• The Journal of Advanced Prosthodontics
• /
• v.5 no.3
• /
• pp.262-269
• /
• 2013

PURPOSE. Perceived color of ceramics changes by the spectral power distribution of ambient light. This study aimed to quantify the amount of shifts in color and color coordinates of clinically simulated seven all-ceramics due to the switch of three ambient light sources using a human vision simulating spectroradiometer. MATERIALS AND METHODS. CIE color coordinates, such as $L^*$, $a^*$ and $b^*$, of ceramic specimens were measured under three light sources, which simulate the CIE standard illuminant D65 (daylight), A (incandescent lamp), and F9 (fluorescent lamp). Shifts in color and color coordinate by the switch of lights were determined. Influence of the switched light (D65 to A, or D65 to F9), shade of veneer ceramics (A2 or A3), and brand of ceramics on the shifts was analyzed by a three-way ANOVA. RESULTS. Shifts in color and color coordinates were influenced by three factors (P<.05). Color shifts by the switch to A were in the range of 5.9 to 7.7 ${\Delta}E{^*}_{ab}$ units, and those by the switch to F9 were 7.7 to 10.2; all of which were unacceptable (${\Delta}E{^*}_{ab}$ > 5.5). When switched to A, CIE $a^*$ increased (${\Delta}a^*$: 5.6 to 7.6), however, CIE $b^*$ increased (${\Delta}b^*$: 4.9 to 7.8) when switched to F9. CONCLUSION. Clinically simulated ceramics demonstrated clinically unacceptable color shifts according to the switches in ambient lights based on spectroradiometric readings. Therefore, shade matching and compatibility evaluation should be performed considering ambient lighting conditions and should be done under most relevant lighting condition.

• Journal of the Korean Ceramic Society
• /
• v.55 no.4
• /
• pp.368-375
• /
• 2018

This study deals with the color formation of ceramic pigment in the $TiO_2$-SnO-ZnO system. We designed compounds to control the color formation depending on the composition using the Design of Experiment. The color coordinate values of synthesized pigments, $L^*a^*b^*$ were measured and statistically analyzed color for changing elements depending on its composition. The relationship between the major crystalline phases and chromaticity was examined using XRD, and the oxidation states of each element were analyzed by XPS. The synthesized pigments based on the compound design exhibited various color changes ranging from yellow-orange to green-blue and brown. The statistical analysis on the spectrophotometer results shows that $a^*$ and $b^*$ values decreased with $TiO_2$ content, and increased with SnO content. Yellow-orange color was detected with the main peak of SnO, and the green-blue color developed with the main peak of $Zn_2TiO_4$. The $a^*$ and $b^*$ values increased with increased SnO peak intensity, and decreased with increased $Zn_2TiO_4$ peak intensity. The results revealed that pigment color formation was influenced by changes in the main crystalline phases and crystalline intensity. However, XPS analysis of the oxidation states of each element showed little correlation with the pigment chromaticity result.

• Proceedings of the KOSOMBE Conference
• /
• v.1998 no.11
• /
• pp.309-310
• /
• 1998

Visual observation and subjective assessments lack the objective evaluation of laser therapy effects of the epidermal pigmented lesions. In this study, we proposed the two methods; One is CIE(Commission International d'Eclairage) $L^*,\;a^*,\;b^*$ coordinate system($L^*$ : brightness, $a^*$ : red(+) $\sim$green(-) content, $b^*$ : yellow(+) $\sim$blue(-) content), and the other is the relative color difference measurement. And we applied these two methods for quantitative evaluation of the laser therapy effects.

• Applied Chemistry for Engineering
• /
• v.29 no.3
• /
• pp.283-288
• /
• 2018

As the use of environmentally friendly and non-disease natural pigments grows, various methods for extracting natural pigments have been studied. The natural color was extracted from parsley, a vegetable ingredient containing natural dyes. Target color codes of green series of natural dyes extracted as variables #50932C (L = 55.0, a = -40.0, b = 46.0) were set with the pH and temperature of extracted natural color coordinates (of the extracted), and the quantitative intensities of natural dyes were analyzed. During the colorimetric analysis predicted by the reaction surface analysis method, a color coordinate analysis was conducted under the optimal conditions of pH 8.0 and extraction temperature of $60.9^{\circ}C$. Under these conditions, predicted figures of L, a, and b were 55.0, -36.3, and 36.8, respectively, while actual experimental ones confirmed were 69.0, -35.9, and 31.4, respectively. In these results, the theory accuracy and actual error rate were confirmed to be 73.0 and 13.8%, respectively. The theoretical optimization condition of the color difference (${\Delta}E$) was at the pH of 9.2 and extraction temperature of $55.2^{\circ}C$. Under these conditions the predicted ${\Delta}E$ figure was 12.4 while the experimental one was 13.0. The difference in color analysis showed 97.5% of the theoretical accuracy and 4.5% of the actual error rate. However, the combination of color coordinates did not represent a desired target color, but rather close to the targeted color by means of an arithmetic mean. Therefore, it can be said that when the reaction surface analysis method was applied to the natural dye extraction process, the use of color coordinates as a response value can be a better method for optimizing the dye extraction process.

• Archives of Plastic Surgery
• /
• v.36 no.4
• /
• pp.365-371
• /
• 2009

Purpose: Good color match holds a key position in facial reconstruction for good aesthetic result. To correct the wide facial soft tissue defect were usually used the tissue expanded cheek flap, deltopectoral flap or radial forearm free flap. This study is aimed to analyse the color difference after flap surgery by using chromameter. Method: From August 1995 to December 2006, 30 patients underwent flap operations were chosen randomly and evaluated color differences between flap site and adjacent skin. Reconstructive procedures included tissue expanded cheek flap(n = 10), deltopectoral flap(n = 10), and radial forearm free flap(n = 10). The measured sites were flap center within a radius of 1 ㎝ and four points of adjacent skin along the flap margin. The color was quantified in a three dimensional coordinate system $L^*$ (brightness), $a^*$ (redness), $b^*$ (yellowness). Results: There was no significant color difference between the pedicled flaps(tissue expanded cheek flap and deltopectoral flap) and adjacent skin area. On the other hand, color values of the radial forearm free flap were statistically different from those of adjacent skin area. Total color difference(${\Delta}E$) of tissue expanded cheek flap and deltopectoral flap were $7.45{\pm}5.78$ versus $9.41{\pm}7.09$, and that of radial forearm free flap was $11.74{\pm}3.85$. They suggest that pedicled flaps have a potential of better color match than radial forearm free flap. Conclusion: Thus, better esthetic result and satisfaction is more likely to be expected in pedicled flaps as long as it could be applied comparing radial forearm free flap.

• Archives of Plastic Surgery
• /
• v.35 no.1
• /
• pp.36-41
• /
• 2008

Purpose: For facial reconstruction, skin color match is crucial to achieve great aesthetic result. Forehead flap and full thickness skin graft have been used for many years to reconstruct facial defect. Their results are aesthetically valuable with remarkable resemblance and harmony of the skin color between donor and recipient sites. The purpose of this study is to evaluate and compare the aesthetic outcome of the two methods as the analysis of skin color match. Methods: From January 1995 to December 2005, ten forehead flaps and ten full thickness skin grafts were performed. The reconstructed areas of forehead flaps were five noses and five eyelids. Recipient sites of full thickness skin grafts were seven eyelids, two noses and one forehead. In order to obtain the objective validity, the skin color of flap(or graft) and the recipient sites were measured by chromameter. The skin colors were quantified according to a three-dimensional coordinate system used in chromameter, L*(brightness), a*(redness), and b*(yellowness).Results: There was no significant color difference between forehead flap site and adjacent skin in all color values. On the other hand, the L* and b* values of graft sites were significantly lower than those of the adjacent skins. The a* values of graft sites were higher than those of the adjacent skins. Conclusion: This study reveals that skin color match of forehead flap is greater than that of full thickness skin graft. As forehead flap has adequate volume and great color match, it can be useful to reconstruct deep facial defect such as nasal defect. On the other hand, full thickness skin graft can be used for superficial defect like partial eyelid defect.

• Applied Chemistry for Engineering
• /
• v.27 no.3
• /
• pp.325-329
• /
• 2016

Extracting natural dyes have been widely studied since the needs of eco-friendly and non-toxic natural dyes increased. In this paper, the natural dyes were extracted from sappan wood, gardenia, and mugwort containing brazilein, crocin, and chlorophyll process. After the extraction with variables of pH of solvent and reaction time, the chromaticity of extracted natural dyes was analyzed using quantitative values from brightness and color coordinate (L, a, b) based on the target colors of red, yellow and green. For the case of brazilein and crocin, the cadmium red and cadmium yellow, respectively were extracted. In the case of sappan wood and gardenia, the red pigment under pH 12 (${\Delta}$ = 18.2) and the yellow pigment at pH 9 (${\Delta}$ = 18.4) were extracted respectively. However, the color of extracted chlorophyll from mugwort was different from the target chrome green.

• Applied Chemistry for Engineering
• /
• v.28 no.3
• /
• pp.345-350
• /
• 2017

The sintered density of uranium oxide pellets for pressurized water reactors is generally analyzed with pellet's samples completed with the sintering process. In this paper, the sintered density was analyzed by the newly developed method measuring the chromatography of ammonium diuranate, a precursor of uranium oxide, by a spectrophotometer (CM-5, Konica Minolta) before completing the sintering process. As a result of the sintered density analysis based on the brightness, color coordinate values (L, a, b) obtained from five ammonium diuranate samples by a spectrophotometer and the trend line of sintered density analyzed by a previous method, the sintered density with respect to the L value was observed with 0.9967 of the decision factor $R^2$. In case of a value, $R^2$ value was 0.9534 indicating lower reliability than that of the L value. However, b value with $R^2$ value of 0.4349 showed a very low correlation.

• Journal of dental hygiene science
• /
• v.15 no.5
• /
• pp.577-584
• /
• 2015

The purpose of this study was to evaluate the effect of metal chloride infiltration treatment on color and strength changes of the yttria-stabilized tetragonal zirconia polycrystals (Y-TZP). Fifty disc specimens were prepared with a Y-TZP powder (ZPEX; Tosoh, Japan). Thirty different metal chloride solutions containing 0.03~0.08 wt% chromium and 0.03~0.07 wt% terbium ions were prepared. Presintered Y-TZP specimens were soaked in metal chloride coloring liquids for 3 minutes and sintered in air at $1,450^{\circ}C$ for 2 hours. The color of the specimens was measured with spectrophotometer and color difference (${\Delta}E^*$) was obtained based on the CIE $L^*$, $a^*$, $b^*$ color coordinate values. To evaluate the effect of metal chloride infiltration strength changes, the biaxial flexural test was performed at crosshead speed 0.5 mm/min. Colors of the sintered Y-TZP showed the colors of Vita shade guide A1, A2 and A3 with the infiltration of chromium and terbium chloride solutions. Density of the sintered Y-TZP increased by the infiltration of chromium and terbium chloride solutions. Bi-axial flexural strength of the sintered Y-TZP did not show statistically significant differences by the infiltration of chromium and terbium chloride solutions (p>0.05). Chromium and terbium chloride did not affect the crystal phase of zirconia, and all specimens showed tetragonal phase. Accordingly, this study suggests that chromium and terbium chlorides can make colored zirconia while adding in a liquid form. The color of colored zirconia differ from that of vita shade guide but it can use all ceramic restoration as substructure in dental clinic.

• Journal of the East Asian Society of Dietary Life
• /
• v.17 no.6
• /
• pp.894-902
• /
• 2007

This study was performed to observe the quality characteristics of Eunhakong dasik and Small Black Soybean dasik prepared with different addition rates of chlorella powder. For the Hunter's color values, the $L^*,\;a^*,\;and\;b^*$ values of both dasiks decreased with the addition of chlorella powder. The cohesiveness and gumminess of both dasiks were not dependant on the chlorella powder additions. However, the hardness of the Eunhakong dasik with 8% chlorella powder increased. The springiness and brittleness of the Eunhakong dasik had a tendency to decrease as the addition rate of the chlorella powder increased. In terms of sensory quality, both the dasiks were improved by the addition of 4% chlorella powder. Therefore, in subsequent examinations, the chemical characteristics of both dasiks were determined for the 4% addition of chlorella powder. The moisture and crude lipid contents of both dasiks were not influenced by the addition of chlorella powder. Carbohydrate content was highest in the Eunhakong dasik with 0% chlorella powder, and in the Small Black Soybean dasik with 4% chlorella powder. Conversely, crude protein content was highest in the Eunhakong dasik with 4% chlorella powder, and in the Small Black Soybean dasik with 0% chlorella powder. The crude lipid content of the Small Black Soybean dasik with 4% chlorella powder was lower than that of the control without chlorella powder. For mineral content, the K content of both dasiks was not influenced by the addition of chlorella powder. The Ca, Mg, and P contents of both dasiks with 4% chlorella powder, respectively, were lower than those of the dasik with 0% chlorella powder. Finally, the total amino acid content of the Eunhakong dasik tended to decrease, while that of the Small Black Soybean dasik incrased, with the 4% addition of chlorella powder.