Measured Color Values Research Articles

COLOR DIVERSITY OF BEECH WOOD WITH A FALSE HEARTWOOD IN THE COLOR SPACE CIE L*a*b*

The color of the false heartwood of Fagus sylvatica L. perceived by the human eye is in a wide range of shades from light brown-yellow to red-brown. The article analyzes the color in the color space CIE L*a*b* of dry wood of the false heartwood type: round, flame, star and marble. The color of the wood was measured with a colorimeter Color reader CR-10. The most colorful is the wood marble with a false heartwood. The results of statistical processing of the measured color values of dry beech wood, marble false heartwood on a planed surface identify it with values on the lightness coordinate L* = 65.2 ± 6.9 and on the chromatic coordinates: red color a* = 13.2 ± 2.3 and yellow b* = 19.2 ± 1.9. The most homogeneous in color is the color of the ring wood of the false heartwood with the coordinate values: L* = 63.7 ± 3.1; a* = 12.6 ± 1.7 and b* = 20.1 ± 1.6. The color diversity of the darkness and yellow-brown-red shades of the wood of the false heartwood is numerically quantified by the values of the total color difference ΔEsx* = 3.9 - 7.5. The presented values of the color of false heartwood beech complement the knowledge about the color of false heartwood and by defining the boundaries of color in the color space CIE L*a*b*, they create space for designers to model the color diversity of compositions and construction-joinery products made of sapwood and false heartwood beech.

Encapsulated Colorimetric Indicators used as Additives During the Polymerization of Smart Polyethylene

AbstractA number of colorimetric pH indicators (phenolphthalein, bromocresol green, 4‐nitrophenol, phenol red, and bromothymol blue) are encapsulated within silica particles via an acid‐catalyzed sol–gel process. The fabricated indicator is added during ethylene polymerization with a metallocene (Cp2ZrCl2) catalyst. Introduction of the indicator into the silica matrix affects the surface area, probably by partially blocking some of the pores. The encapsulated pH indicator reduces the catalytic activity by up to 17%, whereas adding a solution of the indicator reduced the catalytic activity by up to 34%. The crystallinities of the samples containing the silica‐encapsulated pH indicators are lower than those of the samples to which the pH indicator is added in solution form. The prepared encapsulated colorimetric pH indicators are analyzed by diffuse reflectance UV‐vis spectroscopy. The measured color values are distributed according to the CIE Lab lightness psychometric color space. Addition of the indicator in solution form (free) to the ethylene polymerization reaction does not result in indicator activity in acidic or alkaline media. The pH indicators incorporated into the polyethylene show color changes when exposed to acidic and alkaline media. Samples to which the unencapsulated pH indicators (free) are added exhibit lower catalytic activities and higher crystallinities than the samples containing the encapsulated pH.

Introducing Spectrophotometry for Quality Control in Lithium‐Ion‐Battery Electrode Manufacturing

The demand for electrochemical storage systems is increasing due to their conventional use in mobile applications and potential as energy storage devices in power generation and electromobility. Due to its comparatively low weight and high energy density, the lithium‐ion battery is one of the most widely used electrochemical storage devices. Battery cell production consists of a complex process chain with a large number of interdisciplinary processes. Each process step has specific requirements for the product. Different process parameters are essential in each step and require unique control measurements to ensure the quality of the intermediate product. To identify critical parameters, an understanding of the potential effects of different process parameters and the relationship between structural characteristics and end product properties must be gained. Therefore, herein, spectrophotometry concerning its application in lithium‐ion battery production is investigated. Individual process steps in electrode production are carried out to establish a correlation between intermediate product properties and measured color values. The influences of the powder components, the dispersion, and coating process are discussed. Based on the experiments carried out in this study, the suitability of spectrophotometry as an indirect measurement method of intermediate product properties is demonstrated.

Optical effect of spraying l-menthol on gastric intestinal metaplasia visualized by linked color imaging.

Linked color imaging (LCI) enables noninvasive detection of gastric intestinal metaplasia (GIM) as a lavender color sign (LCS), and there has been a recent report that l-menthol enhanced GIM with LCI. We measured color values of GIM and surrounding mucosa with white light imaging (WLI), LCI and LCI after spraying l-menthol (Mint-LCI) and investigated the effect of l-menthol on gastric mucosa. Endoscopic images of the antrum with WLI, LCI and Mint-LCI from 18 patients were prepared. Each of six regions of interest (three points of GIM and three points of surrounding mucosa) was selected for each modality, and CIE1976 (L*a*b*) color space was used to measure the color values. The primary endpoint was color differences (ΔE) between GIM and surrounding mucosa in each modality. For surrounding mucosa, the mean a* value with Mint-LCI was significantly higher than the mean values with WLI and LCI (P < 0.01). The mean b* value of GIM with LCI was significantly lower than that of surrounding mucosa, and spraying l-menthol decreased the b* values of GIM with a change to a deeper lavender color (LCI: 10.0 ± 5.8, Mint-LCI: 3.7 ± 6.1, P < 0.01). However, there was no significant difference in mean ΔE values between LCI and Mint LCI (LCI: 21.1 ± 6.6, Mint-LCI: 22.7 ± 5.4, NS). After spraying l-menthol, the microstructure of GIM changed to translucent and microvessels were obscured. As shown by LCI, spraying l-menthol optically enhances the color of GIM in the antrum.

Effects of tarragon essential oil on some characteristics of frankfurter type sausages

Tarragon (Artemisia dracunlus) essential oil was obtained from fresh leaves by hydrodistillation. The isolated essential oil was added to frankfurter type sausages at a concentration of 0.1% (v/w). Samples without the essential oil were used as control. The effects of the addition of the tarragon essential oil on the sensory properties, such as odor, color intensity, flavor, spiciness, hardness and overall acceptance of the sausages were evaluated using a hedonic scale and compared to the control. In addition to the hedonic test, a sensory triangle test was conducted. The CIE L*, a* and b* values of the samples were also measured. The addition of the essential oil did not cause any changes in the odor, color intensity, and hardness of the frankfurters. The spiciness of the frankfurter samples added with the essential oil was higher than the control. However, the flavor and overall acceptability of the control samples were higher compared to that of the essential oil containing samples. The difference between the treatments was also significant according to the triangle test. The addition of the tarragon essential oil did not cause any changes in the instrumentally measured color values of the sausages.

Effects of Different Hydrocolloids on the Texture Profile of Chicken Meat Emulsions

The aim of the study was to produce chicken breast meat emulsions with the addition of different hydrocolloids that would have comparable, or better, textural properties to those produced with phosphates (E 450-452). We prepared 10 emulsions from mechanically separated chicken breast meat (as three experimental repetitions) with the additions of: phosphates (control; 0.7%), and three different levels of carrageenan and xanthan (0.5%, 0.8%, 1%), and of potato starch (1%, 1.5%, 2%). Instrumental measurements of colour (CIE L*, a*, b*) and texture (texture profile analysis, stress relaxation tests) were performed, along with evaluation of the sensory attributes (descriptive analysis). These chicken breast meat emulsions with different hydrocolloids significantly differed in their instrumentally measured colour values and most texture parameters (hardness, cohesiveness, gumminess, chewiness, resilience, F0, Y30), and in some of the sensory attributes (colour, firmness, aroma). The increases in carrageenan and potato starch additions affected some of the measured colour values and the sensory attributes, although the measured texture parameters were not affected. The increases in xanthan addition showed changes for the colour, texture and sensory profiles. These chicken breast meat emulsions with phosphate (0.7%), carrageenan (0.5%, 0.8%) and potato starch (2.0%) were most similar in colour, texture and aroma. Those with potato starch showed non-significant trends for improved attributes compared to the control group, due to their intense aroma.

Evaluating Abstract Art: Relation between Term Usage, Subjective Ratings, Image Properties and Personality Traits

One of the major challenges in experimental aesthetics is the uncertainty of the terminology used in experiments. In this study, we recorded terms that are spontaneously used by participants to describe abstract artworks and studied their relation to the second-order statistical image properties of the same artworks (Experiment 1). We found that the usage frequency of some structure-describing terms correlates with statistical image properties, such as PHOG Self-Similarity, Anisotropy and Complexity. Additionally, emotion-associated terms correlate with measured color values. Next, based on the most frequently used terms, we created five different rating scales (Experiment 2) and obtained ratings of participants for the abstract paintings on these scales. We found significant correlations between descriptive score ratings (e.g., between structure and subjective complexity), between evaluative and descriptive score ratings (e.g., between preference and subjective complexity/interest) and between descriptive score ratings and statistical image properties (e.g., between interest and PHOG Self-Similarity, Complexity and Anisotropy). Additionally, we determined the participants’ personality traits as described in the ‘Big Five Inventory’ (Goldberg, 1990; Rammstedt and John, 2005) and correlated them with the ratings and preferences of individual participants. Participants with higher scores for Neuroticism showed preferences for objectively more complex images, as well as a different notion of the term complex when compared with participants with lower scores for Neuroticism. In conclusion, this study demonstrates an association between objectively measured image properties and the subjective terms that participants use to describe or evaluate abstract artworks. Moreover, our results suggest that the description of abstract artworks, their evaluation and the preference of participants for their low-level statistical properties are linked to personality traits.

Robust Color Extrapolation with Median Matrices

Color extrapolation is the estimation of color coordinates or transforms for values that lie beyond the sampled colors or training data. For example given a chart of measured color values and a digital image of that chart it is useful to be able to extrapolate values that are beyond the color samples provided by the chart. One option is to use linear multivariate regression based on a sampling of nearby points. This will result in a matrix transform which can be used for extrapolation. This abstract proposes the derivation of a median matrix based on a sampling of nearby points. That is given random triplets of points a closed form inverse of the first order polynomials is used to directly compute matrix elements. The final matrix is determined by the median of the individual elements. The median matrix extrapolation is shown to be more accurate than conventional multivariate regression, more robust to noise, does not require linear algebra, and can potentially be applied to streaming data.

Oxidative stability of n-3-enriched chicken patties under different package-atmosphere conditions

The oxidation processes were studied in chicken patties, enriched with n-3 fatty acids, after 8days of storage at 4°C, under different aerobic conditions, and following heat treatment. Significant effects were seen on lipid and cholesterol oxidation and the sensory qualities for whole flaxseed addition in the chicken feed (i.e., n-3 fatty acid enrichment), and for the different package-atmosphere conditions. For the raw chicken patties, n-3 enrichment increased the colour L∗ values while, after the heat treatment, there were higher thiobarbituric acid-reactive substances (TBARs) and cholesterol oxidation products (COPs), and the rancidity was more pronounced. In comparison with the low O2 (<0.5%) package-atmosphere condition, O2 enrichment (80%) increased the instrumentally measured colour values, TBARs, total and individual COPs, and the rancidity became pronounced. The most suitable package-atmosphere condition of these raw n-3-enriched chicken patties is a very low O2 atmosphere, with or without an O2 scavenger.

Using a Digital Camera to Identify Colors in Urban Environments

A method for identifying colors in urban environments using a digital camera was established. Color analysis of images was performed using the CIELAB color space. The color coordinates were used to produce a color chart of prevailing colors in the area, which was later used to design a textile pattern. Color samples were in good agreement with the perceived colors of the surroundings. Neutral colors in gray tones predominate in the majority of the city of Ljubljana, Slovenia; nevertheless, there are also bright colors, notably green, yellow, and beige. The method described is fast and reliable enough to identify colors in urban environments. However, the analysis of a large number of photographs is needed to ensure objective results. To obtain reliable results for measured color values, it is necessary to exactly define the conditions under which photographs were taken . 2011 Society for Imaging Science and Technology.

Optical spectroscopy as a rapid and low-cost tool for the first-line analysis of glass artefacts: a step-by-step plan for Roman green glass

Archaeometric research on glass artefacts is continuously evolving and is converging towards a multidisciplinary research domain where different types of techniques are applied depending on the questions asked and the circumstances involved. The technique described in this work is optical spectroscopy. The benefit of this technique being the possibility of building up a knowledge database for a large amount of material in a relatively short period of time and with a relatively limited budget. This is of particular interest for the investigation of extensive and/or unexplored glass collections where a first-line analysis of artefacts could facilitate the selection of material needing further and more detailed examination. This publication explores the extent to which optical spectroscopy can be used for a first-line analysis of green coloured glass artefacts from the Roman period. It is shown that the colour coordinates calculated from the measured transmission spectrum could reveal information about the fragment under study. In particular it is shown that 1) based on the position of the calculated colour values on the colour diagram (CIE1931) one could easily know whether the artefact was coloured using only iron or if copper oxides were also present. In the case of the artefact owing its colour solely to the presence of iron, the distance between the measured colour values and the colour diagram’s white point can roughly indicate the iron concentration of the sample; 2) artefacts that were fabricated under similar furnace conditions can also be identified on the colour diagram; 3) samples with identical compositions and fabrication conditions but with different sample thickness, gave rise to a variation in the colour coordinates, thus allowing optical spectroscopy to help identify fragments which might belong to the same object.

Measurment of Copper Concentration in ACQ, CUAZ, and CB-HDO Solutions by Using a Spectrophotometer

This research was performed to develop the simple techniques to predict the copper concentration in alkaline copper quat (ACQ), copper azole (CUAZ), and bis-(N-cyclohexyl-diazeniumdioxy)-copper (CB-HDO) solutions. Two simple methods measuring the color due to copper compounds were evaluated by using a spectrophotometer. One is to directly measure the color of the preservative solutions. The other is to measure the color developed on the surface of a treated sample with the preservatives. The <TEX>$L^*$</TEX> of the measured color values appeared to be the most sensitive to the change of copper concentration. The <TEX>$a^*$</TEX> values of the preservative solutions tended to be decreased at above a certain concentration condition, and the <TEX>$b^*$</TEX> values showed no trend with the concentration of copper compounds in preservative solutions. The surface color of the treated samples were changed from bluish to greenish as time passed. Both methods showed the high <TEX>$R^2$</TEX> values of the regression models determined by using the lightness, which suggested that the methods might be applicable in preservative-treatment mills for the easy and fast prediction of the copper concentration.

Colorimetric analysis of unstained lesions surrounding oral squamous cell carcinomas and oral potentially malignant disorders using iodine

To determine whether the measurement of staining with 3% Lugol's solution provided efficient criteria for determining the area of resection for oral carcinomas and oral potentially malignant disorders, the authors analyzed the color of unstained lesions (USLs) in relation to histopathological findings. After vital iodine staining, USLs were seen in 48 of 54 patients (88.9%). A significant difference was seen in the value of lightness between stained lesions (SLs) and USLs for patients with moderate and severe epithelial dysplasia (P<0.001). The deviation between the macroscopically observable and the histopathological boundaries was -0.65+/-1.26 mm (range: -4.36 to 1.52). Color charts prepared on the basis of values for lightness and hue reproduced the macroscopic color differences in USLs, suggesting that it may become possible to diagnose USLs histologically on the basis of the measured color values and use of color charts to help determine the resection area in surgery.

Effects of dietary astaxanthin concentration and feeding period on the skin pigmentation of Australian snapperPagrus auratus(Bloch &amp; Schneider, 1801)

A single-factor experiment was conducted to investigate the effects of dietary astaxanthin concentration on the skin colour of snapper. Snapper (mean weight=129 g) were held in white cages and fed one of seven dietary levels of unesterified astaxanthin (0, 13, 26, 39, 52, 65 or 78 mg astaxanthin kg −1 ) for 63 days. Treatments comprised four replicate cages, each containing five fish. The skin colour of all fish was quantified using the CIE L * , a * , b * colour scale after 21, 42 and 63 days. In addition, total carotenoid concentrations of the skin of two fish cage−1 were determined after 63 days. Supplementing diets with astaxanthin strongly affected redness (a *) and yellowness (b * ) values of the skin at all sampling times. After 21 days, the a * values increased linearly as the dietary astaxanthin concentration was increased before a plateau was attained between 39 and 78 mg kg −1 . The b * values similarly increased above basal levels in all astaxanthin diets. By 42 days, a * and b * values increased in magnitude while a plateau remained between 39 and 78 mg kg −1 . After 63 days, there were no further increases in measured colour values, suggesting that maximum pigmentation was imparted in the skin of snapper fed diets >39 mg kg −1 after 42 days. Similarly, there were no differences in total carotenoid concentrations of the skin of snapper fed diets >39 mg kg −1 after 63 days. The plateaus that occurred in a * and b * values, while still increasing in magnitude between 21 and 42 days, indicate that the rate of astaxanthin deposition in snapper is limited and astaxanthin in diets containing >39 mg astaxanthin kg −1 is not efficiently utilized. Astaxanthin retention after 63 days was greatest from the 13 mg kg −1 diet; however, skin pigmentation was not adequate. An astaxanthin concentration of 39 mg kg −1 provided the second greatest retention in the skin while obtaining maximum pigmentation. To efficiently maximize skin pigmentation, snapper growers should commence feeding diets containing a minimum of 39 mg unesterified astaxanthin kg −1 at least 42 days before sale.

Effects of ageing and low internal temperature of grilling on the formation of heterocyclic amines in beef Longissimus dorsi muscle

The mutagenic heterocyclic amines (HAs) originate in processed proteinaceous food. The effects of ageing (non-aged – i.e. 24 h post mortem vs. 14 and 28 days post mortem kept at 1 °C) and final internal temperature on cooking ( T i, 65 and 80 °C) on the content of HAs in grilled steaks (two-plated grill, temperature of 220 °C) were studied. HA precursors (creatine, creatinine, and free amino acids) and ageing indicators, such as instrumentally measured colour values, pH ultimate values and length of myofibrilar fragments on raw and cutting values on grilled beef Longissimus dorsi muscles were determined. The muscles originated from eight commercially slaughtered Simmental bulls, 19–20 months old. The content of HAs was determined by a solid-phase extraction procedure. Meat ageing is accompanied by large changes in the chemical composition and structure of muscle tissues. In general, all the ageing indicators and precursors of HAs were influenced by ageing time at the 5% level or less. Creatine content declined significantly (non-aged: 6.00 mg g −1, 14 days: 5.82 mg g −1, and 28 days: 5.55 mg g −1) and creatinine increased with days of ageing (non-aged: 0.19 mg g −1, 14 days: 0.24 mg g −1, and 28 days: 0.26 mg g −1). Higher contents of total free amino acids were determined after 14 and 28 days of storage (28.18 μmol g −1 and 37.59 μmol g −1) than in non-aged beef (19.00 μmol g −1). In this study, two HAs were determined: MeIQx (2-amino-3,8-dimethyl-imidazo[4,5-f]quinoxaline) and PhIP (2—amino-1-methyl-6-phenylimidazo-[4,5-b]pyridine). The content of HAs increases with ageing. At lower T i, more MeIQx was formed; at higher T i, more PhIP was formed. MeIQx was present in all samples while PhIP was found only in samples grilled to higher T i. Samples treated to T i = 80 °C generally contained less HAs (non-aged meat: 0.20 ng g −1, 14 days: 0.26 ng g −1, and 28 days: 0.28 ng g −1) than samples treated to T i = 65 °C (non-aged meat: 0.19 ng g −1, 14 days: 0.36 ng g −1, and 28 days: 0.39 ng g −1) on account of MeIQx thermolability.

Various instrumental and biochemical parameters as ageing indicators of beef Longissimus dorsi muscle and their relation to creatine and creatinine content

The main dietary source of creatine is red meat. Its ageing is accompanied by deep changes in chemical composition and structure of muscle tissues. The effect of ageing (nonaged—i.e. 24 h post mortem vs. 14 and 28 days post mortem at 1 °C) on the content of creatine and creatinine, on the creatine/creatinine ratio and on other ageing indicators, such as instrumentally measured colour values, pHultimate values, length of myofibrilar fragments and total free amino acid content of beef Longissimus dorsi muscle. Muscles originated from eight commercially slaughtered Simmental bulls, 19–20 months old. Generally, all parameters measured were influenced by ageing time at the 5% level or less. Approximately 0.1 unit higher pH values and 1 unit higher colour L *, a * and b * values of ageing samples compared to nonaged was found. Length of myofibrilar fragments being in average the highest (69 μm) for nonaged samples, 34 μm for 14 days aged and the lowest (17 μm) for 28 days aged sample. Higher content of total free amino acids released during 14 and 28 days of storage (10.19 and 18.71 μmol/g) than from nonaged beef (19.75 μmol/g) was found. Creatine content significantly declined with increasing days of ageing (nonaged 6.05 mg/g, 14 days 5.86 mg/g, 28 days 5.66 mg/g). On the contrary, the total content of creatine (creatine + 1.159 × creatinine) was not markedly affected by 14 days of ageing (nonaged 6.27 mg/g, 14 days 6.14 mg/g), although significant difference between nonaged and 28 days aged groups (5.95 mg/g) was observed. It was assumed that the creatinine/creatine ratio might be a good indicator of ageing rate for beef (R 2 = 0.974).

COTTON-COLOR INSTRUMENTATION ACCURACY: TEMPERATURE AND CALIBRATION PROCEDURE EFFECTS

Government cotton classing offices and gins with state-of-the-art process-control systems conduct automatedcotton-color measurements. Calibration of the color instrumentation involves the use of five colored ceramic tiles asreferences for input to a multiple-linear-regression model. In this study, two commercial color-measurement instrumentsrecorded color values of a set of 18 colored ceramic tiles at various time intervals. The effects of calibrating with fewer ofthe calibration tiles, of using a simpler calibration algorithm, and of temperature fluctuation, were determined regardinginstrument accuracy. Both methods of simplifying calibration (reducing the number of tiles and using a simple-linearmodel) had the same effect: better accuracy in the brightness measurement (Rd) and lower accuracy in the yellownessmeasurement (+b). Whereas +b is the more critical measurement, the multiple-linear model with four or five tiles issuperior overall. However, the difference is not so great as to render the simple-linear model with only two tilesinadequate in a process-control system that demands greater simplicity. Temperature changes were found to be correlatedwith changes in measured color values. The measured value of Rd trended downward with increasing temperature, butthere was no predictable trend in measured +b. Use of similar color instrumentation in a cotton gin would require somemethod of compensation for temperature effects.

Color measurements of minerals and mineralized froths

Color measurements were made for pure minerals mineral mixtures and flotation froths loaded with different minerals. The research objective was to correlate color with the composition of mineral streams. An industrially available system consisting of a fiber-optic-based illuminator and detector was used to measure color. The color values of binary mineral mixtures varied according to the type and proportion of minerals in the mixture. The measured color values of mineralized froths in the laboratory and in a commercial flotation circuit were dependent on the amount and type of minerals present.

2—THE EFFECT OF DRYING FOR A YIELD TEST ON THE COLOUR OF WOOL

Wool samples from a yield test on greasy wool are liable to be slightly discoloured by the specified drying procedure at 105°C. The downward bias in the measured colour values is both variable and, usually, unknown. Such samples are therefore unsuitable for colour-measurement purposes unless an unknown and variable bias can be tolerated.