Chromatic Changes Research Articles

Effect of chemical and physical pretreatments on the convective drying of cape gooseberry fruits (Physalis peruviana)

Drying of cape gooseberry fruits is a slow process because of the low permeability to moisture of the fruit’s waxy skin. In this work, the effect of chemical pretreatments (sunflower oil/K2CO3 or olive oil/K2CO3 at 28°C, and NaOH/olive oil at 96°C) and physical pretreatments (blanching) to break down the waxy surface and accelerate moisture diffusion during drying, was assessed. Drying was carried out at 60°C and 2m/s air velocity for 10h. The lowest moisture content (0.27kg water/kgdb), the highest vitamin C content (0.36mg/g), and the greatest rehydration capacity (1.89) were obtained in fruits pretreated with olive oil (9.48%) and K2CO3 (4.74%). However, the greatest changes in color (ΔE*=15.05) and chroma (ΔC*=9.03) were also associated to fruits pretreated with olive oil and K2CO3. The effective diffusivity of water during drying was 7.37×10−11m2/s in pretreated samples compared with 6.61×10−11m2/s for untreated samples.

Spotting biomarkers of pulmonary tuberculosis in human exhaled breath using porphyrin based sensor array.

In search of a rapid point-of-care diagnostic tool for the diagnosis of pulmonary tuberculosis (P-TB) this exhaled breath analysis study was conducted using porphyrin based sensor. A single total exhaled breath test was done on 62 participants, 32 P-TB cases and 30 healthy controls using sensor plate comprising of 24 coded porphyrin elements; Red, Green and Blue (RGB) analysis was done pre and post exposure. Different porphyrin derivatives exhibited varied RGB responses. Seven analytes in our sensor array showed notifiable responses to differentiate diseased from healthy in accuracy parameters: sensitivity was finest in three IB, IIBa, ICh, then IAb and ICd; in specificity ICa was best; Fair positive predictive value was in ICa, IIBa, ICd, I, IAb, ICh; likelihood ratio was not encouraging. ICa, IIBa, IB, IAb demonstrated fairly strong post-exposure chromatic changes in binary logistic regression. In our study, porphyrin array-based chemical sensing showed promising results for the direct diagnosis of pulmonary tuberculosis. The quality of interaction with organic volatile compounds can be controlled by suitable changes in the porphyrin macrocycle like peripheral substituent and central metal. This would lead to fine tuning of senor array by identifying responsive porphyrin derivatives with better predictive value and incorporation them in a single array for enhanced responses. It would be worth evaluating colorimetric porphyrin elements based sensor array in more detail as a likely cost-effective futuristic model of non-invasive entrant in diagnostic algorithms to halt the pandemic of tuberculosis.

Effect of Wavelength-dependent Scattering on the Color Chromaticity of the LCD Backlight

The effect of the wavelength-dependent scattering on the change of the color chromaticity in the lightguide panel of a liquid crystal display is examined. The white light emitted from the white LEDs located at the edge of the lightguide propagates in the lightguide and is scattered by the patterned dots that are placed on the bottom of the lightguide. The scattered lights that are far from the LEDs showed reddish color compared to the bluish color that is scattered from the near area from the LEDs. The color difference was between 0.01 to 0.06 depending on the resin and the thickness of the lightguide.

Chromatic changes to artificial irises produced using different techniques

Ocular prostheses are important determinants of their users' aesthetic recovery and self-esteem. Because of use, ocular prostheses longevity is strongly affected by instability of the iris color due to polymerization. The goal of this study is to examine how the color of the artificial iris button is affected by different techniques of artificial wear and by the application of varnish following polymerization of the colorless acrylic resin that covers the colored paint. We produce 60 samples (n = 10) according to the wear technique applied: conventional technique without varnish (PE); conventional technique with varnish (PEV); technique involving a prefabricated cap without varnish (CA); technique involving a prefabricated cap with varnish (CAV); technique involving inverted painting without varnish (PI); and technique involving inverted painting with varnish (PIV). Color readings using a spectrophotometer are taken before and after polymerization. We submitted the data obtained to analyses of variance and Tukey's test (P < 0.05). The color test shows significant changes after polymerization in all groups. The PE and PI techniques have clinically acceptable values of ΔE, independent of whether we apply varnish to protect the paint. The PI technique produces the least color change, whereas the PE and CA techniques significantly improve color stability.

The “Alpalhão Granite” (Alentejo, Portugal) as a Potential Ornamental Stone

“Alpalhão granite”, also called SPI, is used as a high quality ornamental stone for interior and exterior applications. It is fine grained and equigranular, and has disseminated feldspar phenocrysts showing a homogeneous bluish grey colour. The SPI was mapped and scanlines (14) and drill cores (4) were carried out for lithofacies and joints characterization, besides petrographical study. Three of the 5 granite outcrops were studied regarding their potential for ornamental blocks exploitation (Carvalhal, Pinheiral and Ribeira de Sor). The Carvalhal area has generally no potential, due to intense fracturing and frequent heterogeneities except for drill core SCA1 area. The Pinheiral area has been exploited in all its extent, but still assures 368,800m3 estimated resources of good granite at depth. Ribeira de Sor area presents a good potentiality for commercial blocks in the eastern zone and a limited potential in the western area due to subsurface fracturing and chromatic changes.

Adjustment of Arrhenius activation energy of laccase-based time–temperature integrator (TTI) using sodium azide

When devising a time–temperature integrator (TTI), a chromatic color change indicator, Arrhenius activation energy (Ea) of TTI needs to coincide with that of the food in TTI packages. In this study, a new method of adjusting Ea of laccase-based TTI was developed by using NaN3 known to have a true inhibitory effect on laccase. An enzymatic prototype TTI was produced with laccase and formulated to have affordable reaction stability. NaN3 was treated in different concentrations and its effect on altering Ea was tested. A relationship between Ea of TTI vs. NaN3 concentration was established, and based on this relationship, the necessary amount of NaN3 to provide the laccase TTI for having the same Ea as was a given Ea of Pseudomonas fragi growth as a microbiological quality of model food was determined. Through storage tests, it turned out that the customized TTI with the Ea same as that of the model food could accurately predict the microbiological levels as compared to the TTI with lower or higher Ea. Consequently, the method of adjusting laccase-based TTI Ea with NaN3 added was found to be beneficial to design TTI fit for a particular food in TTI packages.

Iridophores and Not Carotenoids Account for Chromatic Variation of Carotenoid-Based Coloration in Common Lizards (Lacerta vivipara)

Abstract Carotenoids typically need reflective background components to shine. Such components, iridophores, leucophores, and keratin- and collagen-derived structures, are generally assumed to show no or little environmental variability. Here, we investigate the origin of environmentally induced variation in the carotenoid-based ventral coloration of male common lizards (Lacerta vivipara) by investigating the effects of dietary carotenoids and corticosterone on both carotenoid- and background-related reflectance. We observed a general negative chromatic change that was prevented by β-carotene supplementation. However, chromatic changes did not result from changes in carotenoid-related reflectance or skin carotenoid content but from changes in background-related reflectance that may have been mediated by vitamin A1. An in vitro experiment showed that the encountered chromatic changes most likely resulted from changes in iridophore reflectance. Our findings demonstrate that chromatic variation in carotenoid-based ornaments may not exclusively reflect differences in integumentary carotenoid content and, hence, in qualities linked to carotenoid deposition (e.g., foraging ability, immune response, or antioxidant capacity). Moreover, skin carotenoid content and carotenoid-related reflectance were related to male color polymorphism, suggesting that carotenoid-based coloration of male common lizards is a multicomponent signal, with iridophores reflecting environmental conditions and carotenoids reflecting genetically based color morphs.

An experimental study on the influence of surface finishing on the weathering of a building low-porous limestone in coastal environments

Limestones used as building material are especially prone to weathering in coastal environments due to interactions between sea mist and the carbonate stone. Subtle variations of the commercial surface finishing may lead to differences in decay patterns and aesthetic properties due to salt crystallization. To explore this potentially contrasting behavior, tablets of rough and polished low-porous limestone were aged in a sea-salt spray corrosion chamber to simulate their exposure in a coastal environment. Different crystallization morphologies and relative proportions of soluble (halite) and less soluble (gypsum) salts were observed in the aged rough and polished surface samples. These morphologies are ascribed to the microtextural characteristics and the surface pore systems of the diverse (rough and polished) substrates that in turn influence fluid (saline solution) transport toward their interior, as well as the different salt solubilities interacting with the substrates. Polished surfaces exhibit little evidence of damage after the ageing test in contrast to the rough samples but do have conspicuous gypsum on the surface together with halite. The scarcity of gypsum on the rough surfaces, in addition to a more severe change in the porosity system, suggests that salts penetrate deeper when the stone surface is not polished. Potential decay induced by salt crystallization pressure is therefore minimized when the stone surface is polished. However, polished surfaces show more significant changes in luminosity and chroma after the ageing test, and so are less attractive from an aesthetic point of view. Surface finishing is thus an important feature that needs to be characterized for a better understanding of the weathering behavior of building stones used in coastal environments.

Colouring Characteristics of Neem (Azadirachta indica) Bark Dye on Silk

The colours extracted from neem bark with different concentrations of mordants were tested on silk for the shades and colour fastness properties. The mordants tested were CuSO4, Al2(SO4)3, alum and citric acid. The colours of the fabrics were studied with a Hunterlab colour scale and the maximum AE* value (51.48±0.60) was observed for 1% CuSO4 mordant treated samples. However, the values were not significantly different from 2% and 3% CuSO4 treated samples. The unmordanted samples were also statistically acceptable in terms of AE* values. The change in chroma values were maximum for the 2% citric acid mordant (37.22±0.69), though the change in chroma offered by 2% and 3% alum, 3% citric acid and unmordanted samples were not significantly different. All the mordanted samples had fair to good (3–4) fastness to washing. The staining on undyed silk fabric with citric acid mordant showed excellent (5) fastness followed by alum and CuSO4 mordanted samples, which had good to excellent fastness. CuSO4 mordant offered good fastness to washing. The alum, Al2(SO4)3 and citric acid mordants exhibited excellent dry rubbing fastness whereas the CuSO4 mordant showed good to excellent (4–5) fastness. In case of wet rubbing, alum, citric acid and Al2(SO4)3 mordanted samples showed good to excellent (4–5) colour fastness. Colour fastness in case of CuSO4 mordant was good (4). The CuSO4 mordant offered fairly good (4) colour fastness to sunlight and all other mordants showed moderate (3) colour fastness. The samples without mordants exhibited poor fastness (2). In view of the colour fastness, viz. fastness for washing, rubbing and exposure to light, the neem bark dye should be applied with any of the mordants used for the study at 3% level.

Guest responsivity of a two-dimensional coordination polymer incorporating a cholesterol-based co-ligand

To implement specific guest responsivity, a hydrophobic cholesterol-based co-ligand, cholest-5-en-3-yl-4-isonicotinate (Cholpy), was incorporated into a two-dimensional Hofmann-type Co(II)Ni(II) coordination polymer. The chemically programmed structure successfully demonstrated the unique guest response with remarkable chromatic changes.

Dynamic dual stage phosphorescence chromatic change in a diborylated iridium phosphor for fluoride ion sensing with concentration discriminating capability

By adding a strongly electron-accepting B(Mes)2 group to the ppy-type ligand of phosphorescent iridium(III) cyclometalated complexes, more stabilized metal-to-ligand charge-transfer (MLCT) states can be obtained by transferring electron density from the pyridyl moiety to the boron atom of the B(Mes)2 group in the metallophosphors to give red phosphorescence. Taking advantage of the binding effect between boron atom and F− ion, the phosphorescent emission color of the iridium(III) cyclometalated complex can be dynamically changed by the external F− ions sequentially from red to yellow and to green through modulation of the charge-transfer emitting states, representing very unique F− ion sensing behavior. In the first step, destabilization of the MLCT states is caused by the weak binding between boron and F− ion, which is then accompanied by switching of the MLCT process to form high-energy MLCT states as induced by the strong binding between boron and F− ion in the second step. Not only does the dynamic phosphorescence chromatic variation depend significantly on the substitution mode of the B(Mes)2 moiety on the ppy ligands, but the dynamic emission response also would pave the way to the development of a novel F− ion sensor showing a unique concentration discrimination feature in aqueous solution with good color reversibility and optical response to the naked eye, high selectivity and sensitivity. All of these data provide valuable insight into the molecular design of a new generation of F− ion sensors featuring both concentration discriminating capability and good potential for practical applications.

미산성 전해수로 처리한 생식원료의 저장 중 미생물 저감 효과 및 색도 변화

본 연구에서는 생식 원료(현미, 보리, 당근, 감자, 신선초, 케일)를 미산성 전해수(SAEW)로 처리한 후 미생물 저감효과와 색도 변화를 측정하였다. 수돗물(TW)과 차아염소산나트륨수(NaOCl), SAEW 처리 간의 미생물 저감 효과와 색도 변화를 확인하기 위하여 각 저장온도(4, 10, 15, 20, 25, 30℃)와 저장기간(5, 10, 15, 20, 25, 30일) 동안 유통기한 연구로서 생식 원료를 저장한 후 변화를 확인하였다. 일반세균수는 생식원료 중 당근에서 가장 효과적인 저감효과를 나타냈으며 SAEW 처리가 NaOCl 처리보다 1.75 log CFU/g 더 감소하였다. 대장균군수는 보리에서 SAEW의 처리가 NaOCl 처리보다 1.54 log CFU/g 더 감소하여 생식 원료 중 가장 효과적인 저감효과를 나타내었다. 신선초와 케일에서 SAEW 처리는 lightness, redness, yellowness 값을 저하시켜 품질의 변화를 유지시킨 반면, 그 밖의 생식원료에서는 SAEW와 NaOCl 처리구간 효능의 차이는 없었다. 따라서 SAEW와 NaOCl 처리구간에 유의적인 차이(p<0.05)를 나타냈으며, 결과적으로 생식원료에 SAEW의 처리는 미생물학적으로 일반세균 및 대장균군수를 저감화시켜 저장기간 연장과 색도의 불변 효과를 나타냈으며 다른 품질의 변화 없이 생식의 원료를 효과적으로 위생처리가 가능함을 입증하였다.

발효 백미와 현미를 이용한 국수제조 및 품질특성

쌀을 이용하여 국수제조에 한계점을 개선하기 위하여 다양한 영양소를 함유한 현미를 사용하여 이를 발효한 후 국수를 제조하여 특성을 확인하였다. 국수는 백미와 현미를 이용하여 백미국수, 발효백미국수, 현미국수, 발효현미국수를 각각 제조하여 사용하였다. 제조된 국수의 일반성분 분석 결과 발효하였을 때 조단백질 함량은 증가 되었으며, 조지방, 탄수화물의 함량은 감소하였다. 또한 수분의 함량은 현미국수가 백미보다 2배 이상의 함량을 보였으며 발효하였을 때 약간 감소하는 것을 확인하였다. 색도는 발효함에 따라 약간의 변화는 있었으나 유의적인 차이는 나타나지 않았다. 조리시 중량, 부피는 증가하였으나 백미로 만든 국수에서 그 변화가 가장 낮았으며, 조리된 국물의 탁도는 백미로 만든 국수에서는 높게 나타났지만 다른 국수에서는 일정한 탁도를 나타내었다. 조리된 국수의 texture은 조리시에 수분의 함유로 조직이 부드러워짐에 따라 대부분 감소되었으나, 발효함에 따라 탄성도는 증대되었다. 따라서 영양학적 성분을 다량 함유하는 현미를 이용한 발효현미국수를 제조함으로서 쌀을 이용한 국수제조의 단점을 개선하고 현대인의 기호도에 적합한 쌀 가공식품으로의 개발이 가능하다고 사료된다. To address the limitations of manufacturing noodle products using rice, brown rice noodles were created by the fermentation of brown rice containing several nutrients and the quality of these noodles were evaluated. White rice noodles, fermented white rice noodles, brown rice noodles, and fermented brown rice noodles were developed using white rice and brown rice, respectively. We found that the content of crude proteins present in the noodles during the fermentation process increased and the content of crude fat and carbohydrates in the noodles was reduced. In addition, the water content of brown rice noodles was twofold higher than that of white rice, although under fermentation conditions, the water content of brown rice noodles decreased slightly. A slight change of chromaticity was observed during the fermentation process. In cooking, the weight and volume of the noodles increased, with the change being lowest in noodles based on white rice. White rice-based noodles exhibited significantly higher turbidity in the cooked noodle soup, while other noodle products showed relatively constant turbidity. Most of the products showed a decreased texture, becoming soft with cooking; however, the elasticity of the cooked products increased. Our results suggest that the disadvantages of producing rice noodles can be overcome by the development of fermented brown rice noodles containing a variety of nutritional components. This would potentially develop a market for rice-based manufactured foods that appeal to modern preferences.

Colorimetric study of the interactions between different families of red wine pigments using transmittance and reflectance measurements

The aim of this work was to conduct a detailed colorimetric study, using transmittance and reflectance measurements, to evaluate the possible interactions occurring among the different families of pigments comprising to colour matter of red wines and their contribution to the colour in aged red wines.To accomplish this, the phenolic material of monovarietal red wines obtained from Tempranillo and Graciano varieties, and their blends, were fractionated by gel permeation chromatography in order to separate the coloured fractions with different chemical compositions. The binary blends at different concentrations of the fractions having higher anthocyanin monoglucoside proportions with fractions having higher pyranoanthocyanin derivative contents and direct flavanol-anthocyanin condensation products were carried out in order to determine the effect of adding these derivatives on the colour of the anthocyanin monoglucosides, the major wine pigments. It was observed that the addition of derived pigments to the anthocyanin monoglucosides fraction resulted in colour differences perceptible by the human eye. These variations were mainly quantitative (changes in chroma and lightness), and were also qualitative (changes in hue) in monovarietal wines.Studying the phenolic fractions of wines implies an approach to the chemical reality of the wines, more than the studies on model solutions, since they can lead to the knowledge of those components having more influence on the final colour of the wine. With these results the wineries could conduct the vinifications towards a higher extraction of the components or families of components more important for the intensity and stability of colour.

Visualization of electroporation-induced temperature rise using temperature-sensitive ink

Irreversible electroporation (IRE) is attracting attention as a new technique to treat tumors, in which electric pulses over a certain threshold perforate the cell membrane and induce necrotic cell death. Since the electric pulses potentially generate the Joule heating around electrodes, successful IRE needs to apply a pulsed voltage high enough for the irreversible perforation yet minimizes the thermal effect on the extracellular matrix in the surrounding tissue. The temperature rise around the electrodes is therefore one of the most important concerns in the IRE. However, no experimental evidence has been reported for the temperature rise because of extremely short pulses used in the IRE. The aim of this study was therefore to establish a new method to detect the temperature rise during the IRE. A key technique is to use temperature-sensitive ink to visualize in situ instantaneous temperature rise. Chromatic change of the ink that depends on the temperature was preliminarily calibrated by a transient short-hot-wire technique combined with color analysis of the ink, and then utilized to determine the temperature distribution after electroporation. The maximum temperature rise was thus successfully visualized after the electroporation using agar gel as a tissue phantom. Our method is useful for direct evaluation of a risk of thermal damage and provides experimental evidence for theoretical study.

Microlensing of the broad line region in 17 lensed quasars

When an image of a strongly lensed quasar is microlensed, the different components of its spectrum are expected to be differentially magnified owing to the different sizes of the corresponding emitting region. Chromatic changes are expected to be observed in the continuum while the emission lines should be deformed as a function of the size, geometry and kinematics of the regions from which they originate. Microlensing of the emission lines has been reported only in a handful of systems so far. In this paper we search for microlensing deformations of the optical spectra of pairs of images in 17 lensed quasars. This sample is composed of 13 pairs of previously unpublished spectra and four pairs of spectra from literature. Our analysis is based on a spectral decomposition technique which allows us to isolate the microlensed fraction of the flux independently of a detailed modeling of the quasar emission lines. Using this technique, we detect microlensing of the continuum in 85% of the systems. Among them, 80% show microlensing of the broad emission lines. Focusing on the most common lines in our spectra (CIII] and MgII) we detect microlensing of either the blue or the red wing, or of both wings with the same amplitude. This observation implies that the broad line region is not in general spherically symmetric. In addition, the frequent detection of microlensing of the blue and red wings independently but not simultaneously with a different amplitude, does not support existing microlensing simulations of a biconical outflow. Our analysis also provides the intrinsic flux ratio between the lensed images and the magnitude of the microlensing affecting the continuum. These two quantities are particularly relevant for the determination of the fraction of matter in clumpy form in galaxies and for the detection of dark matter substructures via the identification of flux ratio anomalies.

Analysis of the surface of different marbles by X-ray photoelectron spectroscopy (XPS) to evaluate decay by SO2 attack

Atmospheric pollution is one of the main agents of decay in monuments and other works of art located in industrialised urban centres. SO2 is a permanent and abundant component of air pollution and, although it does not have an immediate visual effect, after continuous exposure, it can cause irreversible damage to building materials. Marble is one of the most commonly used ornamental stones in historical monuments and its mineralogical composition makes it very susceptible to damage caused by exposure to SO2. To measure the chemical reactions caused on marble by the action of atmosphere rich in SO2, selected calcitic and dolomitic samples were altered by weathering accelerated test. For this, seven marble types (four calcitic and three dolomitic) were exposed to high concentration of sulphur dioxide for 24 h in a climate chamber under controlled temperature and humidity conditions (20 °C and > 90 % HR). Changes on marble surfaces caused by reactions of SO2 with calcite and dolomite were studied using two non-destructive techniques: chromatic change by means of colorimetry and chemical analysis using X-ray photoelectron spectroscopy (XPS). The development of new mineral phases was also observed by scanning electron microscopy. Colorimetric analysis revealed a decrease in lightness and chromatic parameters suggesting that these changes were due to the development of new mineral phases in all marbles. The XPS technique, which is generally used in the analysis of metals, is relatively new in the field of stone deterioration. It enabled us to recognise the development of sulphites and sulphates on marble surfaces with high precision, after just 24 h of exposure to high SO2 concentrations and to distinguish different decay paths for calcitic and dolomitic marbles.

Geometry-invariant GRIN lens: iso-dispersive contours

A dispersive model of a gradient refractive index (GRIN) lens is introduced based on the idea of iso-dispersive contours. These contours have constant Abbe number and their shape is related to iso-indicial contours of the monochromatic geometry-invariant GRIN lens (GIGL) model. The chromatic GIGL model predicts the dispersion throughout the GRIN structure by using the dispersion curves of the surface and the center of the lens. The analytical approach for paraxial ray tracing and the monochromatic aberration calculations used in the GIGL model is employed here to derive closed-form expressions for the axial and lateral color coefficients of the lens. Expressions for equivalent refractive index and the equivalent Abbe number of the homogeneous equivalent lens are also presented and new aspects of the chromatic aberration change due to aging are discussed. The key derivations and explanations of the GRIN lens optical properties are accompanied with numerical examples for the human and animal eye GRIN lenses.

SU-E-I-21: Effect of Different Fluorescent Lights with Various Colors of a Reading Room on Chromaticity of LCD.

To examine variation of chromaticity of LCD in different types of fluorescent lights in a reading room. A color LCD (RX320, antiglare type, 450 cd/m2 , three-megapixel, Eizo Nanao), and a monochrome LCD (G31-S, anti glare type, 450 cd/m2 , three-megapixel, Eizo Nanao) were used in this study. The chromaticity in grayscale images with eighteen luminance levels were measured under five types of fluorescent lights with different color spectrums (Daylight: 6,700 K, Natural white: 5,000 K, White: 4,200 K, Warm white: 3,500 K, Light bulb: 3,000 K) by using a colorimeter (CS-200: KONICA MINOLTA). The chromaticity of LCDs was measured at various ambient lighting conditions (a dark room, 36, and 300 lux) and different types of fluorescent lights. The chromaticity of LCDs measured under ambient lights was changed from that measured in a dark room. The chromaticity of LCDs varied with different types of fluorescent lights. As illuminance of the room increased, variations in chromaticity at relatively lower luminance levels increased. The direction of changes in chromaticity shifted to the color for each fluorescent light. Fluorescent lights having different color spectra affect the chromaticity of LCDs.

Color constancy investigated via partial hue-matching

Each hue is believed to be made up of the four component hues (yellow, blue, red, and green). A hue consisting of just one component hue is called unitary (or unique). A new technique--partial hue-matching--has been used to reveal the component and unitary hues for a sample of 32 Munsell papers, which were illuminated by neutral, yellow, blue, green, and red lights and assessed by four normal trichromatic observers. The same set of four component hues has been found under both the neutral and the chromatic illuminations for all of the observers. On average, more than 87% of the papers containing a particular component hue under the neutral illumination also have this component hue when lit by the chromatic lights. However, only a quarter of the papers perceived as unitary under the neutral illumination continues being perceived as unitary under all of the chromatic illuminations. In other words, most unitary colors shift along the hue circle due to change in an illuminant's chromaticity. Still, this shift of unitary colors is relatively small: On average, it does not exceed one Munsell hue step.