The Art and Science of Shade Matching in Esthetic Implant Dentistry
magenta, and yellow are referred to as the subtractive primary colors: Color is created by subtracting (absorbing) certain numbers of RGB wavelengths. Conversely, the presence of all three colors (CMY) should result in all wavelengths being absorbed and none reflected/ transmitted (i.e., the color black). Although this is true for CMY dyes used in photography, use of all three colors of printing ink actually results in a muddy brown because of inherent imperfections in the ink. Therefore, black (indicated by K in order to differentiate it from blue [B]) ink is usually added to improve the appearance of darker colors and to create better shadow density, which is why “CMYK” and “four-color processing” are the terms usually associated with full-color printing (Miller and Zaucha 1992).
Pigment Colors Pigment colors contribute to the hues of an object. Because these colors are perceived through either transmission or reflection of light, they are essentially the same as the subtractive colors used in color reproduction for reflective and transmissive media, as discussed above. It is imperative to understand pigment colors in dentistry, especially because they are inherent in restorative materials such as ceramics, composites, and acrylic resins. Moreover, understanding primary, secondary, and complementary colors is critical to achieving accurate, esthetic shades.
The Primary Colors: Red, Yellow, Blue The primary pigment colors are the same as the subtractive primaries, but they are referred to as red, yellow, and blue (instead of magenta, yellow, and cyan, respectively). Like the subtractive primaries, these are the
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colors that are perceived when one of the RGB wavelengths is absorbed. Red is perceived when green is absorbed; yellow is perceived when blue is absorbed; and blue is perceived when red is absorbed.
Secondary Colors: Orange, Green, Violet The secondary colors are formed by combining two of the primary colors. For example, red and yellow create orange; yellow and blue create green; and blue and red create violet.
Complementary Colors Complementary colors are so named because they “go well” together; these are the colors often seen paired in advertising. Complementary colors are those that, when combined in equal proportions, form a dull gray that absorbs and reflects/transmits all wavelengths in equal amounts, as shown in Figure 11.5. For example, orange and blue are complementary colors because orange is a combination of red and yellow, which absorb green and blue, respectively, while blue absorbs red. Other pairs of complementary colors include red/green and yellow/ violet.
Dimensions of Color Like the teeth and restorations we try to match, color is truly multidimensional. At the beginning of the twentieth century, Professor Albert H. Munsell (1969) noted that each color has a logical relationship to all other colors. He brought clarity to color communication by establishing an orderly system for accurately identifying every color. This “color wheel” includes the dimensions of hue, value, and chroma, as shown in Figure 11.6. To
Figure 11.5. The primary pigment colors are referred to as red, yellow, and blue. The secondary pigment colors—orange, green, and violet—are formed when two primary colors are added together. When complementary colors are added together, they neutralize each other and form gray. This is clinically significant because complementary colors can be combined to lower the value of excessively bright restorations. Reproduced by permission of Quintessence Publishing, copyright Quintessence.