scholarly journals A New, Small-color-difference Equation for Dental Shades

1990 ◽  
Vol 69 (11) ◽  
pp. 1762-1764 ◽  
Author(s):  
W.J. O'Brien ◽  
C.L. Groh ◽  
K.M. Boenke
Keyword(s):  
Difference Equation ◽  
Color Difference ◽  
Data Set ◽  
B Values ◽  
Color Differences ◽  
Beckman Spectrophotometer ◽  
Shade Guide

Traditionally, dental-shade-guide standards are designated in terms of Munsell hue (H), value (V), and chroma (C). However, ΔE color differences proposed as ADA tolerances for shade guides are in the CIE L*a*b* system. The purpose of this study was to evaluate a new color-difference equation, for estimation of small color differences by Munsell parameters. The published values of the Bioform shade-guide tooth colors determined with a Beckman spectrophotometer were used. Color differences among 276 combinations of the 24 Bioform shade-guide colors were calculated with Eq. 1, with use of the Munsell notation, and also with the CIE L*a*b* equation for ΔE. An estimate of the accuracy of Eq. 1 was 0.41 ΔE units when ΔE CIE was below 4.0. The Vita shade-guide colors were determined with a Beckman spectrophotometer. This data set contained 16 samples, and 120 combinations were used for calculation of color difference. An estimate of the accuracy for this set of data was 0.35 ΔE units when ΔE CIE was less than 4.0. The new color-difference equation provides a means for estimation of AE CIE L*a*b* color difference between dental shades with Munsell notation. This equation will be useful for estimation of small AE CIE L*a*b* values for shade-guide teeth that are designated in terms of Munsell notation.

scholarly journals Variations in the Shades of Contemporary Dental Ceramics: An In Vitro Analysis

Crystals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1288
Author(s):  
Syed Rashid Habib ◽  
Abdulaziz Saud Al Rashoud ◽  
Turki Ali Safhi ◽  
Abdulrahman Hamad Almajed ◽  
Hamad Ali Alnafisah ◽  
...  
Keyword(s):  
Statistical Tests ◽  
Color Difference ◽  
Ceramic Materials ◽  
Dental Ceramics ◽  
Color Differences ◽  
Monolithic Zirconia ◽  
Vitro Analysis ◽  
Post Hoc ◽  
Shade Guide

Background: To identify and compare the shade variations of various commonly used esthetic dental ceramics by calculating their total-color-difference (ΔE) and translucency parameter (TP) using a spectrophotometer. Methods: In total, 165 disc specimens from three shades (A1, B1, and C1) of five ceramic materials (N = 55/shade; n = 11/ceramic material group) were prepared (Metal-ceramic (MC), IPS e.max press (Emax-P), IPS e.max layer (Emax-L), Layered Zirconia (Zr-L) and Monolithic zirconia (Zr-M)). With a spectrophotometer, the L*a*b* values were obtained. Total color differences (ΔE = [(ΔL*)2 + (Δa*)2 + (Δb*)2]1/2) and translucency parameter (TP = [(L*B − L*W)2 + (a*B − a*W)2 + (b*B – b*W)2]1/2) were calculated. The statistical tests included ANOVA and Post hoc Tukey’s analysis (p < 0.05). Results: Significant differences (p = 0.000) were found between the groups for ΔE. Highest ΔE (A1) were found for Zr-L (80.18 ± 20) and lowest for Zr-M (62.97 ± 1.28). For B1, highest ΔE values were noted for MC (76.85 + 0.78) and lowest for the Emax-L (62.13 ± 1.49). For C1, highest ΔE values were found for the MC group (73.96 ± 0 67) and lowest for Emax-P (55.09 ± 1.76). Translucency variations between tested ceramics were revealed (p < 0.05). Highest TP values (A1) were found for Emax-L (2.99 ± 1.64) and lowest for Zr-L (0.35 ± 0.16). For B1, highest TP values were noted for Emax-P (3.50 ± 1.74) and lowest for MC (0.57 ± 0.40). For C1, highest TP values were found for Emax-P (4.46 ± 2.42) and lowest for MC (0.58 ± 0 48). Conclusions: Significant differences in ΔE and TP were found for tested ceramic groups. The color differences of the tested materials varied according to clinical acceptability, even with the selection of same color/shade. The color/shades of the various dental ceramics do not match with the vita shade guide tabs, to which they are compared most often. Shade differences are present between different lots of ceramic materials from the same or different brands.

Evaluation of CIELAB-Based Color Difference Formulae Using a Printing Data Set

2010 ◽  
Vol 174 ◽  
pp. 44-47
Author(s):  
Yuan Lin Zheng ◽  
Shi Sheng Zhou ◽  
Lin Lin Zhang ◽  
Yong Hong Qi
Keyword(s):  
Statistical Significance ◽  
Color Difference ◽  
National Standards ◽  
Data Sets ◽  
Printing Industry ◽  
Data Set ◽  
Visual Color ◽  
Difference Formula ◽  
Color Differences ◽  
The Difference

Color difference used to test the quality of printing products is one of the most important factors in the printing industry. Many new color difference formulae such as CIEDE2000, CIEDE94, CMC(l:c) etc were developed to improve the uniformity. In this paper the color difference formulae have been compared throughout their weighting functions SL, SC, and SH to the CIELAB components , , . In order to test which color difference formula has the better performance in the printing industry they are evaluated by our own data sets. First of all, we developed a printing data set for evaluating color difference with psychophysical methods. And the visual color differences of every pairs were obtained. After that the color difference formula mentioned before were evaluated using the data set with the standardized residual sum of squares (STRESS) methods which has better mathematical properties to evaluate the performance of color difference formulae using ΔV and ΔE than PF/3 that cannot indicate the statistical significance of the difference between two color-difference formulae. The result shows that CIEDE2000 and CIE94 color difference formulae are better than CIELAB and CMC. Finally we recommend that the national standards and occupation standards should be updated and CIEDE2000 should be popularized in the printing industry.

scholarly journals A MONITORING METHOD OF COLOR DECAYING FOR COLORED PATTERNS IN ARCHITECTURAL HERITAGE

2019 ◽  
Vol XLII-2/W11 ◽  
pp. 1193-1198
Author(s):  
L. Zhang ◽  
J. Xie ◽  
L. Qin ◽  
Z. Liu ◽  
G. Liu
Keyword(s):  
Good Health ◽  
Color Difference ◽  
Health Condition ◽  
Architectural Heritage ◽  
Monitoring Method ◽  
Special Part ◽  
Color Differences ◽  
The Status ◽  
Set Up ◽  
Colored Pattern

<p><strong>Abstract.</strong> As a special part of architectural heritage, the colored pattern is not only artwork to decorate the architecture, but information reflecting specific historical era. So it has great cultural and artistic value. However, the colored pattern is one of the most sensitive types of cultural relics, which is sensitive to natural environment changes and highly vulnerable to erosion. In order to strengthen the protection of colored patterns in history architectures, it is necessary to monitor the status quo of them.</p><p>This work introduces a monitoring method of color decaying for colored patterns in architecture: set up the illuminants, adjust the illuminants, detect the color information and calculate the color difference. Based on the color difference by CIE DE2000 formula, the color decaying status of the pattern can be evaluated. The monitoring period should be at least three months.</p><p>About four years’ work has been carried out for colored patterns in the Long Corridor of the Summer Palace, and the color differences &amp;Delta;E<sub>00</sub> are about from 2 to 5, some can be over 9. In result, most colored patterns keep in good health condition. Color decaying happens every time and there are slight changes in most colored patterns. In 2nd quarter 2017, aware changes happened in nearly all the patterns. According to the color difference to evaluate the color decaying of the colored patterns, it is an efficient method to analyze the health status of colored patterns.</p>

scholarly journals Color Alteration of Encapsulated Beetroot (Beta vulgaris L.) Extract Upon Dissolving in Various pH Treatment

2020 ◽  
Vol 2 (02) ◽  
pp. 48
Author(s):  
Diah Mustika Lukitasari ◽  
Renny Indrawati ◽  
Rosita Dwi Chandra ◽  
Heriyanto Heriyanto ◽  
Leenawaty Limantara
Keyword(s):  
Beta Vulgaris ◽  
Structural Changes ◽  
Color Difference ◽  
Prolonged Storage ◽  
B Values ◽  
Ph Adjustment ◽  
Natural Pigments ◽  
Hue Angle ◽  
Color Alteration ◽  
Ph Range

It has been known that most natural pigments are unstable upon exposure against several environmental factors, such as thermal treatment, light, oxidizing or reducing agents, as well as acid or alkaline compounds. Encapsulation procedures is often adopted to adjust the solubility and provide protection to the natural pigments. Here, we prepared an encapsulated beetroot extract as the candidate of red bio-colorant. The primary aim of the present study is to investigate color alteration of encapsulated beetroot (Beta vulgaris L.) extract upon dissolving in various pH adjustment and prolonged storage. The McIllvainne buffer was prepared in various pH range, i.e. from 2 to 11. The encapsulated extract (0.1% w/v) was dissolved and the color of the solutions were measured regularly until 3 days storage under darkness at 200C. Any degradation or structural changes will cause color alteration, which were monitored through L*, a*, b* values, the hue angle (H°), chroma values (C), as well as color difference (DE). The results showed that pH 4 was the most favorable condition that brings least impact to the color alteration, even when the colored solution was kept in prolonged storage until 9 days.

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