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The CIELAB color space diagram. The CIELAB, or CIE L* a* b*, color system represents quantitative relationship of colors on three axes: L* value indicates lightness, and a* and b* are chromaticity coordinates. On the color space diagram, L* is represented on a vertical axis with values from 0 (black) to 100 (white). The a* value indicates red-green component of a color, where þa* (positive) and Àa* (negative) indicate red and green values, respectively. The yellow and blue components are represented on the b* axis as þb* (positive) and Àb* (negative) values, respectively. At the center of the plane is neutral or achromatic. The distance from the central axis represents the chroma (C*), or saturation of the color. The angle on the chromaticity axes represents the hue (h o ). The L*, a*, and b* values can be transcribed to dermatological parameters. The L* value correlates with the level of pigmentation of the skin. The a* value correlates with erythema. The b* value correlates with pigmentation and tanning. CIE, Commission Internationale de l'Eclairage.
Source publication
Skin color evaluation contributes to assessment of an individual's cutaneous phenotype. Skin color changes provide important clues to disease progression or treatment response. Skin color is also a predictor of skin cancer risk. Melanin pigment, blood flow, skin thickness, and photoaging contribute to skin color. Melanin, hemoglobin, bilirubin, and...
Context in source publication
Context 1
... 1976 CIELAB measurements are found to correlate to skin color and related parameters, such as erythema (Brainard and Stockman, 2010;Del Bino and Bernerd, 2013;Everett et al., 2012). The CIELAB, or CIE L* a* b*, system is a threedimensional color-space consisting of three axes ( Figure 1). The L* axis is a gray scale with values from 0 (black) to 100 (white). ...
Citations
... CIELAB color space diagram (source:[6]) C. Color gamut Gamut refers to a range of colors a printing device can render using process inks. The full-tone process inks (cyan, magenta, and yellow) and their two color overprints (red, green, and blue) mark the six endpoints of a device gamut, as shown inFigure 4. ...
This research investigates the impact of ink sequences and paper substrates on color reproduction in offset printing. Through experimentation and analysis, we demonstrate how altering the sequence of ink application influences color gamut. The variations in color gamut depend on the ink transfer capabilities. The MYCK order allows the most extensive color gamut for the investigated conditions. However, the effect is less observed on uncoated paper due to its high absorbency, resulting in minimal changes in ink transfer processes. Furthermore, our study highlights a substantial difference in color gamut between coated and uncoated paper, emphasizing the importance of considering paper substrate for achieving desired color reproduction. This research provides valuable insights for optimizing color fidelity in offset printing processes.
... Amazingly, the b* values reported here increased more than twofold (p < 0.05), reinforcing the blue color gain. This increase occurred around the 42nd day ( Figure 1E,F), demonstrating the desired intonation According to Figure 1, the most affected parameter was L*, which clearly indicates a darkening in the colors [61]. This is a desirable result since the loss of luminosity implies stronger colors, which occurred around the 42nd day ( Figure 1E,F). ...
Naturally colored fermented foods currently represent the trend toward a global demand for healthier products. This work produced naturally blue and green ice creams using C-phycocyanin (C-PC) and spirulina residual biomass (RB). The ice creams were assessed based on microbiological analysis, color stability over 6 months, antioxidant activity before and after in vitro digestion, and sensory evaluation. Considering the microorganisms that must be analyzed in accordance with Brazilian legislation, no growth was detected during the storage period. L*, a*, and b* were maintained according to the expected colors. The blue color was intoned over the shelf life (SC-PC *b −9.46 to −19.44 and MC-PC *b from −9.87 to −18.04). The antioxidant activity of the fermented ice creams SC-PC and SRB increased from 15.4 to 41.3 and from 15.3 to 38.0 µM TE/g, respectively, after bioaccessibility analysis. The C-PC ice cream’s appearance received the highest rating, with 70.26% of volunteers expressing a strong preference, highlighting its attractiveness. However, there were no significant differences compared to control samples in the global acceptance. The RB ice cream presented lower results for flavor but moderate acceptance. Thus, these fermented ice creams presented color stability over 6 months, and their antioxidant activity increased after in vitro digestion, highlighting their biological potential.
... a Konica Minolta CM 700d spectrophotometer (Ramsey, N.J.) to measure light reflectance from pigmented and nonpigmented sites. The CM 700d measured the perceived color in CIELAB color space (L*, a*, b*) of the skin 10 and then used the LAB coordinates to determine the individual typology angle {ITA = atan[(L − 50]/b) × 180/π}, which has been shown to be a surrogate for melanin content and is used widely as an objective assessment of skin pigmentation. 11 Skin biopsies were obtained for histopathologic assessment. ...
Background
Free flap monitoring is more difficult in patients with dark skin because ischemia and congestion can be masked by pigmentation. For this reason, adjunct methods such as cutaneous near-infrared spectroscopy are of elevated importance in patients with highly pigmented skin. The purpose of this experiment is to determine if ViOpitx T.Ox performance is affected by cutaneous pigmentation.
Methods
Swine with naturally occurring areas of nonpigmented and pigmented skin were used. Pigmentation of each animal was assessed using spectrophotometry and histopathology. During normoxemia, tissue oxygenation (StO 2 ) measurements were taken of nonpigmented and pigmented skin using the T.Ox device. A bicolor pedicled rectus abdominis myocutaneous flap was raised, and T.Ox probe was adhered to adjacent areas of opposite coloration on the same flap. StO 2 was measured continuously during reversible episodes of flap ischemia and congestion (n = 4 swine, n = 6 flaps).
Results
There was not a significant difference between baseline StO 2 values of nonpigmented (49% ± 7.9%) and pigmented skin (47% ± 6.2%). The absolute change in StO 2 was significantly larger during both ischemia (6%) and congestion (16%) in nonpigmented skin compared with adjacent pigmented skin.
Conclusions
T.Ox detects flap ischemia and congestion in both highly pigmented and nonpigmented skin. However, surgeons need to be aware that StO 2 changes related to complete flap ischemia or congestion may be much more subtle than what is seen in nonpigmented skin. This study establishes a novel internally controlled porcine model that isolates the impact of skin pigmentation when assessing cutaneous devices measuring tissue oxygenation.
... For example, it has been known since 1990 [3] that skin color may affect measured SpO 2 , with pulse oximeters typically overestimating SaO 2 in dark skin in the presence of occult hypoxemia [4][5][6]. Skin color is impacted not only by melanin pigment but also by blood flow, skin thickness, and photoaging [7]. Other patient factors that can affect noninvasive pulse oximeter accuracy with optical sensors are anemia, skin temperature, tobacco use, and fingernail polish [8]. ...
Background
Over recent years, technological advances in wearables have allowed for continuous home monitoring of heart rate and oxygen saturation. These devices have primarily been used for sports and general wellness and may not be suitable for medical decision-making, especially in saturations below 90% and in patients with dark skin color. Wearable clinical-grade saturation of peripheral oxygen (SpO2) monitoring can be of great value to patients with chronic diseases, enabling them and their clinicians to better manage their condition with reliable real-time and trend data.
Objective
This study aimed to determine the SpO2 accuracy of a wearable ring pulse oximeter compared with arterial oxygen saturation (SaO2) in a controlled hypoxia study based on the International Organization for Standardization (ISO) 80601-2-61:2019 standard over the range of 70%-100% SaO2 in volunteers with a broad range of skin color (Fitzpatrick I to VI) during nonmotion conditions. In parallel, accuracy was compared with a calibrated clinical-grade reference pulse oximeter (Masimo Radical-7). Acceptable medical device accuracy was defined as a maximum of 4% root mean square error (RMSE) per the ISO 80601-2-61 standard and a maximum of 3.5% RMSE per the US Food and Drug Administration guidance.
Methods
We performed a single-center, blinded hypoxia study of the test device in 11 healthy volunteers at the Hypoxia Research Laboratory, University of California at San Francisco, under the direction of Philip Bickler, MD, PhD, and John Feiner, MD. Each volunteer was connected to a breathing apparatus for the administration of a hypoxic gas mixture. To facilitate frequent blood gas sampling, a radial arterial cannula was placed on either wrist of each participant. One test device was placed on the index finger and another test device was placed on the fingertip. SaO2 analysis was performed using an ABL-90 multi-wavelength oximeter.
Results
For the 11 participants included in the analysis, there were 236, 258, and 313 SaO2-SpO2 data pairs for the test device placed on the finger, the test device placed on the fingertip, and the reference device, respectively. The RMSE of the test device for all participants was 2.1% for either finger or fingertip placement, while the Masimo Radical-7 reference pulse oximeter RMSE was 2.8%, exceeding the standard (4% or less) and the Food and Drug Administration guidance (3.5% or less). Accuracy of SaO2-SpO2 paired data from the 4 participants with dark skin in the study was separately analyzed for both test device placements and the reference device. The test and reference devices exceeded the minimum accuracy requirements for a medical device with RMSE at 1.8% (finger) and 1.6% (fingertip) and for the reference device at 2.9%.
Conclusions
The wearable ring meets an acceptable standard of accuracy for clinical-grade SpO2 under nonmotion conditions without regard to skin color.
Trial Registration
ClinicalTrials.gov NCT05920278; https://clinicaltrials.gov/study/NCT05920278
... Then, we performed simple threshold segmentation and extracted data on seed variables using the feature manager tools following the methods previously described [11][12][13]42]. Through the features manager tools, multiple (>50) parameters were computed and obtained as quantitative readouts for seed traits, including size (area, length, and aspect ratio), shape, orientation, and seed coat pigmentation traits-CIELab L*, CIELab A*, and CIELab B* (Commission on Illumination CIE Standards) [42,43]. In the CIE color space, CIELab L* represents the lightness from black to white, 0 = black and 100 = white; CIELab A* represents a unique color form between magenta and green, the red/green axis; and CIELab B* represents a unique color from blue to yellow, the yellow/blue axis. ...
... In the CIE color space, CIELab L* represents the lightness from black to white, 0 = black and 100 = white; CIELab A* represents a unique color form between magenta and green, the red/green axis; and CIELab B* represents a unique color from blue to yellow, the yellow/blue axis. Other seed coat parameters obtained from the readouts included hue, saturation value (HSV), and color space based on red, green, and blue intensity [42,43], as previously described in seed quality, discrimination classification, and seed vigor assessments [12][13][14]44]. ...
Physical, physiological, and biochemical traits control critical seed functions such as
germination, longevity, persistence, and seedling establishment. These traits are diverse between and among species, and they are also controlled by the environment in which the seed originated. Therefore, screening seed traits and understanding their roles in seed functions is crucial to facilitate the economical use of resources in collecting, sorting, and conserving seed materials of agronomical
and ecological importance. We hypothesized the existence of physical and biochemical traits in sea oats seeds that can be used as proxies to predict viability and vigor to develop underpinnings for survival after non-optimal storage conditions. Using multispectral imaging and optical oxygen�sensing analyses, we evaluated the physical and biochemical traits of Uniola paniculata L. (sea oats)
seeds collected from the US Atlantic and Gulf coastlines. Our results showed that several traits correlate to aging stress survival in sea oats seeds. These results confirm the potential of using physical and biochemical screening to predict seed quality while offering insights into extended seed longevity periods. Therefore, exploring and analyzing the physical and biochemical properties of seeds could reveal salient markers that contribute to viability and longevity.
... Also, no changes were found between different staining liquids after 7 days. According to the acceptability threshold, clinically visible and acceptable changes were observed in TP 00 [37,38]. In LD, changes were found after 3 days, and in ALD, they were found after 24 h. ...
Background: New lithia-based glass–ceramics, including Advanced Lithium Disilicate (ALD), have become popular in dentistry. However, it is unclear if glazing protocols for ALD might compromise its surface or optical properties. Thus, evaluating color and translucency changes in ALD and traditional lithium disilicate (LD) is crucial. Methods: This study aimed to assess how different firing protocols affect the surface and optical properties of LD and ALD. Sixty disc-shaped specimens were prepared, divided into three subgroups based on firing protocols, and subjected to surface roughness analysis. Specimens were immersed in coffee, wine, and water for 7 days, and then brushed. Color and translucency were measured. Results: Firing protocols significantly influenced surface roughness in LD (0.09–1.39 µm) and ALD (0.05–0.88 µm). Color differences were observed in both LD and ALD after 7 days, with visible changes within clinically acceptable thresholds. Translucency remained stable across firing protocols and staining liquids. Conclusions: Varying firing protocols impact surface roughness and color stability in LD and ALD. Despite differences, color and translucency changes remained within acceptable clinical thresholds, suggesting both materials are suitable for dental applications. Therefore, this study reinforces the reliability and versatility of these materials in restorative dentistry.
... which is illustrated in Table 7. These materials can be used for commercial production, but their color variance occurs as perceived by printing and graphic professionals [45]. Fig. 13 shows the test color sample which is used to describe the color precision and fidelity. ...
The new, more energy-efficient lighting systems and high-quality displays for new age digital devices is the demand of the current generation. In this regard, focused and deliberated research has been done on transition metal complexes as effective building blocks for organic light-emitting diodes (OLEDs). The activity of divalent metallic compounds was investigated through spotlighting Co (II), Ni (II), and Cu (II) metal ions with guanidinium naphthoate as blue phosphors in OLEDs. Using spectroscopic and diffraction techniques, the phosphors produced at the optimal temperature were studied both structurally and thermally. Additionally, the target compound's photophysical investigations in a variety of organic solvents with differing polarities were examined, and the findings were presented. Because of their quick photoluminescence response time and high emission quantum efficiency, Ni (II) complexes have drawn specific attention. Ni (II) complexes precisely exhibit thermally activated delayed fluorescence (TADF) and found to be the most promising materials for future lighting technology. We compared the efficiencies of various complexes in this study to provide an overview of the development of OLEDs. To affirm the pertinency of the synthesized compounds as phosphors, studies like photoluminescence, correlated color temperature, color purity, Duv, and the Television Lighting Consistency Index (TLCI) were performed and their photometric properties were also deliberated. Ni (II) shows an magnificent luminescence character and maximum coloring index for light sources and found to be an essential component for OLEDs.
... The subjective evaluation utilised the Monk Skin Tone Scale [19], a 10-shade scale (Letters A-J) representing human skin colour. Objective measurement involved determining CIE Lab* values and Individual Typology (ITA) angle [20,21], from the transmitted spectrum shown in Fig. 5. Table 3 summarises the characterisation of the melanin slides using both the Monk Skin Tone Scale and the CIE Lab* colour space technique. Appendix 2 outlines the steps for quantitatively calculating colour information from the four transmitted spectra of melanin slides. ...
Pulse oximeters’ (POs) varying performance based on skin tones has been highly publicised. Compared to arterial blood gas analysis, POs tend to overestimate oxygen saturation (SpO 2 ) values for people with darker skin (occult hypoxemia). The objective is to develop a test bench for assessing commercial home and hospital-based POs in controlled laboratory conditions. A laboratory simulator was used to mimic different SpO 2 values (~ 70 to 100%). Different neutral density and synthetic melanin filters were used to reproduce low signal and varying melanin attenuation levels. Six devices consisting of commercial home (Biolight, N = 13; ChoiceMMed, N = 18; MedLinket, N = 9) and hospital-based (Masimo Radical 7 with Neo L, N = 1; GE B450 Masimo SET with LNCS Neo L, N = 1; Nonin 9550 Onyx II™, N = 1) POs were reviewed and their response documented. Significant variations were observed in the recorded SpO 2 values among different POs when exposed to identical simulated signals. Differences were greatest for lower SpO 2 (< 80%) where empirical data is limited. All PO responses under low signal and melanin attenuation did not change across various simulated SpO 2 values. The bench tests do not provide conclusive evidence that melanin does not affect in vivo SpO 2 measurements. Research in the areas of instrument calibration, theory and design needs to be further developed.
Graphical Abstract
... The, L*, a*, and b* values of the skin sites were measured using a spectrophotometer CM-2500d (Minolta, Tokyo, Japan) [33]. The individual typology angle (ITA°) representing skin color was calculated from the measured L* and b* values using the equation: ITA° = (arc tangent [(L* − 50)/b*])(180/π) [34,35]. The melanin index and erythema index were measured using the mexameter MX18 (Courage + Khazaka electronic GmbH, Cologne, Germany) [36]. ...
... The, L*, a*, and b* values of the skin sites were measured using a spectrophotometer CM-2500d (Minolta, Tokyo, Japan) [33]. The individual typology angle (ITA • ) representing skin color was calculated from the measured L* and b* values using the equation: ITA • = (arc tangent [(L* − 50)/b*])(180/π) [34,35]. The melanin index and erythema index were measured using the mexameter MX18 (Courage + Khazaka electronic GmbH, Cologne, Germany) [36]. ...
... In this study, when comparing skin color between different body parts or analyzing age-related changes in the skin color of each body part, it was found that the change in the a* value was greater than the change in the L* value, and the melanin index and erythema index differed or changed to similar degrees. This suggests that differences and changes in skin color may have been caused by a variety of factors, including the content of black melanin and other pigments, inflammatory responses, and blood circulation [35]. ...
Background/Objectives: Skin color is innately determined by race and other genetic factors, and it also undergoes acquired changes due to various intrinsic and extrinsic factors. Previous studies on skin color have mainly focused on the face, and research has recently expanded to other body parts. However, there is limited information about the age-dependent changes in the skin color of these body parts. The purpose of this study is to analyze the differences in skin color between various body parts and the changes in skin color of each body part with age. Methods: This study examined the skin color of 53 Korean women subjects evenly distributed in age from the 20s to 60s on several body parts: forearm, upper arm, elbow (extended or folded), knee (extended or folded), thigh, and shin. The lightness (L*), redness (a*), and yellowness (b*) were measured using a spectrophotometer, and the individual typology angle (ITA°) was calculated from the L* and b* values. The melanin index and erythema index were measured using the mexameter. Results: The results showed that the elbow skin had the lowest L* and ITA° values and the highest a* and b* values among the examined body parts, followed by the knee. The melanin index and erythema index were also high in the skin of these body parts. In the analysis of age-dependent changes in the skin color of various body parts, the forearm skin exhibited the most notable decrease in the L* and ITA° values and increases in the a* and b* values, followed by upper-arm skin. The melanin and erythema indices in the forearm also increased as the subjects aged, whereas those in the elbow and knee rather decreased with age. Conclusions: This study suggests that differences in intrinsic and extrinsic skin aging in various body parts may be expressed as different changes in skin color and raises the need for cosmetic and dermatological research to identify the physiological significance of these changes.
... In the CIE-L* a* b* system L* value represents the lightness ranging from 0 (black) to 100 (white), and a* and b* are chromaticity coordinates. In particular, a* represents red and green values, while b* represents yellow and blue components (Ly, Dyer, Feig, Chien, & Del Bino, 2020). The pancakes were placed on a clear worktable, and then the measurements were performed at five different points on the smooth pancake's surface. ...
This work focused on the nutritional and technological evaluation of pancakes fortified with increasing Acheta domesticus powder (AP) levels. Scientific literature underscores AP's potential as an ingredient in bakery formulations due to its notable fiber and protein content. Thus, we formulated different pancake samples by replacing wheat flour (WF) with 10, 20, and 30% of AP, denoted as AP10, AF 20, and AP30, respectively, alongside a control sample (CP). We evaluated Water Absorption Capacity (WAC) and Water Solubility Index (WSI) on WF, AP, different WF and AP mixes, and batters' rheology. Lastly, we assessed the pancakes' physical, technological, and compositional parameters. The consistency index, flow index, and density increased from CP to AP30. A similar trend was observed for the textural parameter of hardness and chewiness, while cohesiveness slightly decreased. The pancake diameter and height were higher in fortified samples than in CP. A noticeable shift from brighter to darker color was observed from CP to AP30, with an increase in the a* (toward red) and b* parameters (toward blue). AP can represent a valuable ingredient for baked good fortification.
