.70,a* = 7.55 ± 2.13, b* = 21.56 ± 1.79, L* = 80.46 ± 1.91, a* = 6.84 ± 0.97, and b* = 18.90 ± 1.26, resp. Total colour differences after thermal loading were in the interval from ΔEab* = 3.76 ± 1.95 (spruce wood at 110°C) to ΔEab* = 45.37±1.46 (fir wood at 150°C). Total colour differences of both wood species exposed by UV radiation were approximately in intervals from ΔEab* = 12 to 13 (after 72 h) up to ΔEab* = 16 to 20 (after 168 to 672 h). Obtained results proven that both temperature and UV radiation have significant impact on the colour changes of the investigated woods.
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Bartkiene, Elena, Vytaute Starkute, Ieva Jomantaite, et al. "Multifunctional Nutraceutical Composition Based on Fermented Spirulina, Apple Cider Vinegar, Jerusalem Artichoke, and Bovine Colostrum." Foods 12, no. 8 (2023): 1690. http://dx.doi.org/10.3390/foods12081690.
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The main purpose of this experiment was to develop a multifunctional nutraceutical composition based on ingredients of different origins (Spirulina powder (SP), bovine colostrum (BC), Jerusalem artichoke powder (JAP), and apple cider vinegar (ACV)) which possess different health benefits through their different mechanisms of action. In order to improve the functional properties of Spirulina and bovine colostrum, fermentation with the Pediococcus acidilactici No. 29 and Lacticaseibacillus paracasei LUHS244 strains, respectively, was carried out. These LAB strains were chosen due to their good antimicrobial properties. The following parameters were analysed: for Spirulina (non-treated and fermented)—pH, colour coordinates, fatty acid profile, and contents of L-glutamic and GABA acids; for bovine colostrum (non-treated and fermented)—pH, colour coordinates, dry matter, and microbiological parameters (total LAB, total bacteria, total enterobacteria, Escherichia coli, and mould/yeast counts); for the produced nutraceuticals—hardness, colour coordinates, and overall acceptability. It was established that fermentation reduced the pH of the SP and BC and affected their colour coordinates. Fermented SP contained a greater concentration of gamma-aminobutyric and L-glutamic acids (by 5.2 times and 31.4% more, respectively), compared to the non-treated SP and BC. In addition, the presence of gamma-linolenic and omega-3 fatty acids was observed in fermented SP. Fermentation of BC reduces Escherichia coli, total bacteria, total enterobacteria, and total mould/yeast counts in samples. The obtained three-layer nutraceutical (I layer—fermented SP; II—fermented BC and JAP; III—ACV) demonstrated a high overall acceptability. Finally, our finding suggest that the selected nutraceutical combination has immense potential in the production of a multifunctional product with improved functionality and a high acceptability.
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Huriev, Mykola, Ekaterina Hovorova, Stanislav Shirokov, et al. "COOMET.PR-S11 comparison of COLOUR REFLECTED. Final report." Metrologia 60, no. 1A (2023): 02001. http://dx.doi.org/10.1088/0026-1394/60/1a/02001.
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Main text This report describes performing the international supplementary comparisons of the values of colour coordinates and L *, a *, b * of reflecting surfaces transmitted by means of measurement standards - transfer standards from the participants of comparisons to the coordinating laboratory. These comparisons were carried out within the framework of the regional metrological organization (RMO) "Euro-Asian Cooperation of National Metrological Institutions" (COOMET) in accordance with the COOMET 743 / UA / 18 Project. The National Scientific Center "Institute of Metrology" (NSC "IM", Ukraine) acts as the coordinating laboratory for these comparisons. Supplementary comparisons are aimed at determining the degree of equivalence (DoE) for the National Photometric Laboratories participating in these comparisons. The DoE shows the deviation of the color coordinates and L *, a *, b * values of the reflecting surfaces obtained by the Participant from the Reference Values (RV) obtained between the National Photometric Laboratories participating in these comparisons. The comparisons will support the following CMCs from the classification of services in photometry and radiometry: color, reflection, Y, x, y,; color, reflection L *, a *, b *. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/. The final report has been peer-reviewed and approved for publication by the CCPR, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
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Baumann, C. "Colour as Input to Stereopsis." Perception 26, no. 1_suppl (1997): 83. http://dx.doi.org/10.1068/v970048.
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Neural structures carrying information concerning stereopsis belong to the magnocellular sub system of the visual pathway. Regarding the magnocellular system as insensitive to colour, one would expect a high threshold for chromatic stimuli to evoke stereoscopic depth perception. In the present study, a stereogram together with an equiluminant background was generated on a colour monitor. The monitor was calibrated by a tristimulus colorimeter before each experimental session. The chromaticity coordinates of both stereogram and background could be varied in small steps. The author and two naive subjects participated in the experiments. Two patterns of three vertical bars formed the stereogram which was viewed through a stereoscope. With binocular fusion, the spatial arrangement of the bars gave rise to a horizontal, crossed or uncrossed, disparity of 10 min arc for one of the bars. Accordingly, this bar appeared to float either in front of, or behind, the other two, provided the colour difference between the stereo pair and the background was large enough. Under equiluminant conditions, the minimal colour difference necessary to evoke a depth perception exceeded the just noticeable colour difference at the chromaticity coordinates chosen ( x = 0.265; y = 0.499) by a factor of only 3 to 4. In control experiments, the use of an optical system to compensate ocular chromatic aberrations did not measurably alter the results. These findings indicate that colour has an input to stereopsis which is stronger than a purely magnocellular system could provide.
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Macher, H., L. Roy, and T. Landes. "AUTOMATION OF WINDOWS DETECTION FROM GEOMETRIC AND RADIOMETRIC INFORMATION OF POINT CLOUDS IN A SCAN-TO-BIM PROCESS." International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLIII-B2-2021 (June 28, 2021): 193–200. http://dx.doi.org/10.5194/isprs-archives-xliii-b2-2021-193-2021.
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Abstract. The detection of openings based on point clouds is generally based on geometric features namely the X, Y and Z coordinates of points. Existing methods exploit geometric features but ignore most of the time other attributes as colour and intensity. Such information may be however particularly interesting to recognise and segment openings in facades. In this paper, the use of radiometric information, namely colour and intensity, is investigated for the segmentation of windows from façade point clouds. The assumption is made that windows are significantly different in terms of materials and colours to be distinguished from facade walls. The exploitation of colour and intensity are considered separately. A histogram analysis method is proposed for the exploitation of intensity information whereas a region growing method based on colorimetric distances is considered for the exploitation of colours. In order to refine the results, geometric information, and more precisely depth of points with regards to façade walls, are combined to radiometric information. Several combinations of attributes are considered and provide promising results for windows segmentation based on point clouds.
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Horváth, Zs H. "The effect of storage on the colour of paprika powders with added oleoresin." Acta Universitatis Sapientiae, Alimentaria 9, no. 1 (2016): 50–59. http://dx.doi.org/10.1515/ausal-2016-0005.
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Abstract The use of natural food colours is preferred to that of artificial dyestuffs for modern alimentary purposes. Paprika is a spice plant grown and consumed in considerable quantities worldwide and also used as a natural food colour, so the colouring power of powders is very important. The colour of paprika powder is highly relevant too because the consumer concludes its colouring power based on its colour. The colouring power of paprika powders is directly determined by the quality and quantity of the colouring agent of paprika. The paprika oleoresin, that is an oil soluble extract from the fruits of Capsicum Annum Linn or Capsicum Frutescens, is suitable to raise the colour agent content of paprika powders. We investigated how the colour and the characteristics of paprika powder samples with added oleoresin change in the course of storage. The colour agent content of 7 different quality powders was increased with 7-75% using oleoresin. The initial colour agent content of samples changed between 41 and 169 ASTA units. The powders were made from Chinese, Peruvian, and Hungarian paprika. Colour measurements were performed with a HunterLab MiniScan colour-measuring instrument. The CIELab colour system was used for colour characterization. The colour agent content and the colour coordinates of samples were measured throughout 9 months. The decrease of colour agent content varied between 22 and 51 percent, while the average reduction was 33 percent. The quantity of added oleoresin did not influence the colour agent content decrease significantly. The values of colour difference changed between 2 and 4.5 units. The initial paprika powder influenced the variation significantly, but the quantity of added oleoresin did not have a significant effect.
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Slabejová, Gabriela, and MÁRIA ŠMIDRIAKOVÁ. "Colour stability of surface finishes on thermally modified beech wood." Annals of WULS, Forestry and Wood Technology 114 (June 28, 2021): 116–24. http://dx.doi.org/10.5604/01.3001.0015.2391.
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Colour stability of surface finishes on thermally modified beech wood. The paper deals with the influence of the type of transparent surface finish on the change of colour of the surfaces of native beech wood and thermally modified wood. At the same time, the colour stability of three surface finishes on the surfaces of native and thermally modified beech wood was monitored. Beech wood was thermally modified at temperature of 125 °C for 6 hours. The thermal treatment was performed in a pressure autoclave APDZ 240, by the company Sundermann s.r.o in Banská Štiavnica. Three various types of surface finishes (synthetic, wax-oil, water-based) were applied onto the wood surfaces. The colour of the surfaces of native wood and thermally modified wood was measured in the system CIELab before and after surface finishing; the coordinates L*, a*, b*, C*ab and h*ab were measured. From the coordinates measured before and after surface finishing, the differences were calculated and then the colour difference ∆E* was calculated. Subsequently, the test specimens with the surface finishes were exposed to natural sunlight, behind glass in the interior for 60 days. The surface colour was measured at specified time of the exposure (10, 20, 30, 60 days). The results showed that the colour of the wood surfaces changed after application of the individual surface finishes; and the colour difference reached a change visible with a medium quality filter up to a high colour difference. The wax-oil surface finish caused a high colour difference on native wood and on thermally modified wood as well. On native beech wood, the lowest colour difference after exposure to sunlight was noticeable on the synthetic surface finish. On the surface of wood thermally modified, after exposure to sunlight, the lowest colour difference was noticeable on the surface with no surface finish.
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Indow, T. "Chromatic Response Curves of Surface Colours." Perception 26, no. 1_suppl (1997): 184. http://dx.doi.org/10.1068/v970054.
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Basic data in colour vision such as chromatic response curves were obtained with aperture colours. It is not possible to apply the cancellation technique to define redness or yellowness components etc in a surface colour. A method was developed to obtain such information (Indow, 1987 Die Farbe34 253 – 260), which was based on the expanded form of multidimensional scaling. The results by an improved method are presented. First, it is shown how multiattribute perceptual differences between two Munsell colours, P j, P k, are predicted by distances ^ djk in the current Munsell solid. Colour differences djk are defined by matching with lightness differences in Munsell gray scale and root-mean-squares of ( djk - ^ djk) is 0.2∼0.3 in the unit of Munsell Chroma C. Second, principal hue vectors falpha, alpha= R, Y, G, B, or P in addition, are defined in the current Munsell solid. As shown before, fB is shifted from 5 R in the direction of 5 P, irrespective of whether P is included or not. Overall root-mean-squares of (scaled values of principal hue a in a colour j-coordinates of P j on falpha) is about 0.6 in the unit of C. On the basis of these findings, it becomes possible to define principal hue components for any Munsell colours and hence chromatic response curves are obtained as a function of H, V, and C.
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Aarthi, R., Zadda Kavitha, M. Shanthi, C. Vijayaraghavan, G. Srinivasan, and M. L. Mini. "Enhancing the Trapping of Melon Fruit Fly, Zeugodacus cucurbitae Coquilette through Synergizing the Odour and Visual Cues." Journal of Advances in Biology & Biotechnology 28, no. 1 (2025): 333–45. https://doi.org/10.9734/jabb/2025/v28i11887.
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The melon fruit fly (Zeugodacus cucurbitae Coquillett) poses a significant threat to cucurbit crops with substantial yield losses and challenging sustainable vegetable production. This study systematically investigated efficient color-based visual cues for attracting melon flies and explored the synergistic effects of these visual cues in conjunction with odour cues. This study was conducted in Agricultural College and Research Institute, TNAU, Madurai during 2024. Our studies included investigations on preferred colour by melon fly through olfactometer & insect cage bioassays in no choice & multiple choice conditions. The additive effect of the preferred colour when combined with the fruit fly attractive odour cue was investigated under field conditions. For both male and female melon fruit flies, yellow colour (RBG coordinates - 255:255:0) consistently emerged as the most efficient visual cue followed by white (255:255:255) and red (255:0:0). Field trials also confirmed the attractiveness of yellow colour as it outperformed other colours. The visual cue, yellow colour and odour cue (synthetic blend of four fruit fly EAG active synthetic compounds in a known ratio) were combined and found to be synergistic as this fusing captured significantly more flies than the either cues alone. These results highlighted the yellow colour as the most attractive visual cue for melon flies and combining effective of visual cues with established odour attractant to greatly enhance the trapping efficiency. This integrated approach offers a promising strategy for the management of melon fly and reduction of reliance on chemical pesticides contributing to more sustainable pest control in cucurbit production. The findings have significant implications for pest management strategies, especially in regions facing melon fly infestations that threaten crop yields and export potential.
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Li, Qizheng, Feiyan Zhang, Xiaoke Jin, and Chengyan Zhu. "Optimal yarn colour combination for full-colour fabric design and mixed-colour chromaticity coordinates based on CIE chromaticity diagram analysis." Coloration Technology 130, no. 6 (2014): 437–44. http://dx.doi.org/10.1111/cote.12117.
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TOPRAK, TUBA, MINE AKGUN, and PERVIN ANIS. "Effects of environmentally friendly degumming methods on some surface properties, physical performances and dyeing behaviour of silk fabrics." Industria Textila 71, no. 04 (2020): 380–87. http://dx.doi.org/10.35530/it.071.04.1675.
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In this paper, the effect of degumming processes on the physical performance, surface properties and colour coordinates of silk fabrics at high temperature and enzymatically, which was developed as an alternative to conventional method, has been investigated. Degummed silk fabrics were compared in terms of weight loss, bending length, tear and breaking strength, surface roughness and friction coefficient. After these tests, acid dyeing was performed to observe different degumming methods effect on dyeing behaviour of degummed silk fabric. The colour coordinates were evaluated by L*, a*, b*, C*, h0, K/S, and ∆E* values. The results revealed that despite insignificant differences between conventional and alternative methods in terms of physical performance and surface properties, the conventional method gave slightly better results than the others. There were no significant differences in colour depth between the two processes. These reasons showed that the alternative method could be used instead of the traditional method and a more sustainable process has been designed
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Eyarkai Nambi, V., K. Thangavel, S. Shahir, and V. Geetha. "Evaluation of colour behavior during ripening of Banganapalli mango using CIE-Lab and RGB colour coordinates." Journal of Applied Horticulture 17, no. 03 (2015): 205–9. http://dx.doi.org/10.37855/jah.2015.v17i03.38.
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Silva, Filipa Vinagre Marques, Riccardo Borgo, Andrea Guanziroli, Jorge M. Ricardo-da-Silva, Mafalda Aguiar-Macedo, and Luis M. Redondo. "Pilot Scale Continuous Pulsed Electric Fields Treatments for Vinification and Stabilization of Arinto and Moscatel Graúdo (Vitis vinifera L.) White Grape Varieties: Effects on Sensory and Physico-Chemical Quality of Wines." Beverages 10, no. 1 (2024): 6. http://dx.doi.org/10.3390/beverages10010006.
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Pulsed electric field (PEF) processing of white grapes (Arinto, Moscatel Graúdo also known as Moscatel de Setúbal) before pressing for must extraction (1.2 and 1.6 kV/cm) and before bottling for finished wine physical stabilization (10 kV/cm) was implemented in a pilot-scale winery to produce about 540 L of wine for each variety. PEF was applied at these two different stages of wine production, and its effects on the sensory and physico-chemical quality of the wines were investigated. The sensory triangle tests revealed no significant change in both wine varieties’ colour, odour, and taste with PEF extraction and PEF stabilization treatments. However, for colour coordinates assessed with a spectrophotometer, a significant increase in CIE b* colour coordinate was registered for PEF-extracted Arinto and Moscatel wine samples, showing a development of a more intense yellow colour. Concerning physico-chemical quality parameters, the PEF extraction increased both wine varieties’ turbidity and pH, although total acidity was not affected. The total phenols also increased in Arinto with extraction. The second PEF treatment applied for wine stabilization did not affect any of the quality parameters, except total phenols, which decreased in Moscatel wine. The results encourage the application of PEF in the wineries at different stages of vinification of white wine grape varieties.
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Marqués-Mateu, Á., M. Balaguer-Puig, H. Moreno-Ramón, and S. Ibáñez-Asensio. "A laboratory procedure for measuring and georeferencing soil colour." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-7/W3 (April 28, 2015): 57–64. http://dx.doi.org/10.5194/isprsarchives-xl-7-w3-57-2015.
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Remote sensing and geospatial applications very often require ground truth data to assess outcomes from spatial analyses or environmental models. Those data sets, however, may be difficult to collect in proper format or may even be unavailable. In the particular case of soil colour the collection of reliable ground data can be cumbersome due to measuring methods, colour communication issues, and other practical factors which lead to a lack of standard procedure for soil colour measurement and georeferencing. In this paper we present a laboratory procedure that provides colour coordinates of georeferenced soil samples which become useful in later processing stages of soil mapping and classification from digital images. The procedure requires a laboratory setup consisting of a light booth and a trichromatic colorimeter, together with a computer program that performs colour measurement, storage, and colour space transformation tasks. Measurement tasks are automated by means of specific data logging routines which allow storing recorded colour data in a spatial format. A key feature of the system is the ability of transforming between physically-based colour spaces and the Munsell system which is still the standard in soil science. The working scheme pursues the automation of routine tasks whenever possible and the avoidance of input mistakes by means of a convenient layout of the user interface. The program can readily manage colour and coordinate data sets which eventually allow creating spatial data sets. All the tasks regarding data joining between colorimeter measurements and samples locations are executed by the software in the background, allowing users to concentrate on samples processing. As a result, we obtained a robust and fully functional computer-based procedure which has proven a very useful tool for sample classification or cataloging purposes as well as for integrating soil colour data with other remote sensed and spatial data sets.
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Andres, Julien, and Anne-Sophie Chauvin. "Colorimetry of Luminescent Lanthanide Complexes." Molecules 25, no. 17 (2020): 4022. http://dx.doi.org/10.3390/molecules25174022.
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Europium, terbium, dysprosium, and samarium are the main trivalent lanthanide ions emitting in the visible spectrum. In this work, the potential of these ions for colorimetric applications and colour reproduction was studied. The conversion of spectral data to colour coordinates was undertaken for three sets of Ln complexes composed of different ligands. We showed that Eu is the most sensitive of the visible Ln ions, regarding ligand-induced colour shifts, due to its hypersensitive transition. Further investigation on the spectral bandwidth of the emission detector, on the wavelengths’ accuracy, on the instrumental correction function, and on the use of incorrect intensity units confirm that the instrumental correction function is the most important spectrophotometric parameter to take into account in order to produce accurate colour values. Finally, we established and discussed the entire colour range (gamut) that can be generated by combining a red-emitting Eu complex with a green-emitting Tb complex and a blue fluorescent compound. The importance of choosing a proper white point is demonstrated. The potential of using different sets of complexes with different spectral fingerprints in order to obtain metameric colours suitable for anti-counterfeiting is also highlighted. This work answers many questions that could arise during a colorimetric analysis of luminescent probes.
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Jackson, D. Michael, H. F. Harrison, R. L. Jarret, and P. A. Wadl. "Phenotypic analysis of leaf colours from the USDA, ARS sweetpotato (Ipomoea batatas) germplasm collection." Plant Genetic Resources: Characterization and Utilization 17, no. 04 (2019): 325–38. http://dx.doi.org/10.1017/s1479262119000042.
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AbstractLeaf colour characteristics of 730 sweetpotato, Ipomoea batatas (L.) Lam. (Convolvulaceae), plant introduction (PI) accessions from the USDA sweetpotato germplasm collection were evaluated during 2012–2014. Colorimetry data for the abaxial and adaxial leaf surfaces were recorded using a tristimulus colorimeter and the CIE 1976 L*a*b* and CIE L*C*h* colour spaces. Most accessions (725 of 730 PIs) had dark-to-medium green leaves, but two PIs had totally purple leaves, and three PIs had yellow or yellow-green (chartreuse) leaves. For mature, field-grown green leaves, values for the red-green coordinate (a*) averaged −12.4 for the adaxial and −10.4 for the abaxial leaf surface. Values for the blue-yellow coordinate (b*) averaged 17.2 for the adaxial and 17.3 for the abaxial leaf surface. Hue angle (h*) for green leaves averaged 120.9° for the adaxial and 126.2° for the abaxial leaf surface. Colour saturation (Chroma, C*) averaged 21.3 for the adaxial and 20.2 for the abaxial leaf surface. Lightness (L*) averaged 35.4 for the adaxial and 47.2 for the abaxial leaf surface of green leaves. Late in the season, over one-half (53.9%) of the 730 PIs showed some level of purple pigmentation in the leaf lamina. Late-season purple leaves were collected and colour coordinates were recorded for 118 PIs grown in the field. For purple leaves, values for a*, b*, C*, L* and h* averaged 2.3, 6.2, 7.9, 28.2 and 64.4° for the adaxial surface and −1.0, 12.7, 13.9, 43.1 and 87.0° for the abaxial leaf surface, respectively.
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Padmasali, AN, and SG Kini. "LED life prediction based on lumen depreciation and colour shift." Lighting Research & Technology 49, no. 1 (2016): 84–99. http://dx.doi.org/10.1177/1477153515593580.
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Light emitting diodes, with advantages in energy savings, luminous efficacy and greater reliability, are becoming preferred over conventional white light sources. Currently, only light output depreciation is considered for life estimation of light emitting diode luminaires but it is recommended to include colour shift variations for applications demanding colour stability. In this paper, an extended Kalman filter is employed to determine L70 life and colour temperature degradation over life of a light emitting diode luminaire. The colour shift in terms of Duv is determined by statistical polynomial cure fitting. The variation in chromaticity coordinates over life is determined and life based on colour shift is determined by acceptable Duv limits. The results are compared to life determined by the IES-TM-21 method and the correlated colour temperature limits taken from the luminaire data sheet.
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Latal, Jan, Patrik Hanulak, Jakub Kolar, Zdenek Wilcek, Tomas Stratil, and Filip Sarlej. "Measurement of colour coordinates of LEDs used in the automotive exterior lighting." International Journal of Electrical and Computer Engineering (IJECE) 11, no. 3 (2021): 2711. http://dx.doi.org/10.11591/ijece.v11i3.pp2711-2724.
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Article deals with dichromatic white light-emitting diode (LED’s) color coordinates used in automotive exterior lighting. This article also describes basic white automotive LED functionality and basic physical processes that create white light of these LEDs. It focuses on measuring color coordinates of white automotive LEDs with different temperature of LED and how the LED’s color depends on LED’s temperature. The article is comparing very important datasheet information of LED producers and values measured in the laboratory at university. The article contains statistical results of measurements and graphical representation of measured values and declared color bins which are very important for producers of headlamps for automotive companies.
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Biernacka, Beata, Dariusz Dziki, Renata Różyło, and Urszula Gawlik-Dziki. "Banana Powder as an Additive to Common Wheat Pasta." Foods 9, no. 1 (2020): 53. http://dx.doi.org/10.3390/foods9010053.
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This study aimed to analyse the effect of dried banana powder (BP) on common wheat pasta characteristics. Wheat flour (type 500) was replaced with 1%, 2%, 3%, 4% and 5% of BP. Control pasta without BP addition was also prepared. Pasta quality parameters including texture, colour, cooking characteristics and sensory evaluation were determined. Total phenolics content and antioxidant activity were also evaluated. The increase in BP in the pasta recipe resulted in an increase in the weight increase index (from 2.88 to 3.55) and cooking loss (from 5.2% to 6.4%). The effects of the addition of bananas were also observed in changes in colour coordinates. It was shown that BP slightly decreased the lightness of cooked pasta and had little influence on colour coordinates of raw pasta. It was also found that the addition of BP higher than 3% decreased pasta firmness. The total phenolics content and antioxidant capacity of pasta increased with the addition of BP. Sensory evaluation of pasta showed that the replacement of common wheat flour with BP should not exceed 3%.