The Gaussian texture is based on a Gaussian distribution spectrum. Wavelength sets the center of the spectrum, and Width sets the width of the curve (Figure 1). The narrower the width, the more pure and saturated the color.
Figure 1: The Color Gaussian parameters
Wavelength - This represents the mean wavelength approximation between 380 - 720 nm. The lower wavelength values appear bluish, while higher wavelengths (around 700 nm) appear reddish.
Width - Almost no color is visible when using a Width of 0.000. On the other hand, a Width of 1.000 means the color is spread thin over a large space, and the texture appears faint.
Power/Brightness - The brightness of the texture.