@article{2990267,
    title = "Perceptibility and acceptability thresholds of simulated facial skin color differences",
    author = "Lagouvardos, P. and Spyropoulou, N. and Polyzois, G.",
    journal = "Journal of Prosthodontic Research",
    year = "2018",
    volume = "62",
    number = "4",
    pages = "503-508",
    publisher = "Elsevier Ireland Ltd",
    issn = "1883-1958, 2212-4632",
    doi = "10.1016/j.jpor.2018.07.005",
    keywords = "adult;  color;  color vision;  color vision test;  differential threshold;  face;  female;  functions of the skin and its appendages;  human;  male;  maxillofacial prosthesis;  physiology;  procedures;  prosthesis design;  skin, Adult;  Color;  Color Perception;  Color Perception Tests;  Differential Threshold;  Face;  Female;  Humans;  Male;  Maxillofacial Prosthesis;  Prosthesis Design;  Skin;  Skin Physiological Phenomena",
    abstract = "Purpose: This study investigates the perceptibility and acceptability thresholds (PT, AT) of observers for L*, a* and b* facial skin differences, very important for the fabrication of a maxillofacial prosthesis. Methods: One image (10 × 13.3 cm/300 dpi), simulating standard facial skin color, and 27 smaller images (4.9 × 6.0 cm/300 dpi), simulating shades with different RGB values from the standard were made, using Adobe-Photoshop CS3. The RGB values, were based on 9 stepped increases in L*, a* and b*. Images were shown in the middle of a computer screen with the standard image in the background. 90 persons with normal color vision and optical acuity were selected and instructed to evaluate 81 (27 × 3) randomly shown images for a perceptible or an acceptable (48 h later) mismatch, between central and background image. Using best fitting regression curves 50 % PT and 50 % AT for all parameters were estimated along with their 95 %CI. Results: Observers’ reliability found high (0.807–0.945) while the cubic and exponential were the best fitted curves to the data. Overall 50 % ATs were smaller than 50 % PTs (p < 0.01) and overall ΔL* parameter showed the lowest thresholds (0.119PT/0.864AT), significantly smaller (p < 0.05) than Δa* (0.993PT/2.037AT), Δb* (1.147PT/2.517AT), and ΔEab*(1.497PT/1.808AT). No differences were found between sex or age groups in 50 % ATs for Δa* and Δb* parameters, but 50 % PT for Δa* was smaller in females and in older people with the opposite for Δb*. Conclusions: Changes in L* were more perceptible and less acceptable than changes in a* and b*. For this reason ΔL* parameter needs attention equally to ΔE*ab when fabricating a facial prosthesis. © 2018 Japan Prosthodontic Society"
}