Perceived color shift of a shade guide according to the change of illuminant.
BACKGROUND
The perceived color of shade guide tabs is influenced by different spectral compositions of different light sources, and this can influence color matching.


OBJECTIVE
The purpose of this study was to determine the amount of perceived shift in color and color coordinates of a shade guide using 3 different light sources: CIE standard illuminant D65 (daylight), A (incandescent lamp), and F9 (fluorescent lamp).


METHODS
CIE color coordinates L*, a*, b*, chroma, and the spectral reflectance of shade tabs in a shade guide (Vitapan 3D-Master) were measured by a spectroradiometer under D65, A, and F9 simulators. Perceived color and color coordinate shifts due to the change of illuminant were determined. The influence of the type of light and shade designation of the 26 tabs on the color coordinates was analyzed by a 2-way ANOVA; correlations in the color coordinates between each corresponding pair under the 3 illuminants were determined (α=.05).


RESULTS
All of the color coordinates were influenced by the type of illuminant and shade designation of the shade tabs (P<.001); however, each corresponding coordinate pair showed significant correlations under different illuminants (r=0.930 to 0.997, P<.01). Color differences under different illuminants were in the range of 3.1 to 9.1 ΔE units; all of these differences were perceptible (ΔE>2.6). Lightness decreased and chroma increased when the illuminant was changed from the D65 simulator to the A or F9 simulators.


CONCLUSIONS
Perceptible shifts in the color of shade guide tabs under different ambient lighting conditions were confirmed by a spectroradiometer; these color shifts were influenced by the type of illuminant used.
Senior Scientist, Institute for Clinical Performance of Biomaterials, Seoul, Korea. ykleedm@gmail.com
Yong-Keun
YK
Lee
Bin
B
Yu
Jin Ik
JI
Lim
Ho-Nam
HN
Lim
D000704:Analysis of Variance; D003116:Color / Q000592:standards*; D003118:Color Perception; D003124:Colorimetry / Q000295:instrumentation / Q000379:methods*; D017267:Dental Prosthesis Design; D008029:Lighting; D013053:Spectrophotometry