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Markus Otto, Winzenrender, www.winzenrender.com
The reflectance of a material refers to how it reflects the light it receives at the surface, in plain words: its surface color and intensity. They are defined by the Reflectance 0º (the color at front angles) and Reflectance 90º (color at glancing angles).
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How much influence the Reflectance 0° color vs. the Reflectance 90° color has on the look of the material depends mostly on the roughness settings and to a certain degree on the Nd. In the example below Reflectance 0 was set to red and Reflectance 90 to blue. Only the roughness was decreased from 100 on the far left to 0 on the far right.
Reflectance 0 RED, Reflectance 90 BLUE. Decreasing roughness 100, 90, 70, 50, 25, 10, 0
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It might be easier to keep Reflectance 0 colors within reasonable brightness limits by switching the Color Picker from RGB mode to HSV mode. In this mode, you control the brightness of the hue directly with the V or Value slider. This allows you to control the overall brightness with one slider instead instead of 3 for RGB, while maintaining the same hue and saturation.
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